Pigmented squamous cell carcinoma.

Although dendritic, melanin-containing melanocytes can be seen in a variety of epithelial neoplasms, only 0.01% to 7% of all squamous cell carcinomas (SCC) are pigmented. Furthermore, most reported cases have occurred in the oral and ocular mucosa, with relatively few cases reported to originate in the skin. Herein we report a case of a 61-year-old Caucasian male who presented with a large blue-black nodule on his left cheek, clinically suspicious for a melanoma; however, histological evaluation revealed an acantholytic pigmented squamous cell carcinoma. Previous cases are reviewed and the clinical and histological differential diagnoses are discussed.