Unilateral facial angiofibromas--a segmental form of tuberous sclerosis.

Multiple facial angiofibromas are thought to be a pathognomonic and common, feature of tuberous sclerosis. In contrast, it is rare to see multiple angiofibromas limited to one side of the face. We have studied a patient with multiple angiofibromas of one cheek, in order to search for other manifestations of tuberous sclerosis and to determine the histochemical identity of the angiofibromas. No evidence of other pathology known to be associated with the tuberous sclerosis complex was uncovered. Histopathology of the unilateral lesions revealed focal fibroplasia and positive cellular staining for factor XIIIa and vimentin, similar to that described for bilateral angiofibromas. We suggested that the segmental expression of tuberous sclerosis, in the form of unilateral facial angiofibromas, may result from a postzygotic mutation.