Adult histone g34 mutant gliomas - a single centre experience over 10 years

AIMS Histone G-34-mutant (H3 G34) gliomas are rare, aggressive infiltrating tumours of the cerebral hemispheres and are classified as WHO grade 4 paediatric type diffuse high-grade glioma. They most commonly affect children and adolescents. We describe the clinicopathological characteristics of adult H3 G34-mutant gliomas seen at the National Hospital for Neurology and Neurosurgery over the last 10 years. METHOD We retrospectively analyzed clinic radiological data on all cases identified from the neuropathology database. Data were extracted on patient demographics, clinical and radiological features and outcome. RESULTS Six patients (2 male, 4 female) were identified, The median age of onset was 26 years (range 17-38 years). One patient presented with a Motor Neurone Disease type syndrome (progressive asymmetric spastic tetraparesis and bulbar symptoms), two with cognitive decline and three with symptoms of raised intracranial pressure. All tumours were supratentorial - 2 patients had mass lesions typical of a high-grade glioma, 1 patient had imaging features consistent with an intraventricular ependymoma. 3 patients had imaging findings that suggested a non-tumour diagnosis with extensive white matter disease more in keeping with an inflammatory demyelinating process or a leucodystrophy. The median overall survival was 23 Months (range 10 - 68 months). CONCLUSIONS Adult Histone G34-mutant gliomas have a variable presentation and are associated with a prognosis similar to other high-grade gliomas. The diagnosis should be considered in the differential of patients presenting with a predominantly white matter disorder. Multi-centre studies are needed to better delineate the phenotype and prognostic features.