骨外黏液样软骨肉瘤一例临床分析

Extraskeletal Myxoid Chondrosarcoma:Report of One Case and Review of Literatures

骨外黏液样软骨肉瘤(EMC)是一类罕见的恶性软组织肿瘤,主要发生于四肢深部。光镜下肿瘤呈分叶状,边界清,细胞为圆形、短梭形,或束状排列于黏液样基质中,电镜下部分肿瘤细胞质内有神经内分泌颗粒,免疫组化显示肿瘤细胞表达Vimentin及S-100,其黏液样基质澳新兰染色阳性,并抗透明质酸酶。因肿瘤生长缓慢,复发率高,易发生退变或间变,形成复杂的病理组织学图像,易造成病理诊断错误,诊断主要依靠发生部位和组织病理学特征,免疫组化标记可帮助诊断和鉴别诊断,应与骨黏液样软骨肉瘤、脊索瘤、软组织多种黏液性肿瘤鉴别。本文就一例骨外黏液样骨肉瘤的临床资料结合文献进行分析。

Extraskeletal myxoid chondrosarcoma（EMC）is a rare soft-tissue sarcoma that occurs primarily in the deep extremities.Microscopically,the neoplasms were relatively well circumscribed and composed of round and elongated cells arranged in strands and cords in a myxoid background.Ultrastructurally,neuroendocrine granules can be found in part of tumor cells.Immunohistochemically,the tumor cells are diffusely positive for vimentin and S-100 protein.The myxoid matrix can be stained with alcian blue and this reaction is resistant to hyaluronidase.The clinical features of EMC are slowing growth and local recurrence in high rate,which makes the tumor cells degenerated or de-differentiated.The histopathologic variability and multidirectional differentiation of EMC always confuse pathologists.Its diagnosis mainly depends on the involved site and histopathologic feature.Immunohistochemistry is helpful for diagnosis and differential diagnosis.The histological differential diagnosis includes skeletal myxoid chondrosarcoma,chordoma and soft tissue tumors with a myxoid stroma among others.