Rhabdoid Glioblastoma: an Aggressive Variety of Astrocytic Tumor

Rhabdoid glioblastoma (RGBM) is rare, but the most malignant among astrocytic tumors. Accumulating evidence indicates its highly aggressive nature and distinct histopathological features. Here, we report a new case of RGBM and review previously reported cases of astrocytic tumors with rhabdoid components. We describe a 58-year-old man who presented with aphasia and right-sided weakness. Magnetic resonance imaging revealed a well-delineated intramedullary tumor in the left cerebral hemisphere. Partial resection of the tumor was performed. The tumor was histologically found to contain two distinct areas: a typical glioblastoma, and a rhabdoid component. Immunohistochemical analyses revealed expression of glial fibrillary acidic protein (GFAP) and focal loss of the INI1 protein in rhabdoid cells, although fluorescence in situ hybridization analysis showed no loss of the INI1 gene. Despite subsequent radiochemotherapy for the glioblastoma, the patient died 4.3 months after surgery. Our literature review illustrates the aggressive clinical course and histopathological features of these tumors with GFAP and INI1 expression. INI1 protein dysfunction may be a possible cause of the rhabdoid phenotype. Gross total resection of the tumor and intensive radiochemotherapy may lead to better survival outcomes.