A case of complete spontaneous regression of extremely advanced Merkel cell carcinoma.

Merkel cell carcinoma (MCC) is a rare locally malignant cutaneous tumor of neuroendocrine origin, most often occurring on the head and neck of the elderly. MCC is a highly aggressive tumor with a high percentage of recurrence, metastatic spread and mortality. Despite the highly malignant course of MCC, there have been several reports of spontaneous regression or resolution. We report the clinical course of a 71-year-old man with MCC. The tumor initially occurred in the left lower eyelid and advanced to encompass nearly half the face. Despite its large size, complete spontaneous regression of the tumor occurred. This is the most advanced case of complete spontaneous regression of MCC to be reported.