Giant metastatic Merkel cell carcinoma.

A 68-year-old man presented with a rapidly growing, asymptomatic mass on his left mid-back for the past 3 months. The patient's medical history revealed an intentional 60-pound weight loss over the previous 2 years along with smoking approximately 1 pack of cigarettes per day. On physical examination, a fungating, 11-cm red tumor with palpable broader underlying extension (23 cm total) was present on the left mid-back with distinct red dermal nodules in a dermatomal distribution. In close proximity were two ulcerated nodules, proven histologically to be basal cell carcinomas. In the left groin was massive, fixed lymphadenopathy. A punch biopsy of the tumor was performed, which showed a dense infiltrate of small, round hyperchromatic blue cells that stained positive for CD 56 and pancytokeratin in a perinuclear dot pattern. Tumor cells were negative for CK20, TTF, CK7, and LCA.