Anaplastic oligodendroglioma presenting with apoplectic intratumoral hemorrhage.

A 31-year-old woman presented with a headache and nausea. At presentation, her blood pressure was 114/71 mm Hg with left hemiparesis. Computed tomography revealed a large hyperdense mass in the right temporal lobe accompanied by intralesional calcifications and ventricular perforation. Spot signs were not identified, and cerebral angiography did not reveal any abnormal vasculature. The patient underwent emergency craniotomy assuming an intracerebral hemorrhage. Intraoperatively, grayish tumor tissue was found to intermingle with the clots. Microscopic findings of the tumor revealed neoplastic cells possessing perinuclear halo and cell atypia, and diffusely stained with glial fibrillary acidic protein, which were consistent with anaplastic oligodendrogliomas. However, genomic analyses of the tumor showed non-mutant isocitrate dehydrogenase 1 and telomerase reverse transcriptase, in addition to wild-type O6-methylguanine DNA-methyltransferase. These are equivalent to glioblastoma multiforme. Based on the results, we assumed that anaplastic oligodendrogliomas may develop apoplectic intratumoral hemorrhages that mimic intracerebral hemorrhage. Genomic exploration is recommended for such tumors, coupled with careful follow-up, owing to its potentially aggressive nature.