A rare case of high-grade diffuse glioneuronal tumor treated with VMAT radiotherapy.

Glioneuronal tumors are a very rare type of central nervous system (CNS) tumors. Due to rarity, even literature is limited. There is inconsistency in literature with respect to prevalence in different age groups, sex predilection, and treatment. Diagnosis of diffuse glioneuronal tumors is based on both radiologic and histopathologic features. Radiologically, they are often large, ill-defined lesions. On immunohistochemistry, the are positive for glial fibrillary acidic protein (GFAP), OLIG2, S100, and synaptophysin and negative for IDH1. Recently, glioneuronal tumors are included in the 2016 World Health Organization (WHO) classification of CNS neoplasms; however, there are many cases of glioneuronal tumors with distinctive morphologic features that are still not formally included in any classification. Similarly, there is vast disparity between treatments in various literature reports, ranging from surgery to chemoradiation to craniospinal irradiation. Here, we are presenting a case of high-grade diffuse glioneuronal tumor in a 28-year-old male. We have described the radiologic and pathologic features in our case. He was treated with volumetric modulated arc technique (VMAT) radiotherapy and concurrent chemotherapy.