Glioblastoma multiforme with epithelial appearance: a case report.

A case of glioblastoma multiforme with epithelial appearance, which was difficult to diagnose at first operation, is described. Microscopy revealed small, darkly staining anaplastic cells which were densely packed. In some areas, these cells were arranged in a tubular, gland-like pattern mimicking a poorly differentiated epithelial neoplasm. Immunostaining of glial fibrirally acidic protein (GFAP) was negative in the densely compact anaplastic areas and within the epithelial patterns, except for a small number of cells in one area. Further pathological study at the second and third operations indicated that the tumor consisted of neoplastic astrocytes and had characteristic features of glioblastoma multiforme, including necrosis, pseudopalisading, and endothelial proliferation. Many of the tumor cells were GFAP-positive. This rare case of glioblastoma multiforme was compared with cases reported in the literature.