Submandibular Ectopic Thyroid Gland

Abstract

Ectopic thyroid glands are generally a rare entity appearing mostly in the cervical midline (90% of the cases) and even more rarely in other anatomical sites (10%). We present the case of an ectopic submandibular thyroid gland. An 81-year-old woman was referred to our department with a history of right-sided submandibular swelling. Preoperative FNA revealed benign ectopic thyroid tissue. The patient was submitted to resection of the mass. Histological examination of the specimen confirmed the diagnosis. A substitution treatment with thyroxin was initiated postoperatively, as this was the only functional thyroid tissue. Review of the literature revealed 18 similar cases. Physicians should be aware of the possibility that a submandibular swelling could be an ectopic thyroid gland. This entity poses specific diagnostic and therapeutic difficulties. Thorough preoperative diagnostics and resection of the ectopic tissue guarantee a good outcome.

Ectopic Thyroid Presenting as a Submandibular Mass

“…A lingual location is most common, accounting for 90% of the reported cases [1,3,5,6,[8][9][10]. Other sites rarely involved are the mediastinum, lungs, porta-hepatis system, duodenum, esophagus, heart, breasts, and intra-tracheal area [1][2][3][4][5][6][7][8]. Presence of ectopic thyroid tissue in the submandibular region is extremely rare [1,3,4,[7][8][9][10].…”

“…Other sites rarely involved are the mediastinum, lungs, porta-hepatis system, duodenum, esophagus, heart, breasts, and intra-tracheal area [1][2][3][4][5][6][7][8]. Presence of ectopic thyroid tissue in the submandibular region is extremely rare [1,3,4,[7][8][9][10]. According to a recent study [8], similar cases of ectopic thyroid tissue have been reported in submandibular space.…”

“…Presence of ectopic thyroid tissue in the submandibular region is extremely rare [1,3,4,[7][8][9][10]. According to a recent study [8], similar cases of ectopic thyroid tissue have been reported in submandibular space.…”

“…Ectopic thyroid along the line of the cervical midline can be explained by non-migration or by excessive migration of thyroid tissue [1,3,6,8]. On the other hand, lateral cervical location has been related to non-fusion of lateral buds of the fourth branchial pouches during the seventh week of embryonic life [1,3,8].…”

“…In some rare cases, the lack of merging of the lateral cell clusters with the median can cause a lateral ectopic thyroid gland [1,3]; when this occurs thyroid tissue is located in the submandibular region [1,3,4,[7][8][9][10].…”