Merkel cell carcinoma (MCC) is a rare neuroendocrine tumor of the skin associated with a high risk of local recurrence and distant metastases. It most commonly occurs on sun-exposed areas of white patients >65 years of age. The Merkel cell polyomavirus (MCV) is thought to be responsible for malignant transformation in approximately 80% of cases in the northern hemisphere, while ultraviolet radiation–induced DNA damage is implicated in MCV-negative tumors. The overall incidence of MCC is low, with approximately 1600 cases diagnosed annually in the United States. The rate is much higher in patients with lymphoproliferative malignancies, solid organ transplants, and HIV infection. The low overall incidence of this tumor makes it challenging to conduct prospective clinical trials with sufficient power. As a result, most management recommendations are based on case series, retrospective reviews, and expert opinion. The pathogenesis, diagnosis, and staging of MCC was discussed in the first article in this continuing medical education series. This article focuses on current management guidelines and promising new therapies in development. Because of the complexity, aggressive nature, and individuality of each case, MCC is best treated by a multidisciplinary team.

默克尔细胞癌（MCC）是一种罕见的皮肤神经内分泌肿瘤，伴有局部复发和远处转移的高风险。它最常发生在65岁以上的白人患者的阳光照射区域。在北半球大约80％的病例中，默克尔细胞多瘤病毒（MCV）被认为是导致恶性转化的原因，而MCV阴性肿瘤与紫外线辐射引起的DNA损伤有关。MCC的总发病率很低，在美国每年大约诊断1600例。患有淋巴增生性恶性肿瘤，实体器官移植和HIV感染的患者的发病率要高得多。该肿瘤的低总发病率使得以足够的力量进行前瞻性临床试验具有挑战性。因此，大多数管理建议均基于案例系列，回顾性审查和专家意见。在此继续医学教育系列的第一篇文章中讨论了MCC的发病机制，诊断和分期。本文重点介绍当前的管理指南和发展中有希望的新疗法。由于每种情况的复杂性，攻击性和个性，MCC最好由多学科团队处理。