Merkel细胞癌3例临床与病理分析

Merkel Cell Carcinoma: A Clinicopathological Analysis of 3 cases

目的探讨Merkel细胞癌的临床与病理特点、病因学、诊断及鉴别诊断。方法观察3例Merkel细胞癌的组织病理特点和免疫组化染色结果,并复习相关文献。结果 3例均为老年患者,女2例,男1例。镜下见肿瘤主要位于真皮,呈巢索状和弥漫片状分布,癌细胞圆形、卵圆形或梭形,大小及形态较一致,胞质较少,核染色质细颗粒状,病理性核分裂像多见。免疫组化见CK20和神经内分泌标记阳性,HMB45,TTF-1,LCA和CD99等阴性。结论 Merkel细胞癌是一种发生于皮肤的少见的高度恶性神经内分泌肿瘤,易局部复发或转移。近年来发现的Merkel细胞多瘤病毒可能是其重要的致病因子。其临床病理及特征性的免疫组化表达有助于诊断及鉴别诊断。目前的治疗方法主要有手术切除和辅助放疗及化疗。

Objective To explore the clinicopathological feature, epidemiology, diagnosis, and differential diagnosis of the Merkel cell carcinoma （MCC）. Methods Histopathological characteristics and immunohistochemical expression were investigated on three cases of Merkel cell carcinoma with review of the literatures. Results Of the three aged patients, two were females and one was male. Microscopically, MCC arose in the dermis. The tumor cells showed a nest-like structure or diffused pattern with uniformly round, oval or spindle shape and little cytoplasm. Mitotic figures were observed fi＇equently. MCC was positive for CK20 and classic neuro- endocrine markers but negative for HMB45, TFF-I, LCA, CD99. Conclusion Merkel cell carcinoma is a rare but very aggressive cutaneous neuroendocrine carcinoma. It tends to local recurrent and metastasis. The recent identification of the Merkel cell polyomavirus has been implicated in the pathogenesis of MCC. The di- agnosis can be made by the combination of the clinicopathological features and distinctive immunohistochemi- cal expression. Surgical excision is the treatment of choice, but adjuvant radiation therapy and chemotherapy have also found to be effective.