髓上皮瘤是源自神经系统的一种少见的恶性肿瘤，多发生在中枢神经系统和睫状体，而源自视神经的恶性髓上皮瘤则很少见，国内尚未有病例报道。此病早期类似胶质瘤，易造成误诊。本文报道了 1 例 3 岁 10 个月的男性患儿，经部分肿物切除活检发现肿瘤具有典型恶性髓上皮瘤的病理特点， 部分瘤细胞向软骨细胞分化，并逐渐形成透明软骨岛，NSE 及 S-100 表达阳性，病理诊断为源自视神经的畸胎性恶性髓上皮瘤。

       Medulloepithelioma is a clinically uncommon tumor originated from nervous system, often occurred in central nerve system and ciliary body, and malignant medulloepithelioma of the optic nerve is far rarer. So far, there has been no case report in China. It may be clinically misdiagnosed because it resembles glioma at the early stage of the disease. We reported a boy with a tumor in his right eye at age of 3.8 years, which was shown by biopsy of the partial tumor that there were some obviously heteromorphous neoplastic cells, karyokinesis, and moreover, some neoplastic cells differentiatied into cartilage cells, gradually formed into hyaline cartilage islands and the expressions of NSE and S-100 were positive. Teratoid malignant medulloepithelioma of optic nerve was made pathologically.