Intracranial hemangiopericytomas. Histological and immunohistochemical study

The authors report on 8 cases of intracranial supratentorial tumors which clinically corresponded to meningeal neoplasms. Only one patient revealed the recurrence. The age of patients was 39-74, prevailed women (5). Histological features of tumors, except some variations in two cases agreed with common morphologic pattern of hemangiopericytomas. Immunohistochemical study with following antibodies was performed: vimentin, epithelial membrane antigen, cytokeratin, S-100 protein, fibronectin, desmin, collagen IV, factor RAg, and glial fibrillary acidic protein. Two atypical cases which presented scarce pseudocalcifications and tendency to concentric cellular structures did not differ from other hemangiopericytomas by their intrinsic immunohistochemical properties such as negative reaction to epithelial membrane antigen and cytokeratin. Atypical positive immunostaining with S-100 protein and with glial fibrillary acidic protein was found solely in the group or perivascular cells in one of those atypical cases reflecting probably local astrocytes embedded in tumor tissue. Immunohistochemical investigations did not present univocal data to explain controversial origin of hemangiopericytomas either from meningeal cup cells or from vascular pericytes.