Reith J D, Bauer T W, Fischler D F, Joyce M J, Marks K E
Department of Anatomic Pathology, Cleveland Clinic Foundation, OH 44195, USA.
Am J Surg Pathol. 1996 Mar;20(3):293-8. doi: 10.1097/00000478-199603000-00005.
Dedifferentiated chondrosarcomas are primary bone tumors characterized by the presence of both low-grade cartilaginous and high-grade sarcomatous components. The high-grade component usually shows histologic features of either malignant fibrous histiocytoma or fibrosarcoma. We are aware of only 10 published cases in which the high-grade component showed rhabdomyosarcomatous differentiation. To further clarify the clinical, radiographic, and pathologic features of this unusual variant, we report three additional cases of dedifferentiated chondrosarcoma with rhabdomyosarcomatous differentiation. The patients included two men and one woman; their mean age was 63 years. Tumors originated in the pelvis (ilium), scapula, and tibia. Two patients presented with radiographic findings typical of dedifferentiated chondrosarcoma, including a geographic, lytic lesion with areas of mineralization suggestive of cartilage in close association with a permeative component. The third patient presented with a primarily lytic, destructive lesion of the right iliac wing. Histologically, the tumors contained lobules of well-differentiated chondrosarcoma associated with a high-grade sarcoma with prominent rhabdomyoblasts. Immunohistochemical stains for actin and desmin were positive in all three tumors, and electron microscopy revealed evidence of skeletal muscle differentiation. All three patients died with metastatic disease, 1, 6, and 12 months postoperatively. This histologic variant of dedifferentiated chondrosarcoma is rare, but it shows radiographic and clinical features similar to "conventional" dedifferentiated chondrosarcoma, including a very poor prognosis.
去分化软骨肉瘤是一种原发性骨肿瘤，其特征是同时存在低级别软骨成分和高级别肉瘤成分。高级别成分通常表现出恶性纤维组织细胞瘤或纤维肉瘤的组织学特征。我们仅知晓10例已发表的病例，其中高级别成分显示出横纹肌肉瘤分化。为进一步阐明这种不寻常变体的临床、影像学和病理特征，我们报告另外3例具有横纹肌肉瘤分化的去分化软骨肉瘤病例。患者包括2名男性和1名女性；他们的平均年龄为63岁。肿瘤分别起源于骨盆（髂骨）、肩胛骨和胫骨。2例患者的影像学表现为典型的去分化软骨肉瘤，包括一个边界清晰的溶骨性病变，伴有提示软骨的矿化区域，并与浸润性成分紧密相关。第3例患者表现为右髂骨翼的主要为溶骨性、破坏性病变。组织学上，肿瘤包含分化良好的软骨肉瘤小叶，伴有具有显著横纹肌母细胞的高级别肉瘤。所有3例肿瘤的肌动蛋白和结蛋白免疫组化染色均为阳性，电子显微镜检查显示有骨骼肌分化的证据。所有3例患者均在术后1、6和12个月死于转移性疾病。这种组织学变体的去分化软骨肉瘤很罕见，但它显示出与“传统”去分化软骨肉瘤相似的影像学和临床特征，包括预后极差。
