Wilms Tumor

Michael P. D'Alessandro, M.D.
Peer Review Status: Internally Peer Reviewed

Etiology/Pathophysiology:
Originates in the kidney, displaces and distorts the pelvicalyceal system, and replaces most of the involved kidney, and has central hemorrhage and necrosis. Can invade the renal vein and IVC (12-20% ), and can spread via blood, lymphatics, and direct extension. The most common site of metastases is the lung, liver metastases are seen in 8-10% , and bone metastases are rare. Five to ten percent are bilateral and this can be due to a malignant progression of nephroblastomatosis, multicentric tumor, or metastases. Nephroblastomatosis has no capsule, hemorrhage, or necrosis unlike Wilms which has all three.

Pathology:
Fairly well differentiated renal tissue with embryonic glomeruli and tubules.

Imaging Findings:
Abdominal film shows a non calcified abdominal mass.

Ultrasound shows a solid mass arising from the kidney with a heterogenous echotexture due to hemorrhage and necrosis that deforms the renal collecting system.

Imaging work up should include an ultrasound for initial imaging of the abdominal mass to include a color Doppler ultrasound to assess for renal vein invasion and thrombosis, a MR or CT to assess for disease extent, and a bone scan to look for bone metastases.

DDX:
Renal Masses

• Multilocular cystic nephroma
• Mesoblastic nephroma
• Nephroblastomatosis
• Renal cell carcinoma
• Hydronephrosis
• Multicystic dysplastic kidney
• Cystic renal diseases

References:

• Correlapedia

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