Intracranial malignant fibrous histiocytoma: characterization of GFAP-positive cells in the tumor
Hirato, J.; Nakazato, Y.; Sasaki, A.; Yokota, M.; Nojiri, K.; Toyoda, O.; Nakajima, H.
Clinical Neuropathology 13(6): 315-322
1994
ISSN/ISBN: 0722-5091 PMID: 7851046 Document Number: 434194
A case of malignant fibrous histiocytoma (MFH) arising in the cerebellopontine angle of a 57-year-old woman was reported. The immunohistochemical and electron microscopic findings indicated distinct fibrohistiocytic nature and myofibroblastic differentiation of this peculiar tumor. Immunohistochemistry disclosed that the tumor cells expressed monocyte/macrophage markers including CD-68, MAC 387, and alpha-1-antichymotrypsin. In addition, the neoplasm contained scattered glial fibrillary acidic protein (GFAP)-positive cells which made small nests in some areas. These GFAP-positive cells had bundles of densely packed intermediate filaments and scanty organellae in the cytoplasm, as demonstrated by an immunostained-semithin and serial-ultrathin section method. By immunostaining of MIB-1 and GFAP, and silver nucleolar organizer region (AgNOR) impregnation on serial sections, the GFAP-positive cells were not labeled by MEB-1 and their AgNOR counts averaged 1.13/nucleus. Thus, these GFAP-positive cells seem to have lower proliferating activity than neoplastic astrocytes. It is concluded that they may be nonneoplastic astrocytic cells involved by MFH.