Thyroglossal duct cyst presents most frequently in the midline of the neck, either at or just below the level of the hyoid bone. We describe a thyroglossal duct cyst appeared on the left submandibular region in a 28-year-old woman. The mass was located in the left submandibular region, above the level of the hyoid bone. This mass moved in a vertical fashion on swallowing. CT and MRI examination revealed a cystic structure extending to the left submandibular region from the base of the tongue. The cystic lesion was removed surgically with the patient under general anesthesia. Histopathological analysis revealed a cyst with a dense fibrotic wall; there was no epithelial cell lining, but many ductal structures consisted of single epithelial cell layer were observed in the cyst wall. The clinical and histopathological findings suggested that the lesion was a thyroglossal duct cyst. There was no evidence of recurrence 4 months after surgery.
