Case of radiologically multicentric but genetically identical multiple glioblastomas

Surgery was performed in a 65-year-old male patient with malignant gliomas at two locations in the left and right cerebral hemispheres that showed no apparent continuity in imaging studies. Slight differences in histopathological appearance were seen between the tumors, and multicentric malignant glioma was diagnosed. Detailed genetic examination showed both the left- and right-side tumors to be of the IDH-1 wild type with a p53 mutation at the same locus. Whole genome analysis by comparative genomic hybridization revealed many of the same mutations to be present in both tumors. The O(6)-methylguanine-methyltransferase promoter in both cases was unmethylated, and the genetic profiles of both showed them to be homologous tumors. They were therefore inferred to be multiple gliomas from the same clone. There have been occasional reports of multicentric gliomas classified by diagnostic imaging. This report discusses the need to examine tumor origin by genomic profiling.