[Renal angioleiomyoma with a myogenic and melanocytic immunophenotype, as a variant of angiomyolipoma].

We present a case of a 67 year old male with a cortical nodular tumour of the left kidney. During a year's follow-up with ultrasound and MRI, the tumour was seen to increase in size by 16-20 mm. The nodule was surgically removed. Microscopically it was well defined and unencapsulated, with a proliferation of typical fusiform cells of smooth muscle cell appearance, clumped around well vascularized areas. Immunohistochemically, the neoplasm was positive for muscle markers (smooth muscle actin, desmin and caldesmon) and melanocyte markers (HMB-45 and Melan A). Our case would appear to be a renal neoplasm with an angioleiomyomatous pattern, but with immunohistochemical characteristics of angiomyolipoma (PEComa), however, without either a lipomatous or lipid cell component. We found no previous reports of this type of tumour in the literature.