HMB-45 REACTIVITY IN RENAL ANGIOMYOLIPOMA AND LYMPHANGIOLEIOMYOMATOSIS

Recent reports have elucidated the variety of tissue types that can re act with HMB-45. Consistent positivity has been demonstrated in angiom yolipomas, but only in the smooth-muscle cells. In this report, we exa mine five renal angiomyolipomas and 20 mesenchymal lesions with simila r morphological features and with a possibly similar histogenesis. The se include one retroperitoneal lymphangioleiomyomatosis, five epitheli oid leiomyomas, nine leiomyosarcomas with epithelioid features, and fi ve alveolar soft part sarcomas. HMB-45 demonstrated a strong diffuse c ytoplasmic positive reaction with the smooth-muscle component in all c ases of renal angiomyolipoma and in the one case of lymphangioleiomyom atosis. All alveolar soft part sarcomas, leiomyomas, and leiomyosarcom as were uniformly negatively stained by this antibody. We discuss the widening spectrum of lesions that are reactive with HMB-45 and the rel ationship of angiomyolipoma and lymphangioleiomyomatosis.