Objective: To investigate the clinicopathological features, differential diagnosis and prognosis of Merkel cell carcinoma (MCC). Methods: The clinical and pathological data of 10 patients with MCC were collected at the 940th Hospital of PLA. The histological characteristics were examined. Immunohistochemical EnVision method was used to detect thyroid transcription factor-1 (TTF1), broad-spectrum cytokeratin (CKpan), CK20, S-100, Ki-67, CD56, chromogranin A, synaptophysin and other markers in the 10 cases. Results: Intradermal MCC of the skin showed a nested, cord-like, cribriform distribution, polygonal cells, uniform size, and lack of cytoplasm. Tumor cell nuclei were large and round, with clear nuclear membranes, fine and scattered chromatin, absence of nucleoli, and mitotic figures of 10 per 50 high power fields. Among them, one patient had sarcoma and squamous cell carcinoma in situ, one patient had squamous cell carcinoma in situ, and one patient had unique cell morphology. Immunohistochemical staining showed that all cancer cells expressed CKpan, synaptophysin and CD56. There were seven cases with perinuclear dot-like positivity of CK20. Six MCCs expressed chromogranin A to varying degrees, while 2 MCCs were weakly positive for p63. The nuclear positive index in the Ki-67 hotspot area was 60%. Conclusion: The histology of MCC varies. Rendering a correct diagnosis of MCC requires adequate sampling, close correlation with clinical history and rational use of immunohistochemical staining. The treatment requires standardized surgery, postoperative radiotherapy and multimodal chemotherapy. Immunotherapy may replace the traditional treatment in the future.
目的： 对Merkel细胞癌（Merkel cell carcinoma，MCC）的临床病理学特征、鉴别要点以及预后进行探讨和分析。 方法： 收集2013年2月至2020年5月解放军联勤保障部队第940医院诊断的10例MCC患者的临床及病理检查资料，观察其组织形态学特点，采用免疫组织化学EnVision两步法检测，对10例行甲状腺转录因子1（TTF1）、广谱细胞角蛋白（CKpan）、细胞角蛋白（CK）20、S-100蛋白、Ki-67、CD56、嗜铬粒素A（CgA）、突触素等多种标志物染色。 结果： 镜下见经典型癌细胞主要位于真皮，呈梁状、巢团状、缎带样或彩带样结构。细胞多角形，大小一致，缺乏胞质。核大、圆形、类圆形，细胞核膜清晰，染色质细而散布，核仁缺如，核分裂象约10个/50 HPF。其中1例合并肉瘤及原位鳞状细胞癌，1例合并原位鳞状细胞癌，1例具有独特的细胞形态。免疫组织化学染色结果示癌细胞均表达CKpan、突触素和CD56，有7例CK20呈核周逗点状阳性，6例不同程度表达CgA，2例p63弱阳性，Ki-67热点区核阳性指数为60%。 结论： MCC的组织形态比较复杂，正确诊断需要充分取材、紧密结合临床病史及合理应用免疫组织化学染色，治疗需要规范手术、术后放疗和化疗形式的多模式，未来免疫治疗将可能替代传统治疗。.