Trillo A A, Holleman I L, White J T
Histopathology. 1978 May;2(3):215-23. doi: 10.1111/j.1365-2559.1978.tb01711.x.
Cardiac rhabdomyoma is the most common tumour of the heart in infancy and childhood. The clinical presentation, diagnosis and histopathological characteristics have been extensively studied; however, reports on the ultrastructure and histogenesis of this lesion are scanty and inconclusive. The case to be discussed is that of a 10-year-old male who presented with a cardiac rhabdomyoma occupying almost the entire ventricular apex. Ultrastructurally, the rhabdomyoma cells have a central, deeply-indented nucleus surrounded by an admixture of mitochondria and sarcomeres. The remainder of the cytoplasm is occupied by pools of glycogen granules, randomly-orientated myofibrils and small mitochondria. Intercellular junctions are numerous and consist of alternating zonula occludens and macula adherens. Typical satellite cells, sharing a common basement lamina are seen apposed to the rhabdomyoma cells. It is tempting to postulate that the proliferation of the rhabdomyoma cells is accomplished by differentiation of satellite cells, a process known to occur in skeletal muscle. Ultrastructurally, the rhabdomyoma cells are indistinguishable from Purkinje cells. The presence of Purkinje-like cells in ectopic locations within the heart and their association with satellite cells is likely a form of embryological atavism.
心脏横纹肌瘤是婴幼儿期最常见的心脏肿瘤。其临床表现、诊断及组织病理学特征已得到广泛研究；然而，关于该病变超微结构和组织发生的报道却很少且尚无定论。本文所讨论的病例是一名10岁男性，其心脏横纹肌瘤几乎占据了整个心尖。超微结构上，横纹肌瘤细胞有一个位于中央、深陷的细胞核，周围是线粒体和肌节的混合物。细胞质的其余部分充满了糖原颗粒池、随机排列的肌原纤维和小线粒体。细胞间连接众多，由交替的紧密连接和黏着斑组成。可见典型的卫星细胞与横纹肌瘤细胞相邻，共享一层共同的基底膜。推测横纹肌瘤细胞的增殖是通过卫星细胞的分化完成的，这一过程在骨骼肌中也会发生。超微结构上，横纹肌瘤细胞与浦肯野细胞难以区分。心脏异位部位出现类似浦肯野细胞及其与卫星细胞的关联可能是一种胚胎返祖现象。
