Renal angiomyolipomas: could the histology serve as a marker for tuberous sclerosis?

The histological features of 43 renal angiomyolipomas were studied in an attempt to evaluate whether the isolated forms and those that present as part of the tuberous sclerosis complex can be distinguished. In two patients the mass was classified as an angioleiomyoma, because no adipose tissue was present. All renal angiomyolipomas showed the same basic histological picture. The combined forms, however, showed additional features such as extension into pre-existent renal parenchyma, scattered foci of hamartomatous lesions, calcified spicules and tubular inclusions. The findings suggest that these features, in an otherwise classical angiomyolipoma, should alert the pathologist to the possibility of tuberous sclerosis.