Abstract:

Background and purpose: Extraskeletal myxoid chondrosarcoma (EMC) is a malignancy of uncertain differentiation tumor characterized by a multinodular structure and abundant myxoid matrix. Its preferred sites were the deep soft tissues of the extremities. The aim of this study was to investigate the clinicopathologic characteristics, diagnosis and differential diagnosis of EMC. Methods: Seven cases of EMC were analyzed for clinicopathological and immunohistochemical features with review of the related literature. Results: It occurred predominantly in females (male/female=2︰5). Five cases were located in low extremities and two in upper limb girdles, more commonly near the joint. Grossly, the masses showed as grey, lobular and somewhat transparent with a relatively well–defined margin. Microscopically, the small ovary or plump spindle–shaped cells arranged in strand and cord patterns and lobular architecture which separated by delicate fibrous networks with an abundant myxoid but hypovascular background. And the tumors were immunoreactive for vimentin, and partly for S-100 and EMA, meanwhile, negative for CK. Conclusion: EMC is a rare soft tissue sarcoma with distinctive histopathological features. It should be distinguished from some mimics especially those tumors with a myxoid stroma or chondroid differentiation,such as chordoma and chondrosarcoma. 　

Key words: Soft tissure neoplasm, Extraskeletal myxoid chondrosarcoma, Clinicopathology, Differential diagnosis