Ultrastructural study of subependymal giant cell astrocytoma: unusual paracrystalloid inclusions in tumour cells.

Subependymal giant cell astrocytoma (SEGA) is a tumour with a broad range of morphological, immunohistochemical and ultrastructural neoplastic cellular features. We report here the presence of this tumor in two 7-year-old-boys presented with a lateral intraventricular mass. Further clinical investigation confirmed the diagnosis of tuberous sclerosis. Ultrastructural and immunohistochemical investigation revealed that glial differentiation was more pronounced in these cases. Interestingly, tumour cells containing unusual paracrystalline inclusions, infrequently described in SEGA, were identified ultrastructurally. These inclusions are probably not related to other cellular organelles.