Renal oncocytoma

A renal oncocytoma is a tumour of the kidney made up of oncocytes, epithelial cells with an excess amount of mitochondria.

[1][2] Renal oncocytomas are often asymptomatic and are frequently discovered by chance on a CT or ultrasound of the abdomen.

Possible signs and symptoms of a renal oncocytoma include blood in the urine, flank pain, and an abdominal mass.

Renal oncocytoma is thought to arise from the intercalated cells of collecting ducts of the kidney.

In gross appearance, the tumors are tan or mahogany brown, well circumscribed and contain a central scar.

Renal oncocytoma of the right kidney at CT.
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.
Histopathologic types of kidney tumor, with relative incidences and prognoses. Oncocytoma is seen at right in the pie chart.