横纹肌肉瘤在光镜下一般可分为腺泡型、胚胎型及多形型3种,其中前两型的诊断常遇到困难。特别是在肿瘤完全不具横纹肌母细胞分化的趋向,虽经磷钨酸苏木素等特殊染色也不能见到瘤细胞有横纹出现时,往往不能作出确切诊断,而需要用电镜和/或免疫组化方法以确诊。本文将经电镜及免疫过氧化酶方法确诊为腺泡型横纹肌肉瘤的一例报告于后,并对其鉴别诊断加以讨论。 Rhabdomyosarcoma is generally classified into acinar, embryonic, and polymorphic types under light microscopy, and the diagnosis of the first two types often encounters difficulties. Especially in tumors that do not have the tendency to differentiate into rhabdyosarcoma cells in spite of the fact that specific staining with phosphotungstic acid hematoxylin and other tumors do not show the appearance of transverse stripes, they often cannot make a definitive diagnosis. Electron microscopy and/or immunohistochemistry are required. Methods to confirm the diagnosis. In this paper, one case of alveolar rhabdomyosarcoma diagnosed by electron microscopy and immunoperoxidase method was reported later, and its differential diagnosis was discussed.