Adult Diffuse Astrocytoma in the Medulla Oblongata: Molecular Biological Analyses Including H3F3A Mutation of Histone H3.3

Abstract

Unlike in children, brain stem gliomas in adult are rare and still poorly understood. In addition, most adult brain stem gliomas result predominantly in the pons and are less often found in the medulla oblongata. Here, we report a case of an adult glioma in the medulla oblongata and its molecular biological features. A 46-year-old male presented with gait disturbance, paresthesia, and dysphagia. Magnetic resonance imaging (MRI) showed a diffuse hyper-intensive lesion in the medulla oblongata on a T2-weighted image without gadolinium contrast enhancement. We performed an open biopsy and the lesion was pathologically diagnosed as a diffuse astrocytoma. Molecular biological analyses revealed the absence of histone H3.3 mutation (H3F3A K27M), and presence of methylation of O-6-methylguanine-DNA methyltransferase (MGMT) promoter and a mutation in isocitrate dehydrogenase 1 (IDH-1). The patient received local radiotherapy and temozolomide chemotherapy. The patient’s symptoms were ameliorated, and MRI showed no tumor growth at 6 months after the initial treatment. Biopsy for brain stem lesions is generally thought to have risk of complications, but if performed minimally, it is useful to diagnose and determine treatment strategy. Obtaining patient characteristics and molecular biological features will provide insight towards therapeutic treatment for adult brain stem gliomas.

IDH-mutant Astrocytoma Arising in the Brainstem with Symptom Improvement by Foramen Magnum Decompression: A Case Report

“…Among the cases, there have been four reports of diffuse astrocytoma, and chemoradiation was the main treatment. 19,[21][22][23] While these treatments should be considered in terms of tumor control, the longterm effects of treatments including radiation and chemotherapy need to be examined. 24) The patient described herein is being kept under observation, considering the slow rate of tumor progression and the fact that she is currently asymptomatic and willing to be observed.…”