Diagnostic and therapeutic problems in multicentric renal angiomyolipoma.

Multicentric renal angiomyolipoma is a rare form of benign tumor. However, its effective incidence as evaluated in autopsy studies may be as high as 8%. There are 2 main types of renal angiomyolipoma, that is isolated forms and those associated with other diseases, such as phakomatosis, polycystic kidneys and fibromuscular dysplasia. The tumor may also display malignant behavior with local invasiveness and regional lymph node involvement. However, the clinical course is benign and multicentricity is important for prognosis. Histopathological diagnosis often is difficult. Immunohistochemical analysis of surgical specimens using a panel of monoclonal antibodies, including HMB-45 and actin, enabled us to make a definitive diagnosis in 3 cases of multicentric renal angiomyolipoma.