Background: Glioblastoma with oligodendroglioma component (GBMO) is a recently classified subtype of glioblastoma, which carries different clinical and prognostic outcomes, being frequently misdiagnosed. Both glioblastoma and GBMO are mainly seen in older ages, such as the 5th and 6th decades of life, being an extremely rare occurrence in children or adolescents and more frequent in male patients.
Case report:A 15-year-old female patient, presented with history of daily headache, not relieved by painkillers, vomiting, blurred vision and strabismus. Magnetic resonance imaging of the brain revealed expansive tumour on left temporo-occipital lobe. Patient was submitted to intracranial exeresis, along with histopathological examination: glial neoplasm with areas of pleomorphism, hyperchromatism, anaplasia, foci of oligodendroglial component, perinuclear halo and ramified capillaries, resembling oligodendroglioma, necrosis and intense mitotic activity. The immunohistochemical analysis revealed positive Glial Fibrillary Acidic Protein (GFAP), synaptophysin, Ki-67 (MindBomb E3 ubiquitin protein ligase 1 -MIB-1) and hyperexpression of Epidermal Growth Factor Receptor (EGFR), indicating GBMO. Subsequently, Fluorescence in situ Hybridization (FISH) showed positive for 19q deletion, negative for 1p deletion and also positive for Isocitrate Dehydrogenase 1 (IDH 1) mutation, suggesting an oligodendroglioma component. Tumour resection was total and symptoms disappeared. Afterwards, she started adjuvant oral chemotherapy with temozolomide. Treatment was completed after 12 cycles adjuvant temozolomide, with no greater symptoms or complications and complete remission. Furthermore, according to the most recent WHO classification, in 2016, a new addition was made to this diagnosis: the evidence of isocitrate dehydrogenase (IDH) mutation, which is present on about 10% of gliobastomas [2]. This genetic marker has been shown as an important predictor of prognostic and longer survival rate [3,4,5].Moreover, the overall median survival of GBMO and GBM are still controversial, since it has shown a longer survival [4] in GBMO while others did not identify differences whatsoever [5].Regarding age, although GBMO has been said to have a younger onset than GBM, both are mainly seen on older ages, such as the 5th and 6th decades of life, being an extremely rare occurrence on children or adolescents [3,5,6].About gender, GBMO has been said as more prevalent in men at a 3,25:1 rate [3], but this prevalence is controversial, since many time GBMO is still misdiagnosed as a regular GBM or as anaplastic oligoastrocytoma (AOA). However, Karsy et al showed the rarity of this subtype of GBM and, moreover, how rare is its occurrence in children and adolescents [6].In Brazil, literature about GBMO is scarce, although some cases of GBMs have been reported, most of it was in adults and located in the cerebellum [7]. Furthermore, cases related regarding specifically pediatric patients include a cerebral case, located in the right hemisphere [8].How...