Renal angiomyolipoma is a benign neoplasm of the kidney, and is the most common renal tumor associated with hemorrhage. On CT, angiomyolipomas appear to have well defined margins, with a variable proportion of fat and soft tissue. Risk of bleeding increases with the size of the angiomyolipoma. There is a 13% risk of bleeding if the lesion is < 4 cm and a 51% risk if > 4 cm.

Case courtesy Dr.ssa Luisa Coletta

Radiographer: TSRM Fabio Imola