An Unusual Morphological Presentation of Cutaneous Squamous Cell Carcinoma Mimicking Microcystic Adnexal Carcinoma: A Diagnostic Pitfall.

Cutaneous squamous cell carcinoma (SCC) exhibiting microcystic adnexal carcinoma-like differentiation is an extremely rare tumor that shows both squamous and ductal differentiation. This tumor is often misdiagnosed clinically and histologically and is confused with other malignant and benign cutaneous neoplasms. It usually occurs in middle-aged to older adults. Here, we report a case of SCC with microcystic adnexal carcinoma-like differentiation on the left chin of a 71-year-old male. The histopathological examination revealed a nodular tumor infiltrating the dermis, subcutaneous fat, and striated muscle tissue, consisting of both prominent atypical squamous differentiation and foci of duct-like structures.