Lateral dermoid cyst of the floor of mouth: unusual radiologic and pathologic findings.

A lateral dermoid cyst is a rare lesion of the floor of mouth, with only 12 cases reported in the literature. We describe the case of a 60-year-old man with a slowly enlarging mass in the submandibular region. Magnetic resonance imaging demonstrated a lesion containing multiple uniformly rounded foci, creating a "sack-of-marbles" appearance. Needle aspirations showed atypical findings, and the mass was excised. Histopathology revealed a cyst containing a keratinizing stratified squamous epithelial lining with apocrine and eccrine glands. These findings were diagnostic of a dermoid cyst, which should be considered in the differential diagnosis of any midline or lateral cervical lesion.