Intraglomerular microlesions in renal angiomyolipoma

A unique case of bilateral multiple intrarenal angiomyolipomas in a 81-year -old woman with tuberous sclerosis is reported. The microscopic examination showed peculiar intraglomerular microlesions, epithelioid areas, microscop ic foci of renal cell carcinoma and renal cysts, and the classical features of angiomyolipoma lesion. HMB-45 positivity was detected within some nodul es and epithelioid areas. Intraglomerular microlesions were composed of adi pose and smooth-muscle cells within the glomerular capillary tuft. These le sions, which were continuous with the capillary tuft, did not show any atta chment to the Bowman's capsule. These findings suggest that these are not a consequence of an infiltration from the outside but were originated from i nside the glomerulus. The simultaneous presence of multiple angiomyolipoma nodules either inside or outside the glomeruli, multifocality and bilateral ity of these lesions, together with the HMB-45 positivity and the finding o f scattered epithelioid areas supports the theory that there is a progenito r cell giving origin to all these lesions, the cell which has been named as perivascular epithelioid fell by most authors. HUM PATHOL 31:1325-1328, Co pyright (C) 2000 by W.B. Saunders Company.