骨外黏液样软骨肉瘤研究进展

骨外黏液样软骨肉瘤（ex-traske-letal myxoid chondrosarcoma,EMC）是一类罕见的软组织恶性肿瘤,主要发生于四肢深部。其组织病理学为分叶状结构,肿瘤细胞排列成丝带状由小叶周边向中心放射状分布;电镜下部分肿瘤细胞质内可见神经内分泌颗粒;免疫组化显示肿瘤细胞表达波形蛋白（vi mentin）,部分表达NSE、Syn、CgA及S-100,CK和EMA可灶性表达于上皮样分化区。其粘液样基质奥新兰染色阳性,并抗透明质酸酶。由于该肿瘤生长缓慢,局部复发率高,使肿瘤细胞发生退变或间变,从而形成复杂的病理组织学图像,极易造成病理诊断错误,须与骨黏液样软骨肉瘤、脊索瘤及软组织多种黏液性肿瘤鉴别。由于该肿瘤有特异性的细胞遗传学改变,因此,目前主要研究方向为筛选出最为特异性的肿瘤融合基因作为病理诊断指标,并找出基因治疗的有效途径。

Progress of extraskeletal myxoid chondrosarcoma

Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft-tissue sarcoma that occurs primarily in the deep extremities. The histopathology of EMC shows a lobulate pattern, in which rounded and elongated cells arrange in strands and cords in a myxoid background matrix. Ultrastructurally, neuroendocrine granules can be found in part of tumor cells. Immunohistochemically, the tumor cells are diffusely positive for vimentin and partly positive for neuron specific enolase, chromogranin A, synaptophysin and S-100 protein. The tumor cells in epithelioid foci can also express cytokeratin and epithelial membrane antigen. The myxoid matrix can be stained with alcian blue and this reaction is resistant to prior treatment with hyaluronidase. The characteristic clinical features of EMC are slowing growth and local recurrence in high rate, which makes the tumor cells degenerated or dedifferentiated. The histopathologic variability and multidirectional differentiation of EMC always confuse pathologists. The histological differential diagnosis includes skeletal myxoid chondrosarcoma, chordoma and soft tissue tumors with a myxoid stroma among others. Because EMC has specific molecular genetic characteristics, most studies at present are focused on selecting out the most specific tumor fusion genes as pathological diagnostic markers and potential therapeutic targets.