Follicular carcinoma in ectopic thyroid gland. A case report

Ectopic thyroid rest can be seen anywhere along the path of descent of the gland. The most ectopic thyroid tissue is a thyroglossal duct cyst associated with normal thyroid gland. Sublingual location is less common than a lingual ectopia. True malignant transformation in ectopic thyroid tissue is extremely rare. Such a malignancy is virtually always diagnosed only after surgical excision of the lesion at pathological examination. This report discusses a case of ectopic thyroid follicular carcinoma in the right submandibular region in the absence of orthotopic thyroid, discovered by chance after the surgical excision performed for a preoperative ultrasonically and cytologically misdiagnosed submandibular gland adenocystic carcinoma. The possible aetiology of such an unusual anatomical relationship is discussed as well as the importance of thyroid scanning, ultrasound and/or CT in neck lumps.