Angiomyolipoma of the bladder.

Angiomyolipoma of the bladder is an extremely rare neoplasm. We report a case of a 55-year-old woman with an angiomyolipoma of the bladder visualized on pelvic sonogram as a 5 mm polyp in the floor of the bladder. The lesional tissue consisted of spindle cells, epithelioid cells, and adipocytes, with occasional thick-walled blood vessels. Immunohistochemical studies showed the spindle and epithelioid cells to be focally positive for HMB-45 and diffusely positive for actin and muscle cell antigen (HHF-35), which confirmed the diagnosis of angiomyolipoma. A review of the recent literature on the pathogenesis of angiomyolipoma follows. Copyright 2002, Elsevier Science (USA). All rights reserved.