作者对一例少见的复发性胎儿横纹肌瘤进行了组织形态学、免疫组织化学和超微结构的研究。结果表明原发和复发肿瘤均主要由未分化的间叶细胞、肌母细胞和幼稚的横纹肌细胞组成。肿瘤细胞呈漩涡状、栅栏状和束状密集排列，肌母细胞和横纹肌细胞主要排列于肿瘤周缘，其ＭＧ和Ｍａｃｔｉｎ染色均阳性。电镜下可见胞浆内有肌原纤维、幼稚的Ｚ线及原始肌节。该肿瘤尽管有包膜，但在包膜外也可见肿瘤细胞浸润。肿瘤中尚见有多量骨样组织及富于血管粘液的区域。文中还对该肿瘤与纤维肉瘤、血管外皮瘤、蝾螈瘤以及分化好的横纹肌肉瘤的鉴别诊断以及对其生物学行为进行了讨论。作者认为胎儿横纹肌瘤虽属良性肿瘤，但有一定的复发和恶性改变倾向，故临床治疗时应视其为临界瘤来处理。 The author of a rare case of recurrent fetal rhabdomyoma histomorphology, immunohistochemistry and ultrastructure of the study. The results showed that primary and recurrent tumors are mainly composed of undifferentiated mesenchymal cells, myoblasts and naive striated muscle cells. Tumor cells were swirling, palisading and bundles densely arranged. Myoblasts and striated muscle cells were mainly located in the periphery of the tumor, and both MG and Mactin staining were positive. Electron microscope shows intracytoplasmic myofibrillar, naive Z-line and the original sarcomere. Although the tumor has an envelope, tumor cell infiltration can be seen outside the envelope. There are still a lot of tumor-like bone tissue and vascular mucus area. The article also on the tumor and fibrosarcoma, hemangiopericytoma, salamander tumor and differentiated rhabdomyosarcoma, the differential diagnosis and its biological behavior were discussed. The authors believe that although the fetal rhabdomyoma is a benign tumor, but there is a certain tendency of recurrence and malignant transformation, it should be treated as a critical tumor for clinical treatment.