In meningiomas, transformed meningeal cells can share morphological aspects (in hemangiopericytic meningioma) and antigenic properties (i.e.: HLA-DR antigens expression) with elements of the monocyte/macrophage lineage. In this report, we describe a case of a highly vascular meningioma where numerous tumor cells, studied with immunohistochemical methods, present phenotypic properties of macrophages. Moreover, the cerebrospinal fluid (CF) analysis disclosed, using a biological assay, a high level of a growth factor for monocytic elements, the Macrophages Colony Stimulating Factor (M-CSF). Our findings may confirm that transitional aspects between different mesenchymal cells could be present in meningiomas.
