Ectopic Thyroid Tissue in Submandibular Region

Ectopic thyroid is the presence of gland at any location except for its normal position in the anterior neck in front of the trachea. It may result from an early arrest of migration or migration along an abnormal path. Ectopic thyroid in the submandibular region is relatively unusual and may or may not be accompanied with the orthotopically located thyroid gland. Pathological changes reported in the literature in the ectopic gland include goitrous change, hyperplasia, malignancy, and, rarely, inflammation. Patients usually present as a palpable, mobile, and painless mass below the lateral jaw. The important differentials include salivary gland tumor, lymphoma, inflammatory lymphadenopathy, lipoma, and cysts. Ultrasonography, radionuclide scan, computed tomography, and magnetic resonance imaging are the diagnostic modalities for documenting the presence of ectopia. Evaluation of functional status with thyroid profile and histopathological examination after fine-needle aspiration cytology directs further management. Surgical removal is the preferred treatment for ectopic thyroid. Thyroidectomy predisposes the patient to iatrogenic hypothyroidism if eutopic thyroid is absent or hypofunctioning. Such patients require lifelong thyroid replacement. However, asymptomatic cases may be managed conservatively. Ectopic thyroid in the submandibular region has important clinical implications and hence, even though rare, should be considered as one of the differentials in the patient presenting with swelling below the lateral jaw.