Coexistence of head and face Merkel cell and squamous cell carcinomas in the elderly population - a case report and literature review.

Merkel cell carcinoma (MCC) is a rare and highly aggressive neuroendocrine cancer type that predominantly impacts sun-exposed skin areas in the elderly, particularly the head and neck (41-50%), followed by the limbs (32-38%). There is likely an association between MCC and other cutaneous malignancies, such as cutaneous squamous cell carcinoma (CSCC), Bowen's disease, and basal cell carcinoma. Cutaneous squamous cell carcinoma is the most common concurrent tumor with MCC, especially in sun-exposed regions of the skin. Herein, we present a case of coexistence of MCC and CSCC in the craniofacial region, accompanied by an extensive review of relevant literature on this topic.