LIPIDIZED MENINGOTHELIAL TUMOR-CELLS IN XANTHOMATOUS MENINGIOMA EXPRESS MACROPHAGE ANTIGEN

A case of ''xanthomatous'' meningioma was examined by light and electron microscopy as well as immunohistology. Lipid-laden ''xanthomatous'' cells were shown to be meningothelial by all ultrastructural criteria. All tumor cells (lipidized and non-lipidized) expressed vimentin in their cytoplasm, but only the lipidized cells showed the presence of the macrophage marker HAM-56. This finding suggests that, as in some other areas of general pathology, immunological markers may serve as indicators of a specific activity (in this case phagocytosis), rather than merely histogenesis.