肉瘤样癌的病理诊断与鉴别诊断研究

目的 观察肉瘤样癌（SC）病理形态学特点及免疫组化表达，探讨SC的诊断与鉴别诊断。方法 对26例不同部位的SC作了光镜观察及免疫组化染色，5例作了透射电镜观察。结果 26例SC中15例双相（明确的癌和肉瘤样成分），11例单相（完全为肉瘤样成分），肉瘤样成分为梭形细胞及多形性细胞。免疫组织化学观察结果，26例SC的CK或Keratin在两种成分中均呈阳性表达。Vimentin对明确的癌成分阴性，而绝大部分肉瘤样细胞强阳性，但其阳性强度及阳性细胞数量有明显不同。CD68和HMB－45均阴性。5例电镜下瘤细胞间可见不同发育程度的桥粒连接，其中1例有张力原纤维丝。结论 SC的病理形态学是复杂的，应当与恶性纤维组织细胞瘤（MDH）、恶性黑色素瘤、纤维肉瘤、平滑肌肉瘤等鉴别。免疫组化及电镜技术对SC诊断与鉴别诊断是很有帮助的。

Pathological diagnosis and differential diagnosis of sarcomatoid carcinoma

Objective To explore the pathological and immunohistochemical features and to investigate the differential diagnosis of sarcomatoid carcinomas (SC). Methods Twenty six specimens of SC from various anatomical sites were studied with light microscopic electron microscopic examination and immunohistochemical method. Results Microscopically, 15 biphasic and 11 monophasic components of 26 cases were found with spindle cells and polymorphic cells. Desmosomes and tonofibrils were found in spindle tumor cells ultrastructurally in 5 samples, one of which having tonofibrils. Immunohistochemically cytokeratin and keratin expression of epithelial tumor cells or sarcomatoid cells were positive. Positive intensity and quantity were different from case to case. Vimentin and cytokeratin was co expressed in the sarcomatoid cells and the majority of sarcomatoid cell in all tumors was strong positive. CD68 and HMB 45 were negative reaction in SC. Conclusion Pathomorphology of SC was complicated. It must be differentiated from malignant fibrohistiocytoma (MFH), melanoma, fibrosarcoma, leiomyosarcoma etc. Immunohistochemical and ultrastructural techniques are very valuable in the differential diagnosis of SC.