| Renal oncocytoma | |
|---|---|
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| Micrograph of arenal oncocytoma. |
Arenaloncocytoma is a benignneoplasm of thekidney made up ofoncocytes,epithelial cells with an excess amount ofmitochondria.[1][2]
Renal oncocytomas are often asymptomatic and are frequently discovered by chance on aCT orultrasound of the abdomen. Possible signs and symptoms of a renal oncocytoma includeblood in the urine, flank pain, and anabdominal mass.
Renal oncocytoma is thought to arise from theintercalated cells ofcollecting ducts of the kidney. It represent 5% to 15% of surgically resectedrenalneoplasms. Ultrastructurally, the eosinophilic cells have numerousmitochondria.
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An oncocytoma is anepithelial tumor composed of oncocytes, largeeosinophilic cells having small, round, benign-appearingnuclei with largenucleoli and excessive amounts ofmitochondria.
Ingross appearance, the tumors are tan or mahogany brown, well circumscribed and contain a central scar. They may achieve a large size (up to 12 cm in diameter).
The maindifferential diagnosis of renal oncocytoma ischromophoberenal cell carcinoma oncocytic variant, which like the renal oncocytoma has eosinophilic cytoplasm, but has perinuclear clearing and some degree ofnuclear atypia.
Renal oncocytoma is consideredbenign, cured bynephrectomy (partial if possible based upon size). There are some familial cases in which these tumors are multicentric rather than solitary.[4] However, they may be resected to exclude a malignant tumor, e.g.renal cell carcinoma.
The overallfive-year survival rate has been estimated to be 63%, with 100% disease-specific survival.[5]
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