Cerebellar hemangioblastoma: Histogenesis of stroma cells

Light and electron microscopic features of a cerebellar hemangioblastoma were evaluated with special emphasis on the matter of the origin of interstitial (stroma) cells. Many of the capillary components were of embryonal type, and the stroma cells shared several morphological features with them. It was concluded that the stroma cells originate from vasoformative elements (endothelium and pericytes) and that the endothelial cells are active components of the neoplasm. No convincing morphological counterpart for the erythropoietic activity of this neoplasm was uncovered. Structures identical to ciliary rootlets were identified in many endothelial cells.