OBJECTIVETo discuss the clinicopathologic features of rhabdoid glioblastoma of the brain and its differential diagnoses.

METHODSA 10-year-old and a 45-year-old female both presented with gradually worsening headache, limbs twitch and blurred vision. MRI scan revealed a contrast enhancing tumor in the right temporal lobe and left cerebellum respectively. Both patients underwent tumor resection, followed by postoperative radiotherapy and chemotherapy.

RESULTSMicroscopic examination of both tumors showed rhabdoid tumor cells with an eccentric nuclei and eosinophilic cytoplasms. Both tumors had areas of classic glioblastoma with microvascular proliferation and necrosis. Immunohistochemical staining showed the rhabdoid tumor cells were positive for vimentin diffusely and GFAP, EMA, CK focally. Integrase interactor (INI-1) was expressed in most tumor cells, but IDH1 R132H was not detected in both tumors. Fluorescence in situ hybridization revealed 1p/19q co-deletion in one case. One patient was alive without tumor recurrence after 16 months follow-up, the other patient died of intraspinal tumor dissemination 9 months after surgery.

CONCLUSIONSRhabdoid glioblastoma is a rare glial cell tumor with specific rhabdoid tumor cells, a highly aggressive clinical course and poor prognosis. Combining histological features, a panel of selected immunostains including vimentin, GFAP, CK, EMA, SMA and INI-1 is helpful in making an accurate diagnosis for those diagnostically challenging cases with rhabdoid features in central nervous system.