Carotid Body Tumour

Dr. Maha Al Marashi

KM. 34 Female

Elective admission for Right Carotid body tumour excision

Had been referred initially to the vascular service with bilateral carotid body tumours

Incidental finding with no local pressure symptoms or systemic effects

KM. 34 Female

BGHx: Left carotid body tumour embolizaion Appendectomy as a child Tonsillectomy as a child

KM. 34 Female

Medications: Nil

Allergies: Nil

KM. 34 Female

Family Hx: Grandfather – Carotid body tumour Brother – Carotid body tumour bilaterally

KM. 34 Female

Ultrasound scan neck Evidence of bilateral

carotid body tumours of the carotid bifurcation consistent with carotid body tumours.

Thyroid gland is normal. No other abnormalities.

KM. 34 Female

Duplex scan of carotids Bilateral masses in the

region of the carotid body at the bifurcation of the internal and external carotids. Right is smaller and more

vascular. Left encases vasculature.

KM. 34 Female

Genetic screening:

KM. 34 Female

Right carotid body tumour excision

KM. 34 Female

Histology:

KM. 34 Female

Discharged home day 2 post op with no complications

Simple analgesia and aspirin For OPD follow up in 4 weeks.

Carotid body tumours

Anatomy

Bifurcation of the common carotid artery

Right side coming of the brachiocephalic artery

Left side from arch of aorta

Anatomy

1. Thyroid gland

2. Trachea

3. Brachiocephalic artery

4. Common carotid artery

5. Internal jugular vein

6. Superior vena cava

Embryology

Derived from: Mesodermal elements of the third branchial arch Neural elements originating from the neural crest

ectoderm

Neural crests differentiate into forerunners of paraganglionic cells Paragangangliomas

Physiology

Chemoreceptors located in the bifurcation of the common carotid artery

Monitor changes in the oxygen and CO2 content and pH of the blood and rely that sensory information to the hypothalmus and brain stem to help them control cardiovascular and respiratory functions

Other cells in the carotid body respond to blood temperature and to certain chemicals, e.g., nicotine and cyanide.

Has extremely high blood flow and oxygen consumption

Histology

Resemble the normal architecture of the carotid body

Highly vascular Zellballen (cell nests) “Sustentacular” cell Epithelioid cell

Cytochemical techniques have demonstrated: Adrenaline Noradrenaline Serotonin

Classification

Chromaffin Capable of producing catecholamines

Non-chromaffin

Initially, Carotid body tumours were thought to be non-chromaffin paragangliomas

≤5% of carotid body tumours are endocrinologically active

May be part of the neurocristopathies e.g. MEN 1 & 2 Secondary tumours are common, including

phaeochromocytomas

Pathology

Only known pathology is neoplasia Most common of the non-chromaffin

paragangliomas

Shamblin et al described the following anatomic groups:

1. Group 1: small tumours, minimally attached. Surgical excision not difficult

2. Group 2: larger, moderate attachments. Can be resected, but many require temporary intra-luminal carotid shunt

3. Group 3: very large, encase carotid arteries. Often require arterial resection and grafting

Incidence

Sporadic More common 5% incidence of bilateral tumours

Familial Autosomal dominant 32% incidence of bilateral tumours Men:Women = 1:1 Screening of family members recommended

Age Range between 20-80 Most apparent in 5th decade

Biologic behaviour

Malignant potential Cannot be predicted by histological markers Made by presence of lymph nodes or metastases

Metastatic spread In region of lymph nodes Kidney, thyroid, pancreas, cerebellum, lungs, bones, brachial

plexus, abdomen and breast Rate approximately 5%

Predictors Severity of symptoms Size at time of diagnosis

History

Painless swelling in neck at the angle of the mandible Non-specific

Neck or ear pain Local tenderness Hoarseness Dysphagia Tinnitus

Occasionally Cranial nerve dysfunction

Rarely Lateralizing central neurological signs or symptoms

Neurosecretory Dizziness Flushing Palpitations Tachycardia and arrhythmias Headache and photophobia Diaphoresis

Examination

Neck mass below the angle of the mandible Laterally mobile but vertically fixed Non-tender, rubbery, firm and non-compressible Often pulsatile Bruit Abnormalities caused by vagal or hypoglossal nerve

impingement Horner’s syndrome (rare) Palpate opposite side

Differential diagnosis

Lymphoma Metastatic tumours Carotid artery

aneurysm Thyroid lesions Submandibular salivary

gland tumours Branchial cleft cysts

Investigations

Duplex scan with colour flow imaging Documents the highly vascularised mass in the area of carotid bifurcation Tumour dimensions Co-existent carotid occlusive disease

Angiography Gold standard Identifies collaterals, concurrent atherosclerosis and multicentric disease

Dynamic or rapid sequencing CT Differentiates between aneurysm and neoplasm Size and extent

MRI Demonstrates relationship of tumour to adjacent structures Differentiate from other soft tissue lesions at base of skull Size and extent

Management

Mainstay is complete surgical excision due to: ≥5% incidence of metastases Unrelenting growth of unresected tumours

Early excision decreases incidence of cranial nerve and carotid artery damage Most are in Shamblin’s group 2 or 3 at time of clinical

presentation Radiation for local control of residual or recurrent disease Chemotherapy has no role Pre-operative embolization

Pros: Decrease vascularity and improve safety Cons: thrombosis of ICA or cerebral embolization

Prognosis

Carotid body tumours are slow growing and exhibit benign characteristics

Can survive for long periods without surgical intervention

Death due to asphyxia and intra-cranial extension; Martin et al noticed death rate of approximately 8% in untreated patients

Even after prolonged disease-free intervals, local recurrence following surgical resection described

THANK YOU