TUBEROUS SCLEROSIS IN A 20-WEEK GESTATION FETUS - IMMUNOHISTOCHEMICALSTUDY

We report an autopsy case of tuberous sclerosis complex (TSC) in a 20- week gestational age female fetus, The brain showed lesions suggestive of early cortical tubers and subependymal hamartomatous nodules, The large tells within these nodular clusters were variably immunoreactive for glial fibrillary acidic protein (GFAP) and vimentin and negative for synaptophysin and neurofilament, Subependymal radial glia expresse d both vimentin and GFAP, but subpial radial glia either did not expre ss these markers (in contrast to an age-matched control) or were absen t. Tuberin expression was noted in heterotopic neurons in the white ma tter and brain cells consistent with Cajal Retzius cells in the neocor tical molecular layer, very weakly in superficial cortical neurons, ne urons in the basal ganglia, Purkinje cells and external granular cells of cerebellum, cranial nerve nuclei neurons, occasional germinal matr ix cells, ependymal cells, choroid plexus epithelium, and pituitary gl and neuroendocrine cells; it was nor seen within the cells of subepend ymal nodules. The pattern of tuberin immunoreactivity tvas similar to that which we have observed in older TSC patients. Proliferating cell labeling indexes were comparable in the germinal matrix of the TSC pat ient and an age-matched control. Abnormal subpial radial glia may be r esponsible for some of the neuronal migration abnormalities that appea r to result in neocortical tubers.