Image Description
Angiomyolipoma (AML) of the kidney is a member of a group of tumors collectively called PEComas (the cell of origin being Perivascular Epithelioid Cell). Other members of the PEComa family include clear cell "sugar tumor" of the lung and extrapulmonary sites, lymphangioleiomyomatosis, clear cell myelomonocytic tumor of the falciform ligament/ligamentum teres, and clear cell tumors in other locations. In its typical form, AML is composed of mature adipose tissue, blood vessels, and smooth muscle cells. The gross appearance depends upon the relative amounts of its various components. Some tumors have abundant fat and resemble lipomas. Other may have areas of hemorrhage and mimic renal cell carcinomas. Capsular invasion and extension into perirenal soft tissues may be present (as seen in this case).