Renal oncocytoma

Renal oncocytomas are often asymptomatic and are frequently discovered by chance on a

mass.

Pathophysiology

Renal oncocytoma is thought to arise from the

mitochondria

.

Histologic appearance

This section needs expansion. You can help by adding to it. (January 2011)

An oncocytoma is an

mitochondria

.

Diagnosis

Gross

appearance of a renal oncocytoma (left of image) and a slice of a normal kidney (right of image). Note the rounded contour, the mahogany colour and the central scar.

In

gross

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 main differential diagnosis of renal oncocytoma is chromophobe renal cell carcinoma oncocytic variant, which like the renal oncocytoma has eosinophilic cytoplasm, but has perinuclear clearing and, typically, some degree of nuclear atypia.

Immunohistochemical profile

• Cytokeratin AE1/AE3 +
• Vimentin -
• EMA
  +
• CD10
  +/-
• CK7
  +/- parcellaire
• CK20
  -
• CK19
  -
• Racemase
  ) -
• S100 +
• c-kit (
  CD117
  ) +
• Cadherin-E +
• TFE3 -
• CAM5.2
  +

^[3]

Treatment

Renal oncocytoma is considered benign, cured by nephrectomy. 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.

Prognosis

The overall five-year survival rate has been estimated to be 63%, with 100% disease-specific survival.^[5]

Additional images

• 
  Micrograph of a renal oncocytoma. H&E stain.
• 
  Micrograph of a renal oncocytoma. H&E stain.
• 
  Micrograph of a renal oncocytoma. H&E stain.
• 
  Micrograph of a renal oncocytoma. H&E stain.
• 
  Micrograph of a renal oncocytoma. H&E stain.
• 
  Micrograph of chromophobe RCC oncocytic variant, the main differential diagnosis of renal oncocytoma.

See also

• Kidney
• Renal cell carcinoma

References