Metastatic Merkel-cell carcinoma: the dawn of a new era.

Merkel-cell carcinoma (MCC) is a rare but aggressive cutaneous malignancy arising most often in sun-exposed Caucasians who are immunosuppressed or the elderly. Patients with metastatic disease treated with chemotherapy have a median progression-free survival of just 3 months. This report describes a 58-year-old man with a background history of psoriasis treated with immunosuppressive therapy and subsequently diagnosed with metastatic MCC. Chemotherapy produced a partial response. Then, a novel immunotherapy agent, pembrolizumab, induced a complete response maintained for at least 19 months. Quality of life was unaffected, and toxicity from immunotherapy was minimal. At the time of writing, there was no clinical or radiological evidence of recurrence and treatment is ongoing.