Radiation therapy-induced high-degree gliomas (RIGs) are a rare complication with an ominous prognosis. Little is known about the underlying biology of RIGs, although some studies have suggested that there are no unique histologic or cytogenetic features to distinguish them from de novo glioblastomas. Two cases that meet the criteria to be considered RIG are reported, and pertinent pieces of literature are discussed. Two patients under 10 years of age, neither of whom had relevant genetic or clinical history, were diagnosed with primary cerebral gliomas at the National Institute of Neoplastic Diseases in Lima and, after radiation therapy cycles, developed high-degree secondary gliomas, confirmed in both patients by a histopathologic analysis. This report emphasizes the need to identify risk factors, molecular mechanisms of tumor development after radiotherapy, and probable therapeutic ta...

Background: A high frequency of primary central nervous system (CNS) sarcomas was observed in Peru. This article describes the clinical characteristics, biological characteristics, and outcome of 70 pediatric patients. Methods: Data from 70 pediatric patients with primary CNS sarcomas diagnosed between January 2005 and June 2018 were analyzed. DNA methylation profiling from 28 tumors and gene panel sequencing from 27 tumors were available. Results: The median age of the patients was 6 years (range, 2-17.5 years), and 66 of 70 patients had supratentorial tumors. DNA methylation profiling classified 28 of 28 tumors as primary CNS sarcoma, DICER1 mutant. DICER1 mutations were found in 26 of 27 cases, TP53 mutations were found in 22 of 27 cases, and RAS-pathway gene mutations (NF1, KRAS, and NRAS) were found in 19 of 27 tumors, all of which were somatic (germline control available in 19 case...