Malignant epithelioid angiomyolipoma ('Sarcoma ex angiomyolipoma') of the kidney - A case report and review of the literature

Malignant epithelioid angiomyolipoma is a recently described rare tumor of the kidney. Its existence has been questioned, however, on the basis of inc omplete evidence of malignant behavior, the absence of an associated classi c angiomyolipoma component, or the absence of immunoreactivity for HMB-45 i n some cases. We describe a case that was HMB-45-positive and arose in asso ciation with a classic angiomyolipoma. The patient was treated with a parti al nephrectomy. Three years later, she developed rapidly enlarging liver no dules. A fine-needle aspiration of the liver confirmed the presence of pleo morphic epithelioid cells morphologically and immunohistochemically identic al to those comprising the primary renal tumor. After two cycles of treatme nt with doxorubicin, there was a 50% reduction in the size of the tumors wi th marked improvement in performance status. We believe this case confirms the existence of a malignant epithelioid angiomyolipoma.