Abstract
The histogenesis of intracranial hemangiopericytoma has been the subject of considerable debate. Using tumor tissue taken at surgery from a 35-year-old male patient, we studied the fine structure of hemangiopericytoma. Both in vivo and in vitro, electron microscopy has shown characteristic features of the pericytes of Zimmermann, which are quite different from those of meningioma. Among the most outstanding and consistent features of the hemangiopericytoma that we studied were cytoplasmic triangular or rod-shaped dense bodies, an intercellular basement membrane, and electron-dense materials. These findings suggest leiomyoblastic differentiation of hemangiopericytoma cells and support the proposition that pericytes are precursors of smooth muscle cells.
