Merkel cell carcinoma (MCC) is an uncommon primary cutaneous neuroendocrine cancer. It most commonly presents as an indurated plaque or nodule on sun-damaged skin in elderly patients and is characterized by high rates of local recurrence and nodal metastasis. Survival at 5 years is 51% for local disease and as low as 14% for distant disease, which underscores the aggressive nature of this tumor and challenges in management. Advances in immunology and molecular genetics have broadened our understanding of the pathophysiology of MCC and expanded our therapeutic arsenal. With this comprehensive review, we provide an update of MCC epidemiology, pathogenesis, clinical presentation, diagnostic evaluation and prognostic markers. The second article in this continuing medical education series explores the evolving landscape in MCC management.

默克尔细胞癌（MCC）是一种罕见的原发性皮肤神经内分泌癌。在老年患者中，它最常表现为在日光照射下的皮肤上形成硬结斑块或结节，其特点是局部复发和淋巴结转移率高。局部疾病在5年生存率是51％，而远处疾病则低至14％，这突显了这种肿瘤的侵略性和管理上的挑战。免疫学和分子遗传学方面的进展拓宽了我们对MCC病理生理学的理解，并扩大了我们的治疗武库。通过这次全面的审查，我们提供了MCC流行病学，发病机制，临床表现，诊断评估和预后指标的更新。该继续医学教育系列的第二篇文章探讨了MCC管理中不断发展的前景。