Tsuchida R, Ishida T, Uozaki H, Bessho F, Machinami R
Department of Pathology, Faculty of Medicine, University of Tokyo, Japan.
Ultrastruct Pathol. 1999 May-Jun;23(3):193-8. doi: 10.1080/019131299281707.
This study presents a case of embryonal rhabdomyosarcoma (ERMS) of the forearm soft tissue in a 12-year-old female, in which microtubular aggregates in rough endoplasmic reticulum (rER) were noted ultrastructurally. Histologically, tumor cells consisted of typical rhabdomyoblastoid cells with abundant eosinophilic cytoplasm and relatively immature, small tumor cells. Ultrastructurally, two different types of tumor cells were also identified by light microscopy. More than half the tumor cells possessed the characteristic features of rhabdomyoblastic differentiation, such as abundant thick and thin filaments with Z-bands. The other tumor cells were less differentiated cells in which microtubular aggregates (MA) in rER were observed. MA in rER have been described in several nonepithelial tumors, including malignant melanoma, osteosarcoma, extraskeletal myxoid chondrosarcoma, and chordoma. ERMS is another example of mesenchymal tumor in which MA in rER are observed by electron microscopy. Considering the differential diagnosis among mesenchymal tumors, it is important to know that MA can be also observed in ERMS.
本研究报告了一例12岁女性前臂软组织胚胎性横纹肌肉瘤（ERMS），超微结构观察发现粗面内质网（rER）中有微管聚集。组织学上，肿瘤细胞由典型的横纹肌母细胞样细胞组成，胞质嗜酸性丰富，还有相对不成熟的小肿瘤细胞。超微结构上，通过光学显微镜也识别出两种不同类型的肿瘤细胞。超过半数的肿瘤细胞具有横纹肌母细胞分化的特征，如大量粗细肌丝伴Z带。其他肿瘤细胞为分化较差的细胞，其中观察到rER中有微管聚集（MA）。rER中的MA已在几种非上皮性肿瘤中被描述，包括恶性黑色素瘤、骨肉瘤、骨外黏液样软骨肉瘤和弦瘤。ERMS是通过电子显微镜观察到rER中有MA的间叶性肿瘤的又一实例。考虑到间叶性肿瘤的鉴别诊断，了解MA也可在ERMS中观察到很重要。
