A Case of an Ectopic Cyst of the Salivary Gland: One of the Causes of Median Cervical Cyst (Thyroglossal Duct Cyst) Recurrences

Abstract

We report a patient with an ectopic cyst of the salivary gland, and where an etiological factor for multiple recurrent median cervical cysts could be histopathologically verified.
The patient was a 5-year-old boy. At the age of 2 years, a cystic region measuring about 5 mm in diameter was noted in the right mandibule. He was referred to our hospital because the cystic region had enlarged over the last few months. Detailed examination led to diagnosis of an ectopic cyst of the mucous gland which was then scheduled for resection. During surgery, mucus elimination from the cyst was confirmed. Furthermore, a cordlike substance connecting the cyst to the median anterior surface of the hyoid bone was observed. These findings suggested an ectopic mucous cyst was connected to the thyroglossal duct, and for which cystectomy and Sistrunk's operation were performed.
Histopathologically, cordlike connective tissue, involving the cyst to median hyoid bone, and a duct in the connective tissue were noted. The duct partially showed atrophy, and an occlusive site was present. However, it was connected to the thyroglossal duct of the median hyoid bone.
Based on these findings, the patient was diagnosed with ectopic salivary gland cyst draining into the thyroglossal duct cyst.
The present case may provide information/data useful for understanding the etiology of multiple recurrent thyroglossal duct cyst.