Angiomyolipoma (AML) is a benign renal neoplasm composed of fat, vascular, and smooth muscle elements. It has an incidence of about 0.3-3%. Two types are described: isolated AML and AML associated with tuberous sclerosis.

Interestingly, 80% of the cases involve the right kidney.

Most small lesions are asymptomatic and incidental findings on images. As many as 40% are symptomatic; these can cause a palpable abdominal mass, hematuria, or flank pain. The solitary sporadic tumors may cause acute abdomen and shock as a result of spontaneous hemorrhage in the tumor. The demonstration of fatty attenuation in renal tumor is virtually diagnostic of AML.