Imaging of Renal Imaging of Renal Neoplasms in Infants Neoplasms in Infants

and Childrenand ChildrenJason Coryell, MS4Jason Coryell, MS4

March 31, 2006March 31, 2006

Guiding principlesGuiding principles Ultrasound is a standard first-line modalityUltrasound is a standard first-line modality; ;

CT and MRI often are used to delineate extent CT and MRI often are used to delineate extent of diseaseof disease

Different tumor types share radiographic Different tumor types share radiographic features; features; histologic diagnosis is the gold histologic diagnosis is the gold standardstandard

Trends based on age, distribution of metastases, Trends based on age, distribution of metastases, and appearance aid radiographic differentiationand appearance aid radiographic differentiation

Categorical approaches include age (infancy vs Categorical approaches include age (infancy vs childhood), severity (benign vs malignant), and childhood), severity (benign vs malignant), and structure (solid vs cystic)structure (solid vs cystic)

Distribution by ageDistribution by age InfancyInfancy

NephroblastomatosNephroblastomatosisis

Mesoblastic Mesoblastic nephromanephroma

Wilms' (less Wilms' (less frequent)frequent)

RhabdoidRhabdoid Ossifying renal Ossifying renal

tumor of infancytumor of infancy

ChildhoodChildhood Wilms'Wilms' Clear cell sarcomaClear cell sarcoma Renal cell Renal cell

carcinomacarcinoma Multilocular cystic Multilocular cystic

nephromanephroma AngiomyolipomaAngiomyolipoma Lymphoma (NHL)Lymphoma (NHL) Renal medullary Renal medullary

carcinomacarcinoma Rhabdomyosarcoma Rhabdomyosarcoma

(pelvis)(pelvis)

Distribution by severityDistribution by severity

BenignBenign NephroblastomatosNephroblastomatos

isis Mesoblastic Mesoblastic

nephromanephroma Multilocular cystic Multilocular cystic

nephromanephroma AngiomyolipomaAngiomyolipoma Ossifying renal Ossifying renal

tumor of infancytumor of infancy

MalignantMalignant Wilms'Wilms' Clear cell sarcomaClear cell sarcoma Renal cell Renal cell

carcinomacarcinoma RhabdoidRhabdoid LymphomaLymphoma Renal medullary Renal medullary

carcinomacarcinoma RhabdomyosarcomaRhabdomyosarcoma

Wilms' tumorWilms' tumor

a) US demonstrates exophytic tumor of lower pole

c) Contrast enhanced CT-well-circumscribed, lobulated, heterogeneously enhancing exophytic mass extending from superior pole of L kidney

d) CT Coronal reconstruction in same patient

e) MRI of same patient (Wilms' is variably hyperintense on T2 images)

Epidemiology of Wilms' Epidemiology of Wilms' tumortumor

Account for 90% of pediatric renal tumorsAccount for 90% of pediatric renal tumors Peak incidence = 3 years (<1-10)Peak incidence = 3 years (<1-10) Most often sporadic and unilateralMost often sporadic and unilateral

1% familial (16% of familial cases are 1% familial (16% of familial cases are bilateral)bilateral)

10% bilateral (2/3 synchronus, 1/3 10% bilateral (2/3 synchronus, 1/3 metachronus)metachronus)

Increased risk for Wilms' with persistence of Increased risk for Wilms' with persistence of embryonic renal tissue (nephrogenic rests = embryonic renal tissue (nephrogenic rests = nephroblastomas)nephroblastomas)

Wilms' tumor Wilms' tumor associationsassociations

Molecular Associations-2 known tumor suppressor genes on Molecular Associations-2 known tumor suppressor genes on chromosome 11chromosome 11 WT-1-assoc w/ WAGR (Wilms, aniridia, GU anomalies, retardation)WT-1-assoc w/ WAGR (Wilms, aniridia, GU anomalies, retardation) WT-2-loss of heterozygosity associated with Beckwith-WiedemannWT-2-loss of heterozygosity associated with Beckwith-Wiedemann

Associated conditions: Associated conditions: Beckwith-Wiedemann (omphalocele, gigantism, macroglossia)Beckwith-Wiedemann (omphalocele, gigantism, macroglossia) hemihypertrophy, hemihypertrophy, Denys-Drash (pseudohermaphroditism, glomerulonephritis)Denys-Drash (pseudohermaphroditism, glomerulonephritis) sporadic aniridia (1/3 develop Wilms')sporadic aniridia (1/3 develop Wilms') Sotos (cerebral gigantism),Sotos (cerebral gigantism), Bloom syndrome (facial telangiectasias, GI tumors)Bloom syndrome (facial telangiectasias, GI tumors) Perlman syndrome (visceromegaly, gigantism, cryptorchidism)Perlman syndrome (visceromegaly, gigantism, cryptorchidism)

Recommended US screening every 3-6 months for first 7 years; Recommended US screening every 3-6 months for first 7 years; however, of uncertain benefit in overall survivalhowever, of uncertain benefit in overall survival

15% of WT pts have other GU anomalies (cryptorchidism, 15% of WT pts have other GU anomalies (cryptorchidism, horseshoe kidney) horseshoe kidney)

Wilms' tumor Wilms' tumor morphologymorphology

Large, spherical masses (avg Large, spherical masses (avg 12 cm at dx) with 12 cm at dx) with pseudocapsule of pseudocapsule of compressed parenchymacompressed parenchyma

Heterogeneous density Heterogeneous density (hemorrhage, fat, necrosis, (hemorrhage, fat, necrosis, and/or calcification)and/or calcification)

US is reliable for identifying US is reliable for identifying tumor extension into renal tumor extension into renal vein or IVC (4-10% of cases)vein or IVC (4-10% of cases)

CT or MRI to delineate CT or MRI to delineate tumor extent; tumor tumor extent; tumor enhances to lesser extent enhances to lesser extent than surrounding than surrounding parenchymaparenchyma

CXR or CT to identify CXR or CT to identify pulmonary metastasespulmonary metastases

Wilms' in L kidney of 4 year old with hepatic mets

Tumor thrombus of portal v. in same patient

Wilms' tumor stagingWilms' tumor staging Stage I-confined to kidney without capsular or Stage I-confined to kidney without capsular or

IVC involvement; completely resectable with IVC involvement; completely resectable with capsule intactcapsule intact

Stage II-tumor extends beyond renal capsule Stage II-tumor extends beyond renal capsule or infiltrates vessels; resected tumor with or infiltrates vessels; resected tumor with confined local spillageconfined local spillage

Stage III-residual tumor confined to abdomen, Stage III-residual tumor confined to abdomen, including positive abdominal nodes, positive including positive abdominal nodes, positive surgical margins, diffuse peritoneal surgical margins, diffuse peritoneal contamination, or residual nonresected tumorcontamination, or residual nonresected tumor

Stage IV-hematogenous spread (lungs, nodes, Stage IV-hematogenous spread (lungs, nodes, liver)liver)

Stage V-bilateral diseaseStage V-bilateral disease

Don’t confuse Wilms' with Don’t confuse Wilms' with neuroblastoma!!neuroblastoma!!

Neuroblastoma-arises from anywhere along Neuroblastoma-arises from anywhere along sympathetic chain or adrenal medullasympathetic chain or adrenal medulla

Most common cancer of infancy and most Most common cancer of infancy and most common extracranial solid tumor of common extracranial solid tumor of childhood (90% dx <5 years; median age at childhood (90% dx <5 years; median age at dx 2 years)dx 2 years)

65% are intra-abdominal and they may 65% are intra-abdominal and they may invade renal tissueinvade renal tissue

Determining adrenal vs renal origin is Determining adrenal vs renal origin is difficult when there is no clear plane of difficult when there is no clear plane of separationseparation

Wilms' tumor vs Wilms' tumor vs NeuroblastomaNeuroblastoma

Wilms'Wilms' <10% are calcified; <10% are calcified;

more often a more often a curvilinear patterncurvilinear pattern

Occasional local para-Occasional local para-aortic adenopathy (less aortic adenopathy (less common than with common than with neuroblastoma)neuroblastoma)

IVC invasion has high IVC invasion has high positive predictive positive predictive valuevalue

Mets to lungs commonMets to lungs common

NeuroblastomaNeuroblastoma Often calcified; scattered Often calcified; scattered

pattern throughout masspattern throughout mass Large regional adenopathyLarge regional adenopathy High predictive value: High predictive value:

encasement of great vessels, encasement of great vessels, spinal canal invasion, spinal canal invasion, paravertebral massparavertebral mass

Moderate predictive value: Moderate predictive value: extension across midline, extension across midline, displacement of great displacement of great vesselsvessels

Mets to liver, bone commonMets to liver, bone common Elevated urine Elevated urine

catecholaminescatecholamines

Which is it?Which is it?

NeuroblastomaNeuroblastoma

This contrast-enhanced CT shows a large retroperitoneal mass adjacent to the left kidney with scattered hyperintense signal (calcification). The tumor encases the descending aorta.

Wilms' tumor and neuroblastoma account for the majority of abdominal masses.

The remainder of the slides will provide an overview of the less common renal neoplasms.

They will be addressed in two groups: benign and malignant neoplasms

Benign renal neoplasmsBenign renal neoplasms

NephroblastomatosNephroblastomatosisis

Mesoblastic Mesoblastic nephromanephroma

Multilocular cystic Multilocular cystic nephromanephroma

AngiomyolipomaAngiomyolipoma Ossifying renal Ossifying renal

tumor of infancytumor of infancy Hyperplastic perilobar nephroblastomatosis

NephroblastomatosisNephroblastomatosis Diffuse or multifocalDiffuse or multifocal kidney kidney

involvement of metanephric rests involvement of metanephric rests (embryonic renal tissue persisting (embryonic renal tissue persisting beyond 36 weeks)beyond 36 weeks)

Homogenous subcapsular Homogenous subcapsular hypodense regionshypodense regions on contrast on contrast CTCT

Increased risk for Wilms' tumor. Increased risk for Wilms' tumor. Present in:Present in: 41% of unilateral casesof WT41% of unilateral casesof WT 94% of metachronus WT94% of metachronus WT 99% of synchronus bilateral WT99% of synchronus bilateral WT

Similar associations as with Wilms' Similar associations as with Wilms' Tumor (e.g. Beckwith-Wiedemann)Tumor (e.g. Beckwith-Wiedemann)

Treatment is controversial as 99% Treatment is controversial as 99% resolve spontaneously ; serial resolve spontaneously ; serial screening recommended with screening recommended with assoc. syndromesassoc. syndromes

a) US of a) US of nephroblastomatosis (plus nephroblastomatosis (plus symbols)symbols)d) L kidney shows diffuse d) L kidney shows diffuse metanephric rests, while R metanephric rests, while R kidney shows 3 focal lesionskidney shows 3 focal lesions

Mesoblastic nephromaMesoblastic nephroma Most common renal neoplasm Most common renal neoplasm

in in 11stst three months three months Solid, uniform mass with Solid, uniform mass with

possible hypoechoic areas from possible hypoechoic areas from cystic change or necrosis, cystic change or necrosis, thereby making it difficult to thereby making it difficult to distinguish from Wilms' on US distinguish from Wilms' on US (or CT) (or CT)

Has ill-defined margins and no Has ill-defined margins and no capsule, thus needs wide capsule, thus needs wide surgical marginssurgical margins

Does not invade vascular Does not invade vascular pedicle or metastasizepedicle or metastasize

US-large, solid mass with low US-large, solid mass with low echogenicityechogenicity

CT-soft tissue attenuation; CT-soft tissue attenuation; enhances less than surrounding enhances less than surrounding parenchyma after contrastparenchyma after contrast

Prenatally diagnosed destructive renal mass; rim of capsule-like parenchyma; dx made after nephrectomy

CT w/ contrast in same patient; rim of renal parenchyma ventromedially; well-defined mass surrounded by fat

Multilocular cystic Multilocular cystic nephromanephroma

Tumor contains Tumor contains cystic cystic lesionslesions lined by epithelial lined by epithelial cells and fibrous septae cells and fibrous septae (septae are only solid (septae are only solid component of tumor)component of tumor)

Lining may contain Lining may contain blastema cells (cystic blastema cells (cystic partially differentiated partially differentiated nephroblastoma), which nephroblastoma), which may have malignant may have malignant potential. This can only be potential. This can only be discerned histologically.discerned histologically.

Bimodal distribution (Bimodal distribution (boys boys < 4< 4 yearsyears; women 40-60 ; women 40-60 years)years)

CT w/ contrast demonstrating cyst (arrow) within a cystic partially differentiated nephroblastoma

AngiomyolipomaAngiomyolipoma Rare in children, unless pt has Rare in children, unless pt has

tuberous sclerosis tuberous sclerosis 80% of TS patients have renal 80% of TS patients have renal

angiomyolipomas by age 10 angiomyolipomas by age 10 yearsyears

Hamartomatous lesions Hamartomatous lesions comprised of fat, smooth muscle, comprised of fat, smooth muscle, and blood vesselsand blood vessels

In TS, small, bilateral, multifocal In TS, small, bilateral, multifocal nodules, typically corticalnodules, typically cortical

Tendency towards Tendency towards aneurysm aneurysm formationformation with with spontaneous spontaneous bleedingbleeding in aneurysms >4 cm; in aneurysms >4 cm; treatment only indicated to treatment only indicated to manage hemorrhagemanage hemorrhage

US-highly echogenic, non-US-highly echogenic, non-shadowing foci correlating with shadowing foci correlating with fat contentfat content

CT w/contrast diagnostic if high CT w/contrast diagnostic if high fat content; otherwise, fat content; otherwise, unenhanced may be necessaryunenhanced may be necessary

Acute hemorrhage of angiomyolipoma on contrast CT

Selective digital subtraction angiography; increased irregular vascularity in area of angiomyolipoma (arrow); leaked contrast defines area of hemorrhage in pole

Ossifying renal tumor of Ossifying renal tumor of infancyinfancy

Rare tumor, Rare tumor, diagnosed in diagnosed in 11stst year year

CalcifiedCalcified renal renal hamartomashamartomas

Soft tissue mass Soft tissue mass arising from medulla, arising from medulla, occupies part of occupies part of collecting ductcollecting duct

Can cause sx of Can cause sx of obstruction, obstruction, hematuriahematuria

Malignant renal Malignant renal neoplasmsneoplasms

Wilms'Wilms' Clear cell sarcomaClear cell sarcoma Renal cell Renal cell

carcinomacarcinoma RhabdoidRhabdoid LymphomaLymphoma Renal medullary Renal medullary

carcinomacarcinoma RhabdomyosarcomRhabdomyosarcom

aa

Gross examination of Wilms' tumor exhibiting extension into the renal pelvis

Clear cell sarcomaClear cell sarcoma 4% of pediatric renal 4% of pediatric renal

neoplasmsneoplasms Age distribution similar to Age distribution similar to

Wilms' tumor (peak 3-5 Wilms' tumor (peak 3-5 years)years)

No features that are No features that are radiologically distinct radiologically distinct from WT (solid mass from WT (solid mass compressing, distorting compressing, distorting surrounding parenchyma surrounding parenchyma +/- cystic areas and +/- cystic areas and necrosisnecrosis

20% have bony 20% have bony metastases (bone scan metastases (bone scan recommended)recommended)

Mets also to lung, brain, Mets also to lung, brain, liverliver

CT in 13 month old with right renal mass showing extensive central necrosis (arrow) and hydronephrosis of adjacent calices (arrowheads)

Renal cell carcinomaRenal cell carcinoma Mean age in children is 9 Mean age in children is 9

yearsyears 1% of pediatric renal tumors1% of pediatric renal tumors WT is 30 times more WT is 30 times more

frequent in children overall; frequent in children overall; however, WT incidence is however, WT incidence is equal to RCC in 2equal to RCC in 2ndnd decade decade

More frequent with More frequent with von von Hippel-LindauHippel-Lindau

Generally Generally smaller than WTsmaller than WT at presentation; otherwise at presentation; otherwise radiographically indistinct radiographically indistinct from WTfrom WT

25% with calcifications 25% with calcifications (<10% in WT)(<10% in WT)

Lumbar aortic adenopathy Lumbar aortic adenopathy commoncommon

Coronal T1 MRI of renal cell carcinoma

Gadolinium enhanced MRI

RhabdoidRhabdoid 2-3% of pediatric renal 2-3% of pediatric renal

neoplasmsneoplasms Occur in 1Occur in 1stst year of life year of life High risk for synchronus High risk for synchronus

or metachronus posterior or metachronus posterior fossa tumors (esp. PNET)fossa tumors (esp. PNET)

Radiographically Radiographically indistinguishable from WTindistinguishable from WT

Crescent sign-Crescent sign-peripheral peripheral crescentic fluid in crescentic fluid in subcapsular or subcapsular or perinephric space on CT perinephric space on CT (not a high positive (not a high positive predictive value)predictive value)

Renal vein infiltration Renal vein infiltration commoncommon

Gross appearance of rhabdoid-round, lobulated mass

CT with contrast shows heterogeneously enhancing mass of L kidney

LymphomaLymphoma Non-Hodgkin’s lymphoma (esp. Non-Hodgkin’s lymphoma (esp.

Burkitt’s) commonly has renal Burkitt’s) commonly has renal involvement involvement 8-12% seen on CT8-12% seen on CT 64% on autopsy 64% on autopsy

Usually Usually bilateralbilateral dz--spread dz--spread hematogenously or by direct hematogenously or by direct extensionextension

Common appearances:Common appearances: Multiple parenchymal Multiple parenchymal

masses/nodules that distort the renal masses/nodules that distort the renal contour and displace the collecting contour and displace the collecting systemsystem

Invasion from retroperitoneal mass or Invasion from retroperitoneal mass or adjacent lymph nodesadjacent lymph nodes

CT-homogenous, hypodense on both CT-homogenous, hypodense on both enhanced and unehancedenhanced and unehanced

Multifocal, nodular dz-may appear Multifocal, nodular dz-may appear like multiple renal cystslike multiple renal cysts

Diffuse dz-general renal enlargementDiffuse dz-general renal enlargement Associated Associated splenomegaly, splenomegaly,

abdominal adenopathyabdominal adenopathy, elevated , elevated LDHLDH

Gadolinium enhanced MRI of patient shows lymphomatous infiltration of the lower pole in both the coronal (b) and transverse (c) image; coronal also shows small focus in upper pole

Renal medullary Renal medullary carcinomacarcinoma

Aggressive tumorAggressive tumor Quickly fills renal pelvisQuickly fills renal pelvis Invades vessels, lymphaticsInvades vessels, lymphatics Unfavorable prognosisUnfavorable prognosis

Most common in Most common in adolescents, young adolescents, young adults withadults with sickle cell sickle cell traittrait (SA, SC); no increased (SA, SC); no increased prevalence in SS diseaseprevalence in SS disease

Centrally located, Centrally located, infiltrative lesion invading infiltrative lesion invading renal sinusrenal sinus Peripheal caliectasisPeripheal caliectasis Reniform enlargementReniform enlargement

Adjacent adenopathy Adjacent adenopathy commoncommon

US demonstrating lack of corticomedullary differentiation; hydronephrosis in calices

CT with contrast shows heterogeneous, infiltrating mass (curved areas); hypodense areas reflecting hydronephrosis; extenseive paravertebral and para-aortic adenopathy (straight arrows)

RhabdomyosarcomaRhabdomyosarcoma Most common pediatric Most common pediatric

malignancy of the malignancy of the pelvispelvis GU tract is the 2GU tract is the 2ndnd most most

common site after head & common site after head & neckneck

MRI preferred over CTMRI preferred over CT MRI, CT both show MRI, CT both show

excellent contrast excellent contrast enhancementenhancement

Solid mass of muscle Solid mass of muscle density with areas of density with areas of necrosisnecrosis

Botyroid subtype accounts Botyroid subtype accounts for 5% (grape-like, polypoid for 5% (grape-like, polypoid mass most common in mass most common in vagina)vagina)

Pelvic rhabdomyosarcoma

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Images obtained from above sources as well as Google Images