髓母细胞瘤是儿童后颅凹常见的恶性肿瘤。Hope—Stone报告,发病率约占儿童恶性疾患10%,顾绥嶽等对721例小儿恶性肿瘤统计分析中发现髓母细胞瘤占小儿恶性肿瘤的8.3%,Aron报告,本病占儿童脑肿瘤的18—35%。我科自1967年3月至1975年2月共收15岁以下做放射治疗的儿童恶性肿瘤254例,其中髓母细胞瘤18例,占7.1%。此肿瘤常常浸润蛛网膜下腔,有一个明显地经脑脊液途径转移到中枢神经系统其他部位 Medulloblastoma is a common malignant tumor in the posterior fossa of children. Hope-Stone reported that the incidence of children accounted for about 10% of malignant disease, Gu Suiyue and other 721 cases of pediatric malignancies in the statistical analysis of medulloblastoma accounted for 8.3% of pediatric malignancies, Aron reports, the disease accounted for 18 cases of brain tumors in children -35%. Our department from March 1967 to February 1975 received a total of 254 cases of children under the age of 15 undergoing radiotherapy of malignancies, including medulloblastoma in 18 cases, accounting for 7.1%. This tumor often infiltrating the subarachnoid space, there is a clear route by cerebrospinal fluid to other parts of the central nervous system