Histopathologic investigation of a case of meningioangiomatosis not associated with von Recklinghausen's disease.

A case of meningioangiomatosis not associated with von Recklinghausen's disease is reported. Microscopically, irregularly branched blood vessels extending into the gray matter from the meningeal surface are surrounded by a concentric arrangement of proliferating spindle-formed cells. Ultrastructurally these proliferating cells are composed of elongated heterochromatin-rich nuclei and slender cytoplasm-containing microfilaments, occasionally associated with desmosomal junctions and basal laminalike structures. Judging from these findings, together with a negative immune reaction for S-100 protein, the histogenesis of these proliferating cells is most probably meningothelial in origin.