A benign (noncancer) tumor of fat and muscle tissue that usually is found in the kidney. Angiomyolipomas rarely cause symptoms, but may bleed or grow large enough to be painful or cause kidney failure. They are common in patients with tuberous sclerosis (a genetic disorder in which benign tumors grow in the kidneys, brain, eyes, heart, lungs, and skin, causing seizures, mental problems, and skin lesions).

A benign tumor containing vascular, adipose, and muscle elements. It occurs most often in the kidney with smooth muscle elements (angiolipoleiomyoma) in association with tuberous sclerosis. (Dorland, 27th ed)

A neoplasm with perivascular epithelioid cell differentiation often associated with tuberous sclerosis. It is characterized by a mixture of epithelioid cells, smooth muscle, vessels, and mature adipose tissue. The kidney is the most common site of involvement. Other sites of involvement include the liver, lung, lymph nodes, and retroperitoneum. The vast majority of cases follow a benign clinical course. However, cases of metastatic angiomyolipomas with sarcomatoid features have been described.