An Interesting Case of Thyrotoxicosis.

Ectopic thyroid tissue can be present in the embryonal path of descent of the thyroglossal duct anywhere from the foramen caecum to the thyroid gland. However, for such ectopic thyroid tissue to be hyperfunctioning is quite rare. Here, we discuss a 56-year-old female patient who presented with persistent thyrotoxicosis for over 7 years. She had undergone thyroidectomy in 1982 for thyrotoxicosis and was rendered hypothyroid (thyroid-stimulating hormone of 75 μIU/mL). Whole-body technetium scan was done twice which did not show any uptake in the neck or other parts of the body and an empirical dose of 15 mCi of radioiodine therapy was also given to treat the thyrotoxicosis. She continued to be thyrotoxic and was on carbimazole 30 mg/day along with beta-blockers. In 2021, an Iodine131 whole-body scan revealed small remnant thyroid tissue and an ectopic thyroid tissue in a thyroglossal cyst. In such cases of persistent or recurrent thyrotoxicosis despite standard treatments, an ectopic location should be sought after and treated.