Renal angiomyolipomas--a study of 18 cases.

Angiomyolipoma is a distinctive neoplasm composed of an intimate admixture of three components, viz. mature adipocytes, smooth muscle cells and blood vessels. This study was undertaken to better define the various morphological patterns of angiomyolipoma and their immunohistochemical profile. The paraffin blocks and slides of 18 cases of renal angiomyolipoma, accessioned over a period of 8 years from Tata Memorial Hospital, were reviewed. There were 2 men and 16 women in the age range of 17 to 68 years. Pre-operative fine needle aspiration cytology (FNAC) was performed in 6 cases, of which 5 were erroneously diagnosed as renal cell carcinomal sarcoma. Histologically, 14 cases revealed conventional histology. The remaining 4 cases were particularly misleading posing diagnostic problems due to variant patterns (leiomyomatous variant-3 cases and epithelioid variant- 1 case). Apart from the usual histology, necrosis, giant cells, and varying degrees of nuclear pleomorphism were present in three of the cases. Immunohistochemistry performed in 16 cases revealed immunoreactivity for HMB45 in all the 16 tumors (100%), estrogen receptor (ER) and progesterone receptor ((PR) in 2 cases (12.5%) and 6 cases (37.5%) respectively.