Scatena Cristian, Massi Daniela, Franchi Alessandro, De Paoli Antonino, Canzonieri Vincenzo
Division of Pathological Anatomy, Department of Critical Care Medicine and Surgery, University of Florence, Florence, Italy.
Am J Dermatopathol. 2012 Feb;34(1):e1-6. doi: 10.1097/DAD.0b013e31822381fas.
Rhabdomyosarcomas (RMSs) are soft tissue sarcomas with skeletal muscle differentiation. Cutaneous RMSs are exceedingly rare, and in most cases, they represent metastatic disease or the dermal involvement by a tumor arising in the underlying soft tissues. We herein report the case of a 41-year-old man who developed a cutaneous swelling of the right nasal orbital angle. An initial incisional biopsy showed cytokeratin-positive atypical spindle cells forming long and intersecting fascicles, thus the case was diagnosed as carcinosarcoma. In the subsequent excisional biopsy, the skeletal myogenic differentiation of the tumor cells infiltrating the dermis and subcutis was demonstrated by morphology (presence of rhabdomyoblasts), immunohistochemistry (positivity for desmin, myogenin, myoglobin, and actins), and electron microscopy (evidence of rudimentary sarcomeric structures). A final diagnosis of primary cutaneous RMS was made. The patient was subjected to postoperative radiation and chemotherapy, but after 4 months, the patient developed a tumor recurrence followed by distant metastases and death. Review of the literature reveals that RMSs of the skin are often underrecognized and display peculiar clinical features in comparison with their more common soft tissue counterpart.
横纹肌肉瘤（RMSs）是具有骨骼肌分化的软组织肉瘤。皮肤型横纹肌肉瘤极为罕见，在大多数情况下，它们代表转移性疾病或由深部软组织肿瘤累及皮肤。我们在此报告一例41岁男性患者，其右鼻眶角出现皮肤肿胀。最初的切开活检显示细胞角蛋白阳性的非典型梭形细胞形成长而交叉的束状结构，因此该病例被诊断为癌肉瘤。在随后的切除活检中，通过形态学（存在横纹肌母细胞）、免疫组织化学（结蛋白、肌生成素、肌红蛋白和肌动蛋白阳性）和电子显微镜（存在原始肌节结构的证据）证实了浸润真皮和皮下组织的肿瘤细胞具有骨骼肌源性分化。最终诊断为原发性皮肤型横纹肌肉瘤。该患者接受了术后放疗和化疗，但4个月后，患者出现肿瘤复发，随后发生远处转移并死亡。文献回顾显示，与更常见的软组织横纹肌肉瘤相比，皮肤型横纹肌肉瘤常常未被充分认识，且表现出独特的临床特征。
