Merkel Cell Carcinoma Masquerading Clinically as a Cyst in a Young Patient.

Merkel cell carcinoma (MCC) is an extremely rare and aggressive tumor. Here we report an unusual MCC that manifested as an abruptly enlarging, painful skin lesion over the right antecubital fossa and masqueraded as an epidermal cyst in a 42-year-old male. The lesion was surgically excised and subjected to histopathologic and immunohistochemical examinations.