Thyroglossal Duct Cyst Mimicking a Hygroma Colli - An Unusual Presentation.

A thyroglossal duct cyst (TGDC) is the result of incomplete degeneration of the thyroglossal duct during gestation. It is the most common type of congenital cyst of the neck, and is usually seen in children. The tumor mostly appears at the midline of the neck and generally causes no symptoms, but the mass typically moves when the patient swallows. We present the unusual case of a 50-year-old man with a large cervical mass lateralized on the right side of the neck. There was no association between swallowing and movement of the mass. Clinical examination and computed tomography (CT) suggested a lymphangioma or cystic hygroma. Surgical resection showed a large cyst of 71 x 40 x 52 mm with no attachment to the hyoid bone and no invasion in blood vessels or other surrounding tissue. Histopathological investigation led to a diagnosis of TGDC.