chapter 31 trachea: anatomy and pathology · visibility of the bony thorax and improves imaging of...

31Trachea: Anatomy and Pathology

J. Pierre Sasson, Nadir G. Abdelrahman,Suzanne Aquino, and Michael H. Lev

INTRODUCTIONANATOMY AND PHYSIOLOGY

Gross Anatomy/HistologyInnervation and Blood SupplyLymphatic DrainageSurrounding Anatomic Structures

RADIOGRAPHIC EVALUATION OF THETRACHEAPlain RadiographsCT ScanningMR ImagingVirtual Bronchoscopy

PATHOLOGIC CONDITIONSCongenital Abnormalities

TracheomalaciaCongenital Stenosis (Subglottic/Tracheal)Tracheal BronchusTracheal Diverticula (Tracheocele)Tracheoesophageal FistulaVascular Rings and Slings

Diffuse Disorders of the Trachea(Nonneoplastic)Conditions Causing Narrowing of the

TracheaInfectionTuberculosisHistoplasmosisRelapsing Polychondritis

Granulomatous Disease of the TracheaSarcoidosisAmyloidosisTracheopathia OsteochondroplasticaSaber-Sheath Trachea

Diffuse Conditions Causing Widening of theTracheaTracheobronchomegaly (Mounier-KuhnSyndrome)

Secondary TracheomegalyTrauma

Posttracheostomy/PostintubationComplications

Tracheal TumorsGeneral ConsiderationsMalignant TumorsSquamous Cell CarcinomaAdenoid Cystic CarcinomaMucoepidermoid CarcinomaChondrosarcoma

Benign TumorsBenign Vascular TumorSquamous Cell PapillomaCartilaginous Tumors and HamartomasCarcinoid TumorBenign Mixed Cell Tumors

Tumor-Like Conditions

INTRODUCTION

The trachea is a flexible cylindrical tube composed ofcartilaginous rings, connected by a fibromuscular membraneand lined internally by mucosa. The trachea facilitates thepassage of air between the larynx and the lungs. It ispositioned midline in the neck and courses slightly to theright in the upper thorax. It extends from the cricoid

cartilage superiorly (at about the level of the sixth cervicalvertebra) to the carina inferiorly.1 The location of the lowerend of the trachea varies with body posture, and withinspiration and expiration, and in deep inspiration the carinamay descend to the level of the sixth thoracic vertebra.2

The length of the trachea ranges from 10 to 13 cm, averagingapproximately 11 cm.2 Viewed laterally, the trachea as-sumes an oblique course, running from superoanterior to in-

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feroposterior. In severely kyphotic patients, the trachea mayhave a horizontal orientation.

The degree to which the laryngeal glottis (true vocalfolds) is open significantly affects airflow patterns in thetrachea. The glottis has the smallest, yet the most variable,cross-sectional area of the upper respiratory tract. Aircurrents in the upper trachea are typically turbulent duringinspiration, with a transition to more laminar flow in themiddle and distal trachea. The velocity of the air streamin the distal trachea during quiet respiration is approximately1 mm/sec.2 During forced expiration or coughing, intra-thoracic pressure becomes positive, transmural pressuredifferences increase, and narrowing of the intrathoracictrachea occurs. This narrowing accelerates airflow andfacilitates expectoration. The airflow in the central tracheaduring coughing has been estimated to be approximately250 km/hr.3 Airflow patterns in the trachea are significantlymore complicated in cases with tracheal stenosis or tracheo-malacia.

Gross Anatomy/Histology

The skeleton of the trachea is composed of 16 to 20incomplete hyaline cartilaginous rings that are bound in atight elastic connective tissue oriented longitudinally.1

These cartilage rings may calcify with age and two or morecartilages may unite, either partially or fully. Rarely, theymay bifurcate posteriorly. The cartilage forms about twothirds of the circumference of the trachea. Because theposterior border of the trachea is formed by fibromuscularmembrane, the cross-sectional shape of the trachea is that ofthe letter D, with the flat side posterior. The first and lastcartilaginous rings differ from the rest of the tracheal rings.The first ring, located approximately 1.5 to 2 cm below thetrue vocal cords, is partly recessed into the broader ring ofthe cricoid cartilage and is the broadest of all the cartilagerings. The first ring is sometimes merged to the cricoidcartilage or to the second tracheal ring. The second, third,and fourth rings are surrounded anteriorly and laterally bythe thyroid gland.2 The last tracheal ring is thicker andbroad, and on its lower border there is a triangular processthat curves downward and backward between the origins ofthe bronchi.4 The mucosal portions of the posterior tracheaare separated from the esophagus by a thin layer ofconnective tissue. This region is often referred to as thecommon party wall, as it separates the trachea in front fromthe esophagus behind.

The cartilaginous rings allow the tracheal lumen to retainits patency, even in the extreme circumstances of coughingand forced expiration. The diameter of the tracheal lumen,like its length, depends on the height, age, and gender ofthe individual. In men, tracheal diameter ranges from 13 to25 mm in the coronal plane and 13 to 27 mm in the sagittalplane. Tracheal diameter is slightly less in women, rangingfrom 10 to 21 mm in the coronal plane and 10 to 23 mm inthe sagittal plane.1 Cross-sectional area correlates mostclosely with height in children. With increasing age, thetransverse section of the tracheal lumen successivelyassumes the following shapes: round, lunate, flattened, androughly elliptical. Respiratory cycle, certain maneuvers, andbody position also contribute significantly to the variation in

lumen shape. During rapid deep inspiration, the thoracicportion of the trachea widens and the cervical portionnarrows. The opposite pattern occurs during expiration; theextrathoracic tracheal lumen increases in size duringcoughing, Valsalva maneuver, or forced expirations,whereas the intrathoracic portion decreases.2

The trachea is lined by pseudostratified columnarepithelium that sits on an elastic lamina propria. Gobletmucous cells and small subepithelial glands that secrete ontothe luminal surface are interspersed among the ciliatedcolumnar cells.3 There has been recent interest in studyingthe small intercellular bridges (tight junctions) situatedbetween the ciliated cells.5 These junctions may explain theobservation that cilia in the respiratory tract move in asynchronous and coordinated manner. The cilia beat about1000 times per minute, propelling the mucous lining upwardtoward the pharynx, from which it can be coughed upseveral times a day. Normally, the amount of broncho-tracheal secretions expelled is quite small, averaging 10 ccover a 24 hour period.3 Mechanical irritation by endotra-cheal tubes or suction devices, however, can increase thisvolume 10-fold. During disease states, the amount andquality of the periciliary fluid and mucous can change,interfering with the drainage and protective functions of themucosa.

Each tracheal cartilage has a perichondrium, continuouswith a dense fibrous membrane that is between adjacentcartilages and within the posterior membranous wall. Theperichondrium and membrane are composed primarily ofcollagen with some elastin fibers. Smooth muscle fibers(trachealis muscle) are in the membrane posteriorly. Most ofthese muscle fibers are transverse, attaching to the free endsof the tracheal cartilages and providing alteration in thetracheal cross-sectional area. There are also longitudinalfibers. The trachealis muscle can diminish the caliber of thetracheal lumen or prevent overdistention of the trachea whenthere is abdominal straining prior to coughing.

Innervation and Blood Supply

The trachea is innervated by parasympathetic trachealbranches of the vagus nerve, by the recurrent laryngealnerve, and by sympathetic nerves. The parasympatheticpreganglionic nerve fibers send their axons to local gangliain the tracheal wall. The sympathetic postganglionic supplycomes from both the cervical ganglia and the second throughfourth thoracic ganglia. The parasympathetic postganglionicas well as the sympathetic fibers innervate seromucousglands, smooth muscles, and blood vessels.6 Trachealsmooth muscle, controlled by these autonomic nerves,contracts to narrow and stabilize the tracheal lumen,preventing excessive invagination of the dorsal membrane.

Branches of the recurrent laryngeal nerve perforate thelateral tracheal wall, providing a rich supply of sensoryafferents to the inner tracheal mucosa. The trachea has asegmental blood supply, shared largely with the esophagusand derived from multiple branches of the inferior thyroidaland bronchial arteries. The inferior thyroidal arteries, as wellas the extreme right intercostal artery, supply the superiorportion of the trachea; branches from both the bronchialarteries and the third intercostal artery supply the inferior

Chapter 31 Trachea: Anatomy and Pathology 1701


portion of the trachea. Tracheal venous drainage is to theinferior thyroid venous plexus.

Lymphatic Drainage

Numerous lymph nodes surround the trachea, mostnotably in the carinal region. The major lymph node groupsare the inferior tracheobronchial nodes and the right and leftsuperior bronchial nodes. The lymphatic drainage from theproximal two thirds of the trachea passes through to thepre- and paratracheal lymph nodes (level VI), eventuallydraining into the lower jugular nodes (level IV).

The pattern of tracheal lymph node drainage is importantfor the radiologist to be aware of for the purpose of lungcancer staging. For example, left apical lung cancers tendto drain to aortopulmonary window nodes rather than tohilar and paratracheal nodes. Lower-lobe cancers are morelikely to drain to hilar nodes, followed in frequency bysubcarinal and paratracheal region nodes. Staging of lungcancer, according to the American Thoracic Association, isbased largely on knowledge of the nodal stations of themediastinum—particularly the paratracheal nodes.7

Surrounding Anatomic Structures

The trachea is surrounded by the esophagus, thyroidgland, lungs, aorta, vagus nerves, recurrent laryngeal nerves,and azygos veins. It moves vertically with neck extension orflexion relative to these structures. The esophagus is posi-tioned directly posterior to the cervical portion of the tracheaand typically extends slightly to the left of the intrathoracicportion. Foreign bodies or tumors of the esophagus maytherefore manifest with airway symptoms due to compres-sion of the posterior membranous trachea (common partywall). On plain film radiography, the thin tracheal wall (1 to2 mm) is well defined by air in the tracheal lumen, as well asby the adjacent mediastinal fat. As mentioned, cartilaginouscalcification is increasingly common with age, especially inwomen.1

The vagus nerve exits the skull base at the jugularforamen and courses inferiorly along the posterolateralaspect of the carotid artery. On the left, the recurrentlaryngeal nerve loops from anterior to posterior under theaortic arch, at the ductus arteriosus, where it begins itsascent. On the right, it similarly loops under the subclavianartery. The recurrent laryngeal nerves ascend bilaterally inthe tracheoesophageal groove.8 The course of the leftrecurrent laryngeal nerve is of clinical interest for severalreasons. An aneurysm of the aorta, or another mass lesion,can apply traction to the nerve, resulting in recurrentlaryngeal nerve palsy. A very rare mechanism of recurrentlaryngeal nerve palsy relates to severe coughing spasms,during which the heart and great vessels can create tractionon the left recurrent laryngeal nerve sufficient to causeneuropraxia.

Under normal conditions, the aortic arch courses anteriorto the intrathoracic trachea, along the left and dorsally. Themost fixed point of the trachea is in this region. Thedescending aorta may cause a slight impression at the lowerleft trachea. The innominate (brachiocephalic) artery crosses

anterior to the trachea and can cause an indentation,particularly in infants. The azygos vein crosses the distaldorsal trachea toward the right tracheobronchial angle, andrarely produces an indentation. In infancy, the innominatevein lies anterior to the lower cervical trachea; in adulthood,this vein is intrathoracic.9, 10

RADIOGRAPHIC EVALUATION OF THETRACHEA

The radiologic evaluation of the trachea includes plainfilms (both lateral neck and anteroposterior high-kilovoltageviews), tomograms, computed tomography (CT), and mag-netic resonance (MR) imaging.11 CT is of great value in as-sessing the spectrum of disease that affects the tracheaand has largely become the imaging modality of choice, es-pecially now that two-dimensional and three-dimensionalreformatted views can be routinely obtained through imagepostprocessing. Airway fluoroscopy, barium studies of theesophagus, angiography of vascular lesions, and conven-tional tomography all may play a part in the evaluation oftracheal pathology.

Plain Radiographs

Plain chest radiography in the posteroanterior (PA) andlateral projections is the most frequently used imagingtool for patient screening (Fig. 31-1). A high-kilovoltage(140 kVp) technique is preferred because it reduces thevisibility of the bony thorax and improves imaging of thevarious mediastinal structures. There is considerable overlapof the trachea with the mediastinum and bony thorax,making many tracheal lesions difficult to visualize. Thelateral neck film, obtained with the head slightly hyperex-tended, is useful for studying the cervical trachea. Flexion ofthe neck, especially in children, may cause buckling of thetrachea, resulting in the appearance of a prevertebral‘‘pseudomass.’’ The majority of patients with trachealpathology require further imaging evaluation with CTscanning.

CT Scanning

CT has largely become the imaging modality of choicefor most tracheal lesions. It allows direct visualization of thecross-sectional tracheal airway, and can be used todetermine the size, extent, and attenuation value of a lesion.Helical (spiral) CT, with 1 to 1.5 mm thin sections, allowshigh-quality multiplanar reconstruction, facilitating detailedevaluation of disorders such as tracheal stenosis and tumors.CT is helpful in the evaluation of tracheal neoplasms thatinvade the mediastinum, as well as in the evaluation of otherlesions such as goiters or vascular rings that may compressthe trachea. CT can also be used to determine accurately thelength of a tracheal lesion relative to the endoscopicreference points of either the larynx or the carina. CT canidentify enlarged lymph nodes along the tracheal wall and inthe mediastinum. It can also identify calcific or fatty

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densities, as well as vascular enhancement of tumors oraneurysms. Abnormal collapsibility of the trachea (i.e.,tracheomalacia) can be identified by paired inspiratory/expiratory CT scans. CT is also useful in directing surgicalor fine needle aspiration (FNA) biopsy of more aggressivelesions. Finally, spiral CT angiography with 3D reconstruc-tion methods (Fig. 31-2) may reveal vascular anomaliesaffecting the tracheal lumen.

Congenital lesions affecting the trachea typically requirea chest X-ray as a screening examination, followed by MRimaging or spiral CT to identify vascular anomalies ormediastinal masses. Inspiratory and expiratory CT can beused to investigate tracheal stenosis. CT is also the imagingmodality of choice to investigate tracheal stenosis due tointubation or tracheotomy tubes. Finally, spiral CT isconsidered a valuable tool in the investigation and treatmentplanning of all lesions that will undergo endoscopictherapy.12

MR Imaging

MR imaging can be utilized in the assessment of trachealstenosis and tumors. However, the current role of MRimaging is quite limited, as its spatial resolution does notpermit adequate evaluation of the segmental bronchi and thelonger scan times allow for respiratory motion imagedegradation. MR imaging, however, can depict a moderatedegree of anatomic detail without employing ionizingradiation or iodinated intravenous contrast medium.13

T1-weighted sequences demonstrate the anatomy of thetrachea and surrounding structures in detail, whereasT2-weighted sequences add to the characterization of lesionsignal differences, such as differentiation of cystic fromsolid masses. MR imaging is particularly useful in cases oftracheal compression by vascular rings and slings or byother mediastinal masses.

Virtual Bronchoscopy

Three-dimensional reconstruction of helical CT datapermits navigation through the tracheobronchial tree viareal-time simulated bronchoscopy. Recent advances incomputer technology allow faster imaging times with adecrease in radiation dose and motion artifact. Unlikeconventional fiberoptic bronchoscopy, virtual broncoscopy(VB) permits visualization of the relationship between anairway lesion and the surrounding mediastinal structures aswell as airway patency beyond a stenosis. In addition, theviewer can repeatedly navigate through the airway withoutadverse consequences to the patient. The level of obstructionand the width and length of an airway stenosis can easily bemeasured. This information can be used in preoperativeplanning for resection of tracheal tumors or for palliativestent placement. VB also appears to be useful in imagingpediatric disorders such as vascular rings, tracheomalacia,and congenital tracheoesophageal fistula.

Despite initial enthusiasm, however, the practical appli-cation of volume rendering techniques remains in question.

FIGURE 31-1 Large cell carcinoma. Posteroanterior (A) and lateral (B) views of the chest demonstrate a large,broad-based endoluminal mass arising from the right lateral tracheal wall (arrow in A).



Conventional axial CT and virtual images are equallyaccurate in estimating the maximal luminal diameter andcross-sectional area of the central airways. Sufficient clinicaldata are not yet available to judge whether VB offers a truebenefit to patients over that of the already high predictivevalues of conventional CT. Although VB may not offerimproved diagnostic accuracy, it is a promising techniquethat tends to enhance the overall understanding of a diseaseprocess, and it will likely prove useful in surgical planningand communication of imaging results to referring clinicians(Figs. 31-2B, 31-3, and 31-4).14, 15

PATHOLOGIC CONDITIONS

Clinical detection of tracheal disease is notoriously diffi-cult. With healthy lungs, occlusion of more than 75% of thetracheal lumen is necessary to cause symptoms of airwayobstruction at rest.1 Occlusion of about 50% of the cross-sectional tracheal airway is needed to produce symptoms ofdyspnea on exertion. As a result, early identification oftracheal pathology is unusual. Symptoms such as hemopty-sis, wheezing, or coughing may not manifest until disease isadvanced. Radiographically, the trachea is often a blind spoton conventional X-rays, with lesions not identified until theyare quite large. CT is the standard method for imaging apatient who has clinical symptoms suggesting trachealobstruction.

Congenital Abnormalities

The trachea can be affected by an intrinsic anomalyisolated to the trachea or by an anomaly of the contiguoussoft tissues that causes external pressure on the airway.Some abnormalities, such as stenosis or tracheomalacia, can

occur as an isolated phenomenon or in conjunction with asecond abnormality.

TracheomalaciaTracheomalacia is defined as collapse of the trachea on

expiration, resulting in more than 10% to 20% obstruction ofthe airway. It is characterized by abnormal flaccidity of thetrachea during the respiratory cycle, leading to abnormalcollapse of the thoracic tracheal segment on expiration.Weakness of the tracheal wall results from softening of thesupporting cartilage, with abnormal widening of theposterior membranous (noncartilaginous) wall. Frequently,

FIGURE 31-3 Squamous cell carcinoma. Three-dimensional virtualbronchoscopic images demonstrate intraluminal extension of tumor abovethe carina.

FIGURE 31-2 Postpneumonectomy syndrome. A 28-year-old female with congenital hypoplasia of the rightlung who underwent right pneumonectomy following recurrent pulmonary infections. Several months after surgery,the patient developed severe shortness of breath. A, Contrast-enhanced axial CT scan of the chest shows rightmediastinal shift, with herniation of the left lung into the right hemithorax (upper row). Note the compression of theproximal left mainstem bronchus between the transverse aorta and the vertebral body (arrow, left upper row). Themediastinal shift was corrected by insertion of saline breast implants (short arrows, lower rows) into the rightpneumonectomy space. Following this, the trachea was midline and the compression of the left mainstem bronchuswas resolved. B, Three-dimensional reconstructions from the dataset in A before and after placement of salineimplants.



the anterior and posterior tracheal walls move closertogether during respiration and coughing, reducing theintraluminal diameter (Figs. 31-5 and 31-6). The unsup-ported posterior wall may balloon anteriorly into the airway.Patients complain of inspiratory and/or expiratory stridor,wheezing, barking cough, or recurrent respiratory infections.The triad of an anterior bulging posterior tracheal wall,narrowed anteroposterior tracheal luminal diameter, andwidened posterior membranous tracheal wall is typical.Tracheomalacia is the major cause of respiratory difficultyfollowing repair of a tracheoesophageal fistula.

Patients with tracheomalacia may present with minimalsymptoms or with severe, life-threatening airway obstruc-tion. In children, the tracheobronchial tree is more collaps-ible than in adults. Hence, the classic expiratory stridor oftracheomalacia may be present at birth. Tracheomalacia canbe categorized into either primary intrinsic or secondaryextrinsic forms. Primary tracheomalacia is caused by aninherent defect of the tracheal cartilaginous rings. Insecondary tracheomalacia, airway collapse on expirationmay be due to extrinsic tracheal compression by a mass orvascular structure, as well as by conditions causing intrinsicweakness of the tracheobronchial structures. Secondarytracheomalacia may be associated with conditions such astracheoesophageal fistula, laryngotracheal esophageal cleft,cardiac abnormalities, or vascular compression. Localizedtracheomalacia is associated with tracheotomy.

Airway fluoroscopy, combined with a barium swallow,can demonstrate evidence of vascular compression. Rigidbronchoscopy is helpful for evaluating the degree oftracheobronchial tree collapse, as well as for documentingthe presence of associated congenital airway anomalies.Cine CT imaging and 3D imaging of the trachea duringinspiration and expiration are newer modalities that arelikely to prove useful.16 In cases of suspected vascularcompression or cardiac anomalies contributing to tracheo-malacia, MR imaging and echocardiography can also beperformed.

Mild cases of primary tracheomalacia often do notrequire treatment, because they often resolve within the first1 to 2 years of life. In cases of severe airway obstructionwith tracheal collapse, tracheostomy with long-term positiveairway pressure ventilation may be indicated. Surgicaldecompression of the trachea may lead to significantimprovement in cases of vascular compression. Differentsurgical procedures have been developed for the treatmentof tracheomalacia, with various degrees of success. Theseprocedures include placement of internal and external stents,segmental resection, and cartilage grafting to the trachea.

Congenital Stenosis (Subglottic/Tracheal)Congenital stenosis is an uncommon abnormality that

usually is associated with other major or minor anomalies ofthe respiratory tract skeleton or other organ systems.

FIGURE 31-4 Mucoepidermoid carcinoma. A 72-year-old femalepresented with intermittent hemoptysis and shortness of breath onexertion for 8 weeks. A, Axial contrast-enhanced CT scan demonstratesa well-defined, pedunculated, partially calcified mass with minimalenhancement arising from the anterior right lateral wall of the trachea(arrow). B, Sagittal and coronal CT reconstructions demonstrate themass to be located approximately 3 mm above the carina. C, Virtualbronchoscopy shows the intraluminal extension of tumor.



Commonly, there is an association with the H-typetracheoesophageal fistula, pulmonary hypoplasia, and avascular sling. The affected segment of trachea has rigidwalls with a narrowed lumen. The stenotic segment can be

focal or affect the entire trachea, extending into themainstem bronchi. Cartilages can be complete rigid rings.

Clinically, presentation occurs within the first weeks ormonths of life. Although segmental resection has beenreported, it is rarely feasible due to the length of the stenoticsegment. Most cases are treated conservatively and thepatient may live with the stenosis, the tracheal lumengrowing larger as the patient ages. However, approximatelyone half of these patients die either of the stenosis andassociated pulmonary infections or of the major congenitalanomalies associated with it.

Tracheal BronchusThe term tracheal bronchus refers to any well-defined

airway that arises from the trachea above the level of thecarina. Although this anatomic configuration is normal formany mammals, it represents an anomaly in humans and isfound in only 0.25% to 1% of the population.17 Although theanomalous bronchus typically arises from the tracheal wallless than 2 cm above the tracheal bifurcation, it may arise ashigh as 6 cm above the carina. The tracheal bronchusoriginates more frequently from the right, rather than fromthe left, in which case it supplies a variable portion of themedial or apical right upper lobe (Fig. 31-7). The incidenceof this anomaly is greatest in patients with other coexistingcongenital malformations such as congenital tracheobron-chial stenosis, aberrant pulmonary artery, Down’s syn-

FIGURE 31-6 Tracheomalacia. A 62-year-old female with anincreasingly loud, uncontrollable cough. Inspiratory and expiratory axialCT images of the upper thorax demonstrate a 44% reduction in theanteroposterior tracheal diameter on expiration. Both flexible and rigidbronchoscopy revealed a flattened, lax trachea with a redundantmembranous wall.

FIGURE 31-5 Tracheomalacia. A, Fluoroscopic evaluation of this71- year-old man with a 5-year history of progressive stridordemonstrates diffuse narrowing of the trachea with expiration. Theluminal diameter of the trachea was reduced by approximately 50%(arrows). Nonenhanced axial CT scan, filmed in lung windows, againdemonstrates tracheal narrowing on expiration (C, arrows) comparedwith inspiration (B, arrows).



drome, right aortic arch, or lung hypoplasia.18 Althoughfrequently asymptomatic, patients with tracheal bronchusmay develop recurrent infections or bronchiectasis due tostenosis at the origin of the bronchus. Pooling of secretions,and/or obstruction of the orifice of the tracheal bronchus byan endotracheal tube, may cause atelectasis. Thus, it isimportant to keep this airway anomaly in mind when caringfor patients with unusual sensitivity to endotracheal tube(ETT) position or with chronic right upper lobe atelectasis.

Tracheal Diverticula (Tracheocele)A tracheocele is an outpouching or diverticulum of the

posterolateral wall of the trachea.19 Tracheocele is a rarecondition that results from muscular weakness of thetracheal muscle. Wide-mouthed tracheoceles are likelyacquired, whereas narrow-mouthed tracheoceles are likelycongenital in origin (Fig. 31-8). Tracheoceles may betransient, seen only during periods of increased intratrachealpressure. Occasionally, on chest radiographs, they maypresent as thin-walled paratracheal air-filled cavities, with orwithout air-fluid levels. CT best displays these lesions andcan provide 3D imaging of their size and extent, along withvolumetric reconstruction. Although tracheoceles tend to beasymptomatic, they may become quite capacious andaccumulate debris. This debris may spill into the lungs andcause pneumonia.

Tracheoesophageal FistulaTracheoesophageal fistula (TEF) is a common congenital

anomaly, with an average frequency of 1 in 3000 to 4000births, and is often associated with esophageal atresia.20

TEF can exist in a number of forms (Fig. 31-9), the mostcommon configuration being that of a proximal esophagealatresia with a distal TEF (Figs. 31-10 and 31-11). Thisanomaly may be associated with severe neonatal respiratorydistress, often necessitating immediate tracheostomy. Ap-proximately 85% of neonates with this TEF present withinthe first 24 hours of life with excessive mucus production,cough, choking, and cyanosis associated with feeding.21 Inapproximately half of the patients with TEF and esophagealatresia, more than one fistula may be present. Associated

FIGURE 31-8 Tracheal diverticulum. A, Nonenhanced CT scan ofthe upper thorax demonstrates a small tracheal diverticulum arising fromthe right posterior lateral wall of the trachea (arrow). Pleural thickeningis also noted in this patient after bilateral lung transplantation for cysticfibrosis. B, Eight-month follow-up CT demonstrates a well-formed,slightly larger tracheal diverticulum (short arrow). C, Mediastinal andlung windows from a contrast-enhanced CT scan through the lung apicesin a different patient also demonstrate a diverticulum projecting off theright posterior lateral tracheal wall (arrow).

FIGURE 31-7 Right tracheal bronchus. Contiguous axial CT imagesthrough the upper thorax demonstrate an anomalous right upper lobebronchus (arrow) arising directly from the trachea in this patient withmetastatic bladder carcinoma.



anomalies involving the cardiovascular, gastrointestinal,renal, or central nervous system may also be present.22

Patients with normal birth weight and no other congenitalmalformations have the highest rates of survival. The overallsurvival rate is approximately 80%.2

H-type TEF, without esophageal atresia, is a lesscommon type of TEF that has more subtle clinicalmanifestations and is characteristically associated withgastroesophageal reflux. Symptoms may include excessiveoral secretions, respiratory distress, or immediate regurgita-tion of feedings; intermittent dysphagia and choking mayalso be present. The diagnosis of this type of TEF may bedelayed until adulthood. Patients with H-type TEF usuallyhave no associated congenital anomalies or can havecongenital tracheal stenosis.

TEF with esophageal atresia is easily diagnosed by thefailure to pass a radiopaque nasogastric tube into thestomach. The tube coils in the proximal esophageal pouchand can be seen on routine chest radiography or after theinstillation of a small amount of water-soluble contrastmaterial (Fig. 31-10B). Associated aspiration pneumoniamay be present. Tracheomalacia may develop at the fistula

site, usually resolves by the age of 2 years, and is bestdiagnosed by collapse of the airway structures on directfluoroscopy. Patients with esophageal atresia and bothproximal and distal TEFs (rare) may have gaseous disten-tion of the gastrointestinal tract with aspiration pneumonia.This diagnosis can be confirmed by contrast studies. Bariumswallow with fluoroscopy is typically employed to diagnoseH-type fistulas. Cine-esophagography (cinefluorography orfluoroscopy with videotaping) can assist in differentiat-ing TEF from simple laryngeal aspiration. Combinedbronchoscopy and esophagoscopy have also been useful inincreasing the ability to diagnose TEF. Surgery is thetreatment of choice.23

Vascular Rings and SlingsVascular anomalies of the great vessels include ‘‘rings’’

and ‘‘slings’’11, 24, 25 (see also Chapter 29). Airway com-pression by vascular anomalies may be congenital oracquired. In children, vascular impressions on the tracheaare generally congenital and may cause a spectrum ofsymptoms, from minimal to severe airway compressionrequiring intervention. Vascular compression syndromes in

FIGURE 31-9 Classification of tracheoesophagealfistula. A, Atresia with upper fistula. B, Atresia with nofistula. C, No atresia, upper fistula (H type). D, Atresiawith lower fistula. E, Atresia with upper and lower fistulas.



adults are usually secondary to acquired aneurysmaldilatation of the great vessels. The radiologic evaluation ofchildren with respiratory symptoms possibly due to vascularcompression should include barium study of the esophagus,which is often affected along with the trachea by vascularrings. Contrast-enhanced CT angiography with 3D recon-structions and multiplanar reformatting is an excellentmethod of evaluating patients with complex great vesselanomalies. Alternatively, MR imaging can provide imagesof the vessels and the surrounding soft tissues.

Vascular rings are anomalies that completely encircle thetrachea and esophagus, causing airway compression. Themost common vascular ring is a double aortic arch (Fig. 31-12).26 Patients with double aortic arch typically present earlyin life with airway obstruction and often require early surgi-cal intervention. Another, less constricting, vascular ring is aright aortic arch with descending right aorta associated withan aberrant left subclavian artery and persistent ligamentumarteriosum. In both types of vascular ring, there is circumfer-ential tracheal and esophageal indentation. Other findings in-clude left-sided and anterior displacement of the distal tra-chea. Barium studies show a characteristic dorsal and left-sided impression on the esophagus.

Vascular slings are noncircumferential vascular anoma-lies that may also cause airway compromise. These

anomalies may lead to significant morbidity and occasionalmortality.26 However, vascular rings often cause moresevere airway symptoms than slings.23 In the pulmonaryartery sling, the left pulmonary artery originates from theright pulmonary artery and then passes between the tracheaand esophagus to reach the left lung. The trachea iscompressed from posteriorly, and there is an impression onthe anterior esophagus seen at barium swallow.

Anterior impression on the trachea by the innominateartery in infants and children is much more common thancompression by an aberrant left subclavian artery.27

Although most patients develop symptoms during the firstyear of life, some reported cases have presented as late as 15years of age. Symptoms include expiratory stridor, recurrentcough, apnea, and recurrent infection. Rigid bronchoscopymay establish the definitive diagnosis. In severe cases ofairway obstruction, surgical intervention is warranted.

Diffuse Disorders of the Trachea(Nonneoplastic)

Various infections and inflammations involve the tra-cheal wall. They may cause infiltration with narrowing or,less commonly, widening of the trachea.

FIGURE 31-10 Tracheoesopheagal atresia. A, Multiple attempts to pass a nasogastric tube were unsuccessful inthis full-term infant with esophageal atresia. The level of the nasogastric tube tip marks the level of the atresia. B,Chest X-ray from a different infant demonstrates a coiled nasogastric tube in the cervical esophagus, with contrastfilling the proximal esophageal pouch (arrow). This premature infant presented with copious oral secretions andnoisy respiration. Gas within the bowel indicates a distal communication between the tracheal bronchial tree and thegastrointestinal tract.



Conditions Causing Narrowing of the TracheaInfection

Laryngotracheobronchitis (croup) is the most commoninfection of the trachea. Croup is a disease of infants andyoung children, with a peak incidence between the ages of 6months and 3 years.28 Parainfluenza and respiratorysyncytial virus are the most common agents. Clinicalsymptoms include a ‘‘barking’’ cough and intermittentinspiratory stridor. Although typically infection involvesthe entire airway, critical narrowing usually occurs at theproximal 2 cm of the trachea. At this level, the trachealmucosa is relatively loose, and therefore susceptible toedema and luminal narrowing. Anteroposterior radiographsdemonstrate loss of the lateral convexities of the subglottictrachea, with luminal narrowing. This narrowing producesan inverted V configuration, with the point of the V at thelevel of the inferior margin of the true vocal cords. Thissubglottic narrowing is accentuated during expiration. Itshould be kept in mind that radiologic evaluation is notperformed to diagnose croup, but to exclude other causes ofstridor such as epiglottitis.

Bacterial tracheitis is an atypical form of croup, with aclinical picture more closely resembling that of epiglot-titis.29–31 The organisms most commonly involved areStaphylococcus aureus, group A beta-hemolytic strepto-cocci, and Haemophilus influenzae type b.29–31 Althoughearly symptoms may mimic viral croup, they do not resolvewith conventional medical therapies. The subsequent courseis typically severe, with high fever, stridor, and dyspnea withproduction of purulent sputum. Intubation or tracheotomymay be required to prevent obstruction by purulent exudate.The primary focus of inflammation/obstruction is subglottic,with sparing of the epiglottis and supraglottic structures. Thedefinitive diagnosis of bacterial tracheitis can be made bydirect inspection of the purulent exudate, which is not pre-sent in viral croup. Laryngoscopy and bronchoscopy can betherapeutic; microbiologic tests are important in confirmingthe etiologic agent and in selecting or modifying antibiotictherapy.

TuberculosisTuberculous tracheitis is rare and is usually associated

with active pulmonary tuberculosis.32, 33 The infectiontypically involves the distal trachea, where inflammationresults in irregular circumferential tracheal wall thickening,leading to narrowing or even obstruction. Areas of necrosisand ulcerations may develop. Mediastinal and hilar lymph-adenopathy are usually present. Fibrosis from chronicinflammation can lead to segmental stenosis of the tracheaand bronchi. Erosion into adjacent mediastinal structurescan lead to the development of a tracheoesophageal fistula orto severe hemorrhage from vascular invasion. Erosion ofcalcified lymph nodes into the airway can lead toexpectoration of broncholiths.34

HistoplasmosisLike tuberculosis, histoplasmosis can result in lymph

node calcification. Granulomatous lesions arise outside theairways and tend to erode into the lumen. As with

FIGURE 31-11 Recurrent tracheoesophageal fistula. A 1-year-oldinfant after repair of esophageal atresia and a distal tracheal esophagealfistula. The patient had also undergone Nissen fundoplication. Bariumswallow demonstrates recurrent tracheal esophageal fistula at the level ofthe surgical anastomosis (arrows).

FIGURE 31-12 Double aortic arch.



tuberculosis, intraluminal extension is associated withhemoptysis and expectoration of broncholiths.

Fibrosing mediastinitis is a fibroinflammatory infiltrativeprocess most commonly attributed to histoplasmosis.25, 35–38

Large masses of fibrous tissue can form in the mediastinum.The accumulated fibrous tissue can squeeze the trachea orbronchi, resulting in long areas of airway narrowing. Thepatient can present with cough, hemoptysis, or difficultybreathing. The pulmonary arteries and veins can also benarrowed, resulting in significant vascular compromise. Thelesions usually calcify and can have low signal intensity onT2-weighted images. These features may help differentiatethe lesion from an invasive malignancy. Fibrosing medias-tinitis has also been associated with tuberculosis, lymphaticobstruction, and methylsergide.

CT is the best single technique for diagnosing andassessing the severity of mediastinal fibrosis, as well as forevaluating tracheal luminal narrowing. CT studies per-formed both prior to and following the administration ofintravenous contrast may be helpful in differentiatingcalcified lymph nodes from enhancing vessels.

Mediastinal granuloma is closely related to fibrosingmediastinitis. This term describes a well-demarcated massof lymph nodes located in the mediastinum. It is commonlydiscovered as a mass lesion on routine chest radiography,typically in the right paratracheal or hilar regions. Mediasti-nal granuloma is often encapsulated and asymptomatic. Ifsymptoms are present, they relate to compression of variousmediastinal structures, including the major veins, tracheo-bronchial tree, esophagus, recurrent laryngeal nerves,pulmonary arteries, and heart. Narrowing of the tracheo-bronchial tree typically involves the major bronchi, with lessfrequent involvement of the distal trachea. Surgery is oftenindicated for diagnostic reasons (e.g., to exclude lymphoma)or for relief of specific symptoms.39

Relapsing PolychondritisRelapsing polychondritis is a rare systemic disease

characterized by recurrent episodes of inflammation, frag-mentation, and fibrosis of cartilage tissue including theears, nose, joints, and airways. Its incidence peaks in thefifth decade of life, and there is no sex predilection.39

The upper airways (larynx and trachea) are affected inmore than half of the patients. Tracheal involvement occurslate in the course of the disease. Diffuse tracheal inflamma-tion is limited to the cartilage and perichondrium, withsparing of the mucosa and submucosa.40 Respiratorymanifestations are often severe and may be life-threatening.41 Cardiovascular manifestations are present inone third of patients.

CT usually shows tracheal narrowing with diffuse wallthickening limited to the anterior and lateral tracheal walls,sparing of the posterior membrane, and narrowing of thelumen.1 When calcification is seen within the tracheobron-chial wall, the cartilage may appear thicker than normal.Both the inner and outer borders of the thickened trachealwall are smooth, and areas of tracheomalacia may coexist.Fiberoptic bronchoscopy can be useful for both directvisualization and biopsy.

Granulomatous Disease of the TracheaWegener’s granulomatosis is a hypersensitivity necrotiz-

ing granulomatous vasculitis that can involve the upper and

lower respiratory tracts and may result in tracheal stenosis. Ittypically occurs in adults, with a peak incidence in the fourthand fifth decades of life.42 Two or more organ systems maybe affected simultaneously. Pulmonary and renal involve-ment together occurs in more than two thirds of cases.43 Thekidneys are frequently affected, as are other organs such asthe skin, nervous system, eyes, ears, and heart. Trachealinvolvement typically manifests as diffuse or focal tracheo-bronchial narrowing.44 Although destruction of cartilagemay result, malacia is not typical. Dyspnea and progressiveairway obstruction develop over months or years followingthe initial diagnosis of the disease.

CT features include circumferential wall thickening withnarrowing of the tracheal lumen. Enlarged, abnormallycalcified tracheal cartilage may also be present.44 Mediasti-nal and hilar lymphadenopathy are rare thoracic manifesta-tions of Wegener’s granulomatosis.45

SarcoidosisSarcoidosis is a systemic granulomatous disease of

unknown etiology. Involvement of the lungs, mediastinallymph nodes, eyes, and skin is common. On rare occasion,the trachea can be involved.46 Sarcoidosis can lead to diffusenarrowing of the trachea and main bronchi and can causeupper-airway obstruction (Fig. 31-13). Dyspnea and coughusually result from extensive fibrosis, which causes distor-tion and narrowing of the airway. Bronchial compression bymediastinal lymph nodes and airway hyperreactivity, pre-sumably due to inflammation, contribute to the symptoms.While obstruction of the lower airway by granulomatousinfiltration and chronic pulmonary fibrosis is common,tracheal stenosis is rare.

AmyloidosisAmyloid infiltration of the airways may occur as an

isolated phenomenon or as part of a diffuse systemic disease.The focal form of amyloidosis, in which amyloid deposits ina tumor-like fashion, is usually limited to one organ or organsystem. This form can be found in approximately 10% ofcases.47 Primary solitary amyloidosis of the trachea is veryrare and has no features to differentiate it from othertumors.48 Deposition of amyloid in the submucosal andmuscular layers of the trachea and bronchi can lead totracheal narrowing and ulceration.

Tracheobronchial amyloidosis can involve the bronchialtree either as a single pseudotumorous mass or in a diffuseform.49 The diffuse form is more frequent and is character-ized by extensive subepithelial amyloid deposits. Theelevated mucosa, which forms ridges and nodules (approxi-mately 0.5 to 5 cm in diameter) that may calcify, can narrowthe tracheal lumen.2 Plain film radiographs and CT scanningdemonstrate focal or diffuse narrowing of the trachea andbronchi (Fig. 31-14). The nodular form of tracheobronchialamyloid may appear on CT as a focal mass, partially orcompletely occluding the airway. There is often infiltrationof adjacent peritracheal or bronchial tissue, frequently withcalcified foci. In this form, it may mimic the appearance ofboth benign and malignant tracheal tumors. Depending onthe size and calcification of the deposition, hemoptysis orairway obstruction may occur, ultimately resulting inatelectasis or recurrent pulmonary infection. Resection witha carbon dioxide laser and repeated bronchoscopic resectionare successful methods of treatment.39



Tracheopathia OsteochondroplasticaSubmucosal cartilaginous and/or osseous nodules charac-

terize this rare benign disease of the trachea. These nodulesproject into the lumen, causing considerable deformity. Thelesions vary in size and are located mainly in theanterolateral tracheal wall, sparing the posterior membra-nous portion of the wall.2 Most often, these lesions involvethe inferior two thirds of the trachea, and frequently extendinto the proximal portions of the major bronchi.2

The disease tends to occur in patients over 50 years ofage, with equal frequency in males and females.32 Patientsmay be asymptomatic but often present with cough,dyspnea, hemoptysis, and recurrent pneumonia. The etiol-ogy is unknown, although it has been suggested thattracheopathia osteochondroplastica develops secondary tometaplasia of the submucosal connective tissue.32

Chest radiographs may show tracheal scalloping, calci-fied nodules, or diffuse narrowing of the trachea. Thetracheal wall may be calcified. CT scan can reveal nodularthickening and irregularity of the anterior and lateral wallsof the trachea, with punctate calcification from the level ofthe thoracic inlet to the carina.50, 51 Small calcified nodulesalong the inner aspect of the tracheal cartilage protrude intothe tracheal lumen (Fig. 31-15). The differential diagnosisincludes physiologic calcification of the tracheobronchial

tree (in the elderly), tracheal amyloidosis, inflammatoryconditions, and diffuse tumorous processes. Pulmonaryfunction studies may indicate some degree of trachealobstruction. Many patients with tracheopathia osteochon-droplastica have a ‘‘saber sheath’’ tracheal deformity in theabsence of obstructive lung disease.

Saber-Sheath TracheaSaber sheath is a common variation of tracheal mor-

phology that typically affects male smokers with chronicobstructive pulmonary disease.44 Some patients with tra-cheopathia osteochondroplastica may present with thisdeformity.

The saber-sheath trachea is characterized by a markeddecrease in the transverse diameter of the intrathoracictrachea associated with an increase in its sagittal diameter.The extrathoracic trachea is normal in these cases. In itsearliest stages, narrowing is visible only at the thoracicinlet.44 In more advanced cases, the stenosis involves all orpart of the intrathoracic trachea. Saber-sheath trachea isclearly demonstrated on a CT scan obtained during forcedexpiration or a Valsalva maneuver. Inward bowing ordisplacement of the lateral tracheal walls is present and isdue to weakness of the tracheal cartilages.52

FIGURE 31-13 Sarcoid. Axial contrast-enhanced CT. A, There issoft- tissue thickening of the wall of the trachea and subglottis (arrows).B, There is precarinal (curved arrows), subcarinal (not shown), andbilateral hilar (straight arrows) lymphadenopathy in this patient withknown sarcoidosis. Mild septal thickening and centrilobular nodularityare present on the high-resolution CT images. There is also limitedhoneycombing at the right lung base, with partial atelectasis of the rightmiddle lobe. C, Calcifications are present within the lymph nodes(arrows).



Diffuse Conditions Causing Widening of the TracheaTracheobronchomegaly (Mounier-Kuhn Syndrome)

This rare condition, characterized by marked dilatation ofthe trachea and mainstem bronchi, is associated with atrophyof the cartilaginous, muscular, and elastic components of thetracheal wall. Patients commonly have associated bronchi-ectasis, with a history of recurrent pneumonia. The disease ismost commonly diagnosed in males in their third to fourthdecades of life. Patients typically have a long-standing,unusually loud, productive cough, with hoarseness anddyspnea. There is an association with other primary

connective tissue disorders, such as Ehlers-Danlos syn-drome and acquired cutis laxa.

The diagnosis of tracheobronchomegaly is made primar-ily by radiologic evaluation. On plain chest radiographs thetrachea appears enlarged, and bronchiectasis is present. CTfindings include tracheomegaly, with thinning of thetracheal wall, and a diameter of more than 3 cm below thelevel of the aortic arch or more than 2 cm above the level ofthe arch (Fig. 31-16). Tracheal scalloping or frank diverticu-losis can also be present, although difficult to appreciate oncross-sectional imaging. Three-dimensional reconstructions

FIGURE 31-14 Amyloid. A, Chest radiograph of a 65-year-old man demonstrates a diffusely thickened trachealwall on the posteroanterior view (arrows). B, T1-weighted MR image through the lower cricoid shows diffuseconcentric soft tissue (arrow) narrowing the subglottic airway. The arrowhead indicates the position of the innercortex of the cricoid cartilage. C, Axial T1-weighted image through the upper trachea shows the narrowing leaving avery narrowed airway (arrow). T, thyroid gland. D, T2-weighted axial image at the level of the lower cricoid showsthat the abnormality has very low signal (arrow).

Illustration continued on following page



may be used to display this deformity. Another commonassociation is marked tracheomalacia. There can be asignificant decrease in the diameter of the trachea onexpiration, even to the point of airway closure.

Secondary TracheomegalyChronic coughing coupled with ongoing chronic inflam-

mation has been blamed for diffuse acquired enlargement ofthe tracheal lumen. This has been described in cigarettesmokers and in patients with cystic fibrosis.

Trauma

Tracheal trauma may result from either internal orexternal injury. Internal tracheal injuries are the result ofinhalation of noxious fumes, gas, or steam or of aspiration.Edema, followed by rapid laryngotracheal airway obstruc-tion, may result from chemical or thermal injury to the

tracheal mucosa. Mechanical internal injuries are invariablydue to iatrogenic causes, such as laryngotracheal intubation.

External traumatic tracheal injuries are more commonlydue to blunt rather than penetrating trauma. The spectrum ofinjury includes small lacerations, tears of the posteriormembranous wall, fracture of the cartilaginous rings, andcomplete separation. Penetrating trauma is most often theresult of stab wounds or projectile injuries. Tracheal injuriesmost often occur in association with other severe injuries.Motor vehicle collisions are the most common cause ofblunt tracheal injuries. Although rupture of the trachea initself is a life-threatening injury, mortality is typicallycaused by damage to other surrounding vital organs.

Radiologic clues to tracheobronchial traumatic injuryinclude pneumomediastinum, subcutaneous emphysema,and pneumothorax. Other signs of tracheal injury includeelevation of the hyoid bone and distortion of the normallaryngotracheal air column.53 Anteroposterior and lateralplain films of the neck are useful in identifying free air and

FIGURE 31-14 Continued. E, T2-weighted axial image at the levelof the trachea shows the low signal (arrow) of the material infiltrating thewall within the tracheal ring (arrowhead ). F, T1-weighted sagittal MRimage reveals the thickened wall of the subglottic and tracheal airways(arrows). Note the tracheostomy tube orifice inferior to this level (thickarrow). G, T1-weighted coronal MR image also demonstrates thethickened, infiltrated wall of the subglottic and tracheal airways(arrows).



in evaluating for the presence of associated cervical spinetrauma. Plain chest radiographs are essential in theevaluation of tension pneumothorax or hemothorax. Clinicalfindings include new onset of stridor, endobronchialbleeding, and respiratory failure. Direct bronchoscopy isoften required for definitive diagnosis.47

Posttracheostomy/Postintubation ComplicationsThe increasing use of cuffed endotracheal tubes and

tracheostomy for long-term ventilation has led to character-istic injuries of the trachea. Complications from translaryn-geal intubation may lead to acute airway obstruction due topostextubation glottic edema or laryngospasm. Alterna-tively, symptoms may develop months or even years afterinjury due to glottic or tracheal stenosis.54

A portable chest radiograph should be obtained followinglaryngotracheal intubation to ensure proper positioning ofthe endotracheal tube. Ideally, the tip of the endotrachealtube should be placed well above the carina, with the headand neck in a neutral position. It is important to recognizethat flexion and extension of the neck will cause movementof the endotracheal tube of approximately 2 cm in eitherdirection. In addition, rotation of the head can cause a 1 to2 cm ascent of the tube. Unlike endotracheal tubes,tracheostomy tubes do not change position with head orneck movement, because tracheostomy tubes are notanchored to the nose or mouth.

Ideally, endotracheal tube lumens should be two thirds

the diameter of the tracheal lumen to minimize airwayresistance. Inflated tube cuffs are relatively easy torecognize on chest X-ray; their position should be checkedwhenever a chest X-ray is obtained. The inflated cuff shouldfill, but not bulge, the tracheal lumen. Rigid low-volume

FIGURE 31-16 Tracheomegaly. Nonenhanced axial CT scan, ob-tained at three levels in the upper thorax, demonstrates marked dilatation ofthe trachea in this patient with recurrent pneumonia. Note that above thelevel of the aortic arch, the tracheal diameter is greater than 2 cm.

FIGURE 31-15 Tracheopathia osteochondroplastica. A and B,Nonenhanced axial images from a CT scan of the upper thoraxdemonstrate osseous nodules and thickening of the anterior and lateralwalls of the trachea (A, white arrows, B, black arrow), with sparing ofthe posterior membranous tracheal wall. Note the involvement of theproximal right mainstem bronchus on C (black arrow). (Courtesy of Dr.Theresa McLoud, Boston.)



cuffs have been replaced by high-volume, low-pressurecuffs, which are significantly more compliant and thereforeadapt better to the variable cross-sectional shape of thetracheal lumen.2 Most importantly, these newer cuffsprovide sufficient sealing at approximately one tenth of thepressure required for rigid cuffs (about 20 to 30 mm Hg).Tracheal narrowing at the cuff site has dramaticallydecreased in frequency since the introduction of these high-volume, low-pressure cuffs. Immediate complications fol-lowing laryngotracheal intubation can result from insertionof the tube into the right mainstem bronchus or positioningof the tube tip too close to the carina. The risk of aspiration issignificantly increased if the cuff is malpositioned in thevocal cords or within the pharynx. In addition, overdisten-tion of a malpositioned cuff may lead to vocal cord necrosis.Early complications of tracheostomy are usually associatedwith abnormal anterior, posterior, or lateral angulation of thetube. This can result in increased airway resistance,

difficulty in clearing of secretions, or, if persistent, erosionor perforation of the tracheal wall. Anterior perforation mayresult in trachea-innominate artery fistula, whereas posteriorperforation may lead to tracheoesophageal fistula.55

Late tracheostomy and postintubation stenosis can occurat the tracheostomy opening (stoma), at the balloon cuff site,or, rarely, where the tip of the tube abuts the trachealmucosa. Most long-term complications are due to pressurenecrosis at the cuff site.44 When cuff pressure exceedscapillary pressure, the blood supply to the tracheal mucosa iscompromised and ischemic necrosis results.44 At first, themucosa overlying the tracheal cartilages undergoes pressurenecrosis. If the cuff is removed at this point, cicatricialhealing usually results in an anterior tracheal web/scar. Theflexible posterior wall is uninvolved. However, with greatercuff pressure, the posterior wall is also affected and acircumferential scar is produced. Usually this type oftracheal damage is limited to one or two tracheal rings at thelevel of the cuff-related injury (Figs. 31-17 to 31-22).Radiographically, the stenosis has a smooth edge. Typically,symptoms of stenosis develop 2 to 6 weeks postextubationand, in some patients, months or even years later.44 Stenosisat the tracheostomy stoma may be prevented by improved

FIGURE 31-17 Resected specimen of a trachea (seen from behind)from a patient with cuffed tube injury. Hyperemic mucosa remainsbetween the paler denuded tracheal cartilages. The mucosa overlying thesecartilages is the first area damaged by the inflated cuff.

FIGURE 31-18 Resected specimen from a patient with cuffed tubetracheal injury. The scarred segment involved only the area overlying therigid tracheal cartilages. This earlier type of stenotic injury has a semilunarconfiguration. The membranous posterior tracheal wall is not involved.

FIGURE 31-19 Resected specimen from a patient with cuffed tubetracheal injury. There is circumferential involvement of the trachea in thismore advanced type of injury. The membranous posterior wall and themucosa overlying the tracheal rings are involved.

FIGURE 31-20 Axial contrast-enhanced CT scan shows a normaltracheal lumen at the level of the uppermost trachea.



surgical technique, control of local infection, and avoidanceof heavy connecting equipment.56

Granuloma formation at the tracheostomy site is alsocommon. Often on CT, such a granuloma is seen as a smallincidental soft-tissue mass on the anterior tracheal wall. Thedifferential diagnosis is with dessicated secretions at thetracheostomy site.

The configuration of the trachea is often altered after tra-cheostomy. Interruption of the integrity of the involvedtracheal cartilages often identifies the site of a prior tracheos-tomy (Fig. 31-23). Side-to-side collapse of the anterior tra-cheal configuration can also result from loss of support fromthe violated tracheal rings (Fig. 31-24).

Resection of the stenotic segments with anastomosis istraditionally the treatment of choice for tracheal stenosisfollowing extubation, provided that the stenotic segmentdoes not exceed two or three tracheal rings. Polyurethane-covered, retrievable, expandable Nitinol stents are currentlyunder investigation as a relatively new method for thetreatment of tracheal strictures (Fig. 31-25). In cases ofinoperable tracheal strictures with resultant dyspnea, these

stents are suggested to be a safe and convenient nonsurgicalalternative.57

Other less common long-term complications of intuba-tion include tracheomalacia and ulcerative tracheoesoph-ageal fistula. When an indwelling esophageal tube is usedalong with intubation, particularly in neurologically im-paired patients who are ventilated for long periods of time,tracheoesophageal fistula may result. The mechanism ofinjury is pressure necrosis resulting from the pressureexerted by the cuff on the tracheal wall abutting a foreignbody within the esophagus. This type of fistula often resultsin recurrent pneumonia.

Tracheal Tumors

General ConsiderationsPrimary tumors of the trachea are rare, with malignant

neoplasms representing only 2% of all upper airwaytumors.58 These tumors include primary epithelial andmesenchymal neoplasms, as well as secondary neoplasiadue to either metastases or, more commonly, direct trachealinvasion from adjacent mediastinal neoplasms. In adults,primary tumors are most commonly malignant, whereas inchildren, benign tumors are more likely.59

FIGURE 31-21 Axial contrast-enhanced CT scan shows a semilunartracheal stenosis corresponding to the type of injury shown in Figure31-18. The tracheal cartilages in this patient were poorly calcified.

FIGURE 31-22 Axial contrast-enhanced CT scan shows a circumfer-ential tracheal stenosis corresponding to the type of injury shown in Figure31-19. The thyroid gland surrounds the anterior and lateral aspects of thetrachea.

FIGURE 31-23 Axial contrast-enhanced CT scan shows separation ofthe anterior tracheal cartilage at the site of a prior tracheostomy.

FIGURE 31-24 Axial contrast-enhanced CT scan shows a side-to-sidecollapse of the tracheal cross-sectional airway configuration due to injuryof the tracheal cartilage from a prior tracheostomy.



Adult tracheal tumors occur between the third and fifthdecades of life, with no sex predominance. Most occur atthe distal third of the trachea.58 Symptoms associatedwith tracheal tumors include dyspnea, cough, hemoptysis,new-onset asthma or wheezing, dysphagia, stridor, changein voice and/or hoarseness, recurrent pneumonia, andemphysema. Approximately one third of patients withtracheal tumors are initially mistakenly treated for asthmaticbronchitis.44

Malignant TumorsThe most common malignant tracheal tumor in adults is

squamous cell carcinoma, followed by adenoid cysticcarcinoma. Together, these two neoplasms account for up to86% of all malignant adult tracheal tumors.1 Secondarymalignant tumors are due to either metastases or directtracheal invasion by adjacent mediastinal neoplasms. Themost common primary carcinomas that spread directly to thetrachea are from the lung, thyroid, or esophagus (Fig.31-26).1 The most common carcinomas to metastasizehematogenously to the trachea are breast, gastrointestinal,melanoma, lymphoma, renal cell carcinoma, or squamouscell carcinomas of the head and neck.60, 61

Squamous Cell CarcinomaSquamous cell carcinoma (SCC) is the most common

primary malignancy of the trachea. It typically affectsmiddle-aged male smokers (mean age, 50 to 60 years).2 SCCis associated with other malignant neoplasms of therespiratory and digestive tracts in one third of patients. Therelatively high incidence of synchronous or metachronoustumors, found most frequently in the larynx, lung, oresophagus, makes comprehensive evaluation and follow-upimaging of the entire respiratory tract essential. AlthoughSCC may arise at any level in the trachea, the lower trachea

and the carina are the most common locations (Fig. 31-27).58

At the time of presentation, the tumor is frequently locallyadvanced, with extension into the major bronchi andmediastinum.58, 62 Malignant tracheoesophageal fistula canresult from such extension. Lymph node metastases aregenerally seen in later disease stages, with distant metastasesuncommon (Fig. 31-28). Patients may present with cough,dyspnea, hemoptysis, wheezing, stridor, and recurrentpneumonia.2 The development of hoarseness usually indi-cates infiltration of the recurrent laryngeal nerve. Theprognosis of patients with SCC is poor, with 5-year survivalreported to be between 10% and 30%.2

Radiologic findings include focal and/or circumferentialirregular thickening of the tracheal wall with luminalnarrowing (Fig. 31-3). CT is useful in demonstrating theprimary tumor, as well as extension of tumor intosurrounding structures.44

Adenoid Cystic CarcinomaAdenoid cystic carcinoma (ACC) is the second most

common primary tracheal malignancy. Unlike SCC, there isno definite association with cigarette smoking, and thetumor occurs with equal frequency in males and females.The peak incidence of ACC is about 10 years earlier than inpatients with SCC.58 ACC arises from the tracheobronchialmucous glands and is usually located on the posterolateralwall of the trachea.1 It is composed of small epithelial cellsarranged in sheets, with fenestrations that produce acribriform pattern. The tumor is a low-grade malignancythat tends to invade insidiously the submucosal plane of thetrachea.44 Occasionally, circumferential involvement of thetrachea and bronchus without a distinct mass can be seen.ACC infiltrates through the fibrous membrane betweenadjacent cartilage plates and into surrounding tissues in theneck and mediastinum.63 There may be perineural, intra-

FIGURE 31-25 Tracheal stent. A 30-year-old male who suffered from an accidental pistol discharge wasintubated for 20 days. Approximately 1 week following extubation, he developed difficulty breathing and was foundto have granulation tissue causing tracheal stenosis. A covered tracheal stent was placed, providing relief ofsymptoms. A, Pre-stent AP chest X-ray shows narrowing of the subglottic airway above the level of thetracheostomy (arrow). B, Anteroposterior view of the chest following stent placement demonstrates the coveredtracheal stent extending from the subglottic trachea to approximately 3 mm above the carina.



neural, or pericardial great vessel involvement.60 Indeed,perineural spread of tumor is a distinctive characteristic ofACC. ACC spreads to cervical and mediastinal lymphnodes in 10% of patients.58 Involvement of the larynx or therecurrent laryngeal nerve may result in restriction of vocalcord motion. Hematogenous metastases spread most com-monly to the lungs, with occasional spread to the brain orbony skeleton.63

ACC appears on radiographs as either a broad-based orpedunculated polypoid lesion. There may be smooth ornodular thickening of the tracheal wall, with associatedluminal narrowing.44 Barium swallow may demonstrateextrinsic esophageal compression or invasion. CT is usefulin demonstrating the primary tumor and its extent (Fig.31-29). However, because ACC may grow in the submuco-sal planes without producing a distinct mass, CT mayunderestimate the true extent of tumor.

The treatment of ACC involves surgical resection andanastomosis when possible. When surgical resection isperformed, frozen section pathologic evaluation of thebiopsy margins is recommended. Radiation therapy is usedwhen surgery is not indicated. ACC has the best prognosisamong the malignant tracheal neoplasms.2 About 75% of

patients are free of disease 5 years after therapy, but laterecurrence, or survival with locally recurrent tumor forperiods of 10 to 15 years, is common.64, 65

Mucoepidermoid CarcinomaMucoepidermoid carcinoma is a rare tumor that can

occur as either a low-grade or a high-grade malignancy. Thetumor arises from the minor salivary glands lining thetracheobronchial tree and consists of mucus-secreting cells,squamous cells, and intermediate cells that have noparticular differentiating characteristics.

Mucoepidermoid carcinoma has been reported in patientsranging in age from 4 to 78 years, but nearly 50% of patientsare under the age of 30.66 The most common presentingsymptoms relate to airway irritation (cough or hemoptysis)or obstruction (wheezing or pneumonia).66 In its low-gradeform, mucoepidermoid carcinoma grows slowly, is noninva-sive, and therefore rarely metastasizes.67 Completely resect-able low-grade tumors have an excellent prognosis, andthese patients rarely have tumor recurrence. Even in itshigh-grade form the tumor is slow-growing and has a betterprognosis than do the more common bronchogenic carcino-mas. In one study,68 only 15% of high-grade mucoepider-

FIGURE 31-26 Carcinoma of the thyroid. Anterior (A) and lateral (B) conventional X-ray tomographicprojections, as well as lateral plain film view of the neck (C), demonstrate a focal impression on the anterior leftlateral wall of the trachea caused by an extrinsic thyroid carcinoma (B, arrow). The tracheal lumen is reduced to lessthan half of its normal width in the anteroposterior dimension.



moid carcinomas metastasized to regional lymph nodes. Thetumor may manifest as a polypoid mass in the lumen of amain, lobar, or segmental bronchus. Radiographs maydemonstrate a solitary pulmonary nodule or postobstructive‘‘pneumonic consolidation.’’68 CT scans may reveal punc-tate calcification within a smoothly oval or lobulated, mildlyenhancing intraluminal mass (Fig. 31-4). The incidence ofintratumoral calcification—up to 14%—is much higher thanthat of other pulmonary carcinomas.12

ChondrosarcomaTracheal chondrosarcoma is an extremely rare neoplasm

with an excellent prognosis. The tumor is typically locatedin the middle to distal trachea. It grows slowly, expandingboth into and away from the airway. Tracheal resection isthe treatment of choice.

CT demonstrates a stereotypical soft-tissue mass withcoarse or stippled calcifications. The hyaline tumor matrix ischaracterized by high signal intensity on T2-weighted im-ages due to its high water content and low cellularity.The stippled calcifications are not as well seen on MR imag-ing studies as on CT, but they may appear as areas of lowsignal intensity on T1- and T2-weighted sequences. The dis-tinction between benign chondroma, a nonmalignant form ofchondroid tumor, and low-grade chondrosarcoma may beimpossible on the basis of imaging studies alone.13, 69

Benign TumorsBenign tumors of the trachea are rare and occur most

frequently in children, in whom they account for 90% ofprimary tracheal neoplasms.44 Squamous cell papilloma,fibroma, and hemangioma are the most common benignchildhood tracheal neoplasms.70 Other benign trachealtumors include granular cell myoblastoma,71 cartilaginoustumors,61 neurilemmoma, lipoma, fibrous histiocytoma,intratracheal goiter, benign mixed tumor, and leiomyoma.60

Benign tracheal tumors tend to have a smooth contourand usually are less than 2 cm in size.60 Presentingsymptoms include cough, dyspnea, wheezing, recurrentpneumonia, and hemoptysis.2 Chest X-ray can show trachealluminal narrowing, postobstructive atelectasis, or tumorcalcification. Because of their benign nature, benigntracheal tumors are usually well-circumscribed, sometimeslobulated intraluminal tumors, with limited spread into thetracheal wall (Fig. 31-30).60 CT with 3D multiplanarreconstructions for surgical planning can delineate theprecise location and extent of the mass. Calcification istypically present in cartilaginous-based lesions, includingchondromas, low-grade chondrosarcomas, chondroblasto-mas, and hamartomas. Lipomas are hypodense on CTscanning, whereas they have increased signal intensity onT1-weighted and intermediate signal intensity on T2-weighted MR imaging exams.60

FIGURE 31-27 Recurrent squamous cell carcinoma at the carina. A 48-year-old male after pneumonectomy forSCC of the lung presented with cough and sputum production. Contiguous contrast-enhanced axial chest CT imagesdemonstrate soft-tissue infiltration anterior to and to the left of the distal trachea extending to the carina (arrows).Irregularity of the anterior tracheal wall, carina, and left mainstem bronchus is indicative of neoplastic invasion.Postpneumonectomy changes are noted.



Benign Vascular TumorThe most common benign pediatric large airway tumor is

the hemangioma.33 It is typically located in the subglotticportion of the larynx (i.e., subglottic hemangioma), not in

the trachea. The cavernous form of hemangioma occursmore commonly than the capillary form. Neonates withairway hemangioma usually become symptomatic, withstridor and cough, within 3 months of birth.33 Symptomsvary depending on the degree of vascular engorgement.These lesions rarely occur independently of other associatedcongenital vascular lesions such as hemangiomas of theskin, parotid gland, mediastinum, abdominal viscera, centralnervous system, and retina. Because these lesions have acharacteristic bronchoscopic appearance, biopsy is unneces-sary and indeed may result in severe hemorrhage. Becausemany of these tumors regress spontaneously, the treatmentof choice for both children and young adults is observation.For larger masses, temporary tracheostomy may be neces-sary for airway preservation. If the mass persists, trachealresection may become necessary.

Hemangioendothelioma is an extremely rare lesionrepresenting the benign counterpart of malignant heman-gioendotheliosarcoma. This slow-growing tumor appears asa solid polypoid mass and contains endothelial cellssurrounded by microscopic vascular channels.72

Squamous Cell PapillomaThe most common adult benign tracheal neoplasm is

squamous cell papilloma. These tumors most often occur inmiddle-aged male smokers and typically involve the larynxor bronchi rather than the trachea. Squamous cell papillomais characterized by single or multiple sessile or papillarynodular masses, with a central fibrovascular core and layers

FIGURE 31-28 Hematogenous metastases. A 48-year-old malepresented with a 3-month history of 40-pound weight loss, chronic cough,malaise, and drenching night sweats. A 5 cm diameter poorly differentiatedSCC with necrosis was discovered in his distal trachea. T1-weightedpostgadolinium MR image through the posterior fossa demonstrates a3.5 cm diameter cystic mass with ring enhancement and internal septation.There is a slight mass effect on the fourth ventricle (left). AxialT1-weighted postgadolinium image at a more superior level (right)demonstrates an enhancing mass in the left occipital lobe (large arrow)with surrounding edema, as well as a small enhancing mass in the medialleft temporal lobe (small arrow).

FIGURE 31-29 Adenoid cystic carcinoma. A, Chest radiograph demonstrates a large, broad-based endoluminalmass arising from the right tracheal wall (arrows) and partially obstructing the tracheal lumen. B, Axialnonenhanced CT scan demonstrates this large, lobulated, low-attenuation endoluminal mass arising from the righttracheal wall at the level of the thoracic inlet (arrow). Tumor is seen along the outer wall of the calcified cartilage aswell, indicating infiltration either through or between the tracheal cartilages.



of well-differentiated squamous epithelium (Fig. 31-31).Papillomas tend to recur after resection and may undergomalignant degeneration.

Laryngotracheobronchial papillomatosis is a conditionassociated with multiple papillomas. Although histologi-cally similar to solitary papillomas, the lesions associatedwith this condition more often occur in young children andtend to regress spontaneously after puberty.58 Tracheobron-chial papillomatosis results from a multicentric infection bythe human papilloma virus. The disease is commonlyacquired at birth as the infant passes through a birth canalinfected with cervical condylomata. Papillomatosis has alsobeen noted to occur in patients with the acquired immunedeficiency syndrome (AIDS).1 Although papillomatosis isusually restricted to the larynx, in a minority of patients oneor more papillomas may develop in the trachea or bronchi,which can cause airway obstruction leading to atelectasisand bronchiectasis. Papillomas rarely spread to the lung,appearing on plain chest radiographs or CT scans as multiplesmall, widely scattered, round pulmonary nodules, whichfrequently develop thin-walled cavities with air-fluid levels(Fig. 31-32).73 Clinically, laryngeal disease presents withhoarseness, whereas tracheobronchial disease presents withwheezing, atelectasis, or recurrent pneumonia. Asymmetrictracheal or bronchial wall thickening, causing eccentrictracheal luminal narrowing, may also be present.

Cartilaginous Tumors and HamartomasCartilaginous tumors of the larynx and trachea are rare

and include hamartoma, chondroma, and their malignantcounterpart (already discussed), chondrosarcoma. Chondro-mas occur with equal frequency in males and females andare most common during the fourth to sixth decades.61

These tumors present as sharply defined masses arising fromthe tracheal cartilage. They vary in size from very small,causing only a slight convexity of the endotracheal surface,to very large, forming an extensive mass.61 They are usuallylocated in the upper trachea.58 The mucosa overlying theseregions is usually intact, and calcification may be evident onchest radiographs and CT scanning. Distinction of chon-droma from low-grade chondrosarcoma is controversialeven at pathologic examination. The lesions in this area tendto grow slowly, and metastasis is rare.

A hamartoma is defined pathologically as a ‘‘tumor-likemalformation composed of an abnormal combination of thenormal constituents of the organ in which it is found.’’61

Most endobronchial hamartomas therefore contain massesof cartilage, fat, or cystic fluid collections, with clefts linedby bronchial epithelium. They grow slowly and are usuallysolitary. The average age at presentation is 45 to 50 years.These tumors can be pedunculated; consequently, onelesion can obstruct different bronchi at different times.Clinical manifestations include bronchial obstruction or

FIGURE 31-30 Glomus tumor. An 86-year-old male with episodic shortness of breath, cough, and hemoptysis.Rigid bronchoscopy and biopsy revealed multiple tracheal nodules and tracheal thickening. Biopsy demonstratedglomus tumor. Sagittal reconstruction of a contrast-enhanced CT scan demonstrates a tracheotomy tube that extendsto the level of the transverse aorta (upper left corner). Diffusely thickened soft tissue with nodular componentsencases the trachea (remaining panels).



occasionally hemoptysis. These tumors nearly alwaysmanifest stippled calcification, although clear-cut calcifica-tion is detected on plain films in 10% to 15% of patients inmost series.74 If calcification is of the typical ‘‘popcorn’’configuration of cartilage calcification, the diagnosis ofharmatoma is virtually certain. The contrast resolution ofCT scanning improves the ability to identify calcium and fatwithin these lesions. Surgical excision is the treatment ofchoice.

Carcinoid TumorCarcinoid tumors of the trachea characteristically infil-

trate the tracheal cartilage, growing slowly in a dumbbellconfiguration. The age range at presentation is variable, butthe peak incidence is in the fifth to sixth decades. Theatypical form of bronchial carcinoid has cellular and clinicalfeatures intermediate between those of typical carcinoid andSCC.75 All types of carcinoid tumors are of neuroendocrineorigin and are thought to form a spectrum of varying degreesof malignancy. Because these tumors are vascular, hemopty-sis is a common presenting complaint. Other presentingsymptoms include cough, pneumonia, atelectasis, andwheezing. The tumor may be predominantly intraluminal,assuming a polypoid configuration, or predominantlyextraluminal (an ‘‘iceberg’’ lesion). Calcification and/orossification within the tumor may occur.76 Cushing’ssyndrome may develop due to secretion of corticotropins bytumor cells, and carcinoid syndrome uncommonly occursas a complication of carcinoid tumor.77 CT scanningprovides superb anatomic localization of both the intralumi-nal and extraluminal components of the tumor. CT also mayidentify calcification and enhancement within the tumor.

Recurrence of carcinoid tumor is a significant problem,

particularly after surgical resection of pedunculated tumors.Other methods of treatment, such as fulguration, cryother-apy, and laser ablation, seem to reduce recurrence rates morethan local bronchoscopic resection.

Benign Mixed Cell TumorsBenign mixed cell tumors (pleomorphic adenomas) of the

trachea are histologically similar to benign mixed tumors ofthe major salivary glands. These contain a mixture ofepithelial cells, cartilaginous elements, and mesenchymalcells. Although these lesions are less commonly found intracheal or bronchial minor salivary glands than in majorsalivary glands, they constitute the fifth most common typeof benign tracheal mass. Treatment consists of completeexcision; recurrence is unusual.

Tumor-Like Conditions

Many nonneoplastic diseases can present as tracheal orbronchial masses. Infectious diseases such as tuberculosis,systemic histoplasmosis, or even coccidioidomycosis canform intraluminal granulomas that may simulate primarytumors. Traumatic injury of the trachea can also incitegranuloma formation. Occasionally, aspirated foreign bod-ies may adhere to the tracheal wall and simulate tumor.Cysts and mucoceles in children must be differentiated fromcommon tumors such as hemangiomas and fibromas.

Ectopic thyroid tissue in the trachea, although rare, cansimulate neoplastic disease. Ectopic thyroid tissue is foundin 1 of 7000 to 18,000 patients who undergo thyroid glandsurgery (with a female predominance). It may come toclinical attention due to growth of normal thyroid tissue,

FIGURE 31-31 Squamous papilloma. Lateral chest radiograph (A) and noncontrast axial chest CT (B)demonstrate a polypoid endoluminal mass (B, short arrow, A, long arrow) protruding from the posterior left lateralwall of the midtrachea just above the level of the aortic arch.



FIGURE 31-32 Tracheal papillomatosis. A, Anteroposterior chest radiograph demonstrates multiple exophyticmasses projecting into the tracheal lumen (arrow). B, Coronal plain film tomography demonstrates multiplepolypoid masses arising from the tracheal wall (arrowheads ). C, Axial contrast-enhanced CT scan through themidtrachea demonstrates multiple pedunculated and broad-based exophytic polypoid masses arising from thetracheal wall (arrows).

FIGURE 31-33 Substernal thyroid. Axial contrast-enhanced CT scanreveals an enlarged thyroid gland extending inferiorly to the level of, andposterior to, the sternum (arrow). There is mass effect on the trachea,which is compressed and displaced toward the right.

FIGURE 31-34 Goiter. A 75-year-old man with hyperthyroidism.Contiguous contrast-enhanced axial images from a CT scan demonstrate a4 × 5 cm diameter left thyroid mass (arrow), which flattens and deviatesthe trachea toward the right. An adenomas goiter was discovered followingpartial thyroidectomy.



goitrous enlargement, or malignant degeneration (Fig.31-33). A characteristic location is 2 to 3 cm below the vocalcords, although it may present more distally in the trachea.Frequently, intratracheal goiter is associated with goitrousenlargement of the normally positioned thyroid gland (Fig.31-34). Intratracheal thyroid tissue may manifest years afterthyroidectomy because of compensatory hyperplasia. Surgi-cal resection is recommended, as malignant degenerationoccurs in 10% of cases.

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chapter 31 trachea: anatomy and pathology · visibility of the bony thorax and improves imaging of...

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