Angiomyolipomas and polycystic renal disease in tuberous sclerosis. Ultrastructural observations.

We report the ultrastructure of bilateral renal angiomyolipomas in a case of tuberous sclerosis. The patient also had adult-type polycystic renal disease (Potter type 3) with systemic hypertension. Smooth muscle differentiation was supported by immunofluorescence localization of contractile protein using both smooth muscle and platelet-specific antibodies against myosin. There were cells with ultrastructural features intermediate between mature smooth muscle and fat suggesting origin from progenitor pericytic cells closely related to vascular endothelium. There was also evidence of secretory or synthetic capacity by some mesenchymal cells raising the possibility that hypertension in part may have been hormonally mediated by tumor. A unifying theory of histogenesis is proposed with special reference to the study of Wassermann regarding embryonal lipogenesis.