DIPG-25. RELATIONSHIP BETWEEN MOLECULAR CLASSIFICATION, ORIGIN AND PROGNOSIS IN DIFFUSE MALIGNANT GLIOMA IN CHILDREN

Abstract

Abstract INTRODUCTION Diffuse malignant gliomas that occurs in childhood is recognized as a biologically different disease from that in adults. Furthermore, with the recent development of molecular diagnostics, diffuse midline glioma (DMG), which occurs mainly in the thalamus and brainstem, frequently occurs in childhood and have poor prognosis. We report the relationship between imaging findings, origin, and prognosis of diffuse malignant glioma in children or young adult based on our case series. PATIENTS AND METHODS 43 cases of malignant glioma that occurred from childhood to young adult (below 30 years old) and were treated at our hospital since 2004 were registered in the analysis. Of the 42 cases, 24 cases were in brain stem, 11 cases in cerebral hemisphere, 6 cases in thalamus, and 1 case in cerebellar hemisphere. Histological diagnosis was possible in 31 cases, but without histological verification in 11 brain stem lesions. Histological diagnosis included 13 high-grade glioma (GBM, including NOS and G34R mutations), 11 DMG, and 7 anaplastic astrocytoma. RESULTS Of 13 cases of hemispheric high-grade gliomas, 2 cases had long-term survival (both cases received WT1 peptide vaccination), and 1 case survived for more than 5 years (total resection, MGMT methylation). Among the DMGs, 7 cases were found in brain stem (5 pons, 2 pontomedullary junction, 1 cerebellar peduncle, and 1 midbrain), 3 cases in the thalamus. Two cases of onset at the pontomedullary junction were found incidentally, and the symptoms gradually increased during follow-up, and multidisciplinary treatment was performed. Bilateral thalamus DMG with HIST1H3B mutation showed slowly growing and invasion. SUMMARY There were cases of pediatric hemisphere glioblastoma with long-term survival. In addition, the origin and imaging findings of DMG were various, and tumors that originate at the pontomedullary junction may be relatively favorable.