Malignant gliomas with heavily lipidized (foamy) tumor cells: a report of three cases with immunoperoxidase study.

Three cases of heavily lipidized malignant glioma are reported. Large amounts of intracellular lipid gave the tumor cells a vacuolated, foamy appearance that generally obscured their glial nature. The latter was, however, confirmed by the demonstration of glial fibrillary acidic protein (GFAP) by immunoperoxidase. These tumors, which were situated deeply in the brain and contained areas of necrosis, must be distinguished from the relatively benign pleomorphic meningocerebral xanthoastrocytomas, which are characteristically superficial in their location and lack necrotic foci. The malignant nature of the presently described tumors is shown by the death of all three patients within one year of surgery. Thus, in the biologic sense these tumors represent glioblastomas; however, their morphologic peculiarities in the form of massive lipidization of tumor cells, apparently not caused by necrobiosis, set them aside as a histologic subgroup.