[Intraventricular glial tumor. in the evolution of Bourneville tuberous sclerosis: ultrastructural study].

Ultrastructural study of an intraventricular tumour in a child with Bourneville tuberose sclerosis showed the presence of marked glial astrocytic proliferation. All the tumour cells were undoubtedly of astrocytic type, as shown by the presence of gliofilaments and beta-type glycogenic particles. They were also characterized by an abundant ergastoplasm of an original type (lamellar stacking of the saccules), a well developed Golgi apparatus, a multitude of mitochondria and numerous dense lysosomic bodies, indicative of metabolic hyperactivity. On the basis of these morphological date, the tumour may be defined as an astrocytoma, the blastic tendency of which cannot be affirmed, other than on the basis of the presence of mitotic figures.