Combined Neoadjuvant-Adjuvant Immunotherapy and Abdominoperineal Resection for a Primary Anorectal Melanoma: A Case Report.

Anorectal melanoma (ARM) is a rare entity with aggressive biological behavior and poor prognosis. Clinically, ARM presents with atypical symptoms, such as anal pain and bleeding, thus often being misdiagnosed as a benign anorectal pathology and leading to delayed diagnosis. We present a case of a 73-year-old female patient with stage I ARM, treated successfully with a combination of neoadjuvant-adjuvant immunotherapy (nivolumab, an anti-PD-1 monoclonal antibody) and abdominoperineal resection. The patient is disease-free at a five-year follow-up after the operation, suggesting that long-term targeted immunotherapy offers a durable and promising response. This case highlights the critical role of a multidisciplinary approach, involving specialists in ARM surgery and systemic therapies, to improve prognosis and ensure an optimal quality of life for patients with ARM. Given the limited scientific evidence, further prospective and randomized trials are required to develop effective systemic therapies and improve the survival of patients with ARM.