Primary Merkel cell carcinoma of the submandibular region without cutaneous lesion: a case report.

Merkel cell carcinoma (MCC) is a rare but highly aggressive cutaneous neuroendocrine malignancy that typically arises in sun-exposed skin and may secondarily invade deeper soft tissues. Primary MCC arising from non-cutaneous structures is exceedingly uncommon. We describe an unusual case of a large MCC presenting as a submandibular mass without any clinically or radiologically identifiable overlying skin lesion. This report highlights the need to include MCC in the differential diagnosis of rapidly enlarging submandibular masses lacking an apparent cutaneous origin.