原始神经外胚层肿瘤(PNET)是起源于原始神经管胚基细胞的末分化的高度恶性幕上肿瘤。按照WHO新的脑肿瘤分类,PNET为小脑成髓细胞瘤和在组织学上难与成髓细胞瘤区分的小脑外中枢神经系统内的一类肿瘤。尽管这类肿瘤与后颅窝肿瘤有某些相似之处,但在自然病程及对治疗的反应方面有重要不同。幕上PNET主要见于儿童,可沿脑脊 The primitive neuroectodermal tumor (PNET) is a terminal differentiated, highly malignant supratentorial tumor that originates from primitive neural tube embryonic germ cells. According to the new WHO classification of brain tumors, PNET is a type of tumor within the cerebellar medulloblastoma and within the extra-cerebellar central nervous system that is histologically difficult to differentiate from myeloblastoma. Although there are some similarities between this type of tumor and posterior fossa tumors, there are important differences in the natural history and response to treatment. On the screen PNET mainly seen in children, along the cerebrum