Submandibular Ectopic Thyroid Tissue Presenting as a Neck Mass: Case Report and Literature Review

Background: Ectopic thyroid tissue is a rare developmental anomaly, typically occurring along the thyroglossal tract. Submandibular localization is extremely uncommon and poses diagnostic challenges. Case Presentation: We report the case of a 16-year-old girl presenting with a right submandibular mass. Clinical examination and imaging revealed a well-defined lesion suspicious for ectopic thyroid tissue. Investigations and Treatment: Neck ultrasound and MRI identified a complex lesion in the submandibular region. Thyroid scintigraphy confirmed ectopic thyroid tissue with absent uptake in the thyroid bed. Core biopsy demonstrated benign thyroid follicles. The patient underwent surgical excision of the lesion. Outcome and Follow-up: Postoperative follow-up showed satisfactory recovery with no recurrence. Thyroid function tests remained within normal range. Conclusion: This case emphasizes the need to include ectopic thyroid in the differential diagnosis of submandibular masses, with multimodal imaging playing a pivotal role in accurate diagnosis and guiding management.