Giant epidermoid cyst of the floor of mouth masquerading as a foregut duplication cyst: a case report and review of the literature.

Epidermoid cysts are benign lesions composed of an epithelial lining filled with keratinous debris. The absence of skin appendages distinguishes them from true dermoid cysts. While they may occur in various anatomical locations, they rarely exceed the 5-cm threshold used to define 'giant' lesions. We report a unique case of a giant epidermoid cyst arising from the floor of the mouth, reaching a maximum diameter of 10 cm and initially mimicking a foregut duplication cyst on imaging. We describe its clinical presentation, radiological evaluation, surgical management, and histopathological diagnosis, alongside a review of the current literature.