Dual ectopic thyroid is a rare clinical entity and few cases have been reported in literature(1-5). We herein report a case of dual ectopic thyroid with both radionuclide and computed tomography (CT) scan documentation. The present case, in addition to being an unusual one, illustrates the importance of 99mTc-pertechnetate scan in a clinically diagnosed case of ectopic thyroid and emphasizes the value of scanning the entire pathway of thyroglossal duct, which can reveal the presence of thyroid tissue in other regions, that may not be clinically apparent.

A 11-year-old girl presented with a gradually increasing anterior midline swelling. The size of the mass at the time of presentation was around 4 cm × 3 cm on palpation. It was nontender, situated at the level of thyroid cartilage and was moving freely with deglutition. Based on these findings, a diagnosis of ectopic thyroid was made. A 99mTc pertechnetate scan revealed two foci of tracer concentration in the sublingual and subhyoid regions. An ultra-sonography (USG) of neck showed a soft tissue mass (3.7 × 2.9 ×1.3 cm) anterior to right lamina of thyroid cartilage with an echotexture similar to normal thyroid gland and no thyroid gland was seen at the normal position. USG could not document the sublingual thyroid. The fine needle aspiration cytology (FNAC) of the palpable neck swelling was suggestive of chronic thyroiditis. The thyroid function tests showed a hypothyroid status with a T4 level of 4 µg/dL/1 (normal: 4.2-13.1 µg/dL) and a TSH level of >100 µIU/mL (normal: 0.25-5.1 µ/mL and antimicrosomal antibody titre was 1:402 (normal 1:102). Replacement therapy with thyroxin was instituted which resulted in symptomatic improvement and helped in reduction in the size of the swelling as a result of suppressed TSH. Because of the disparity between radionuclide scan and USG findings, a CT scan of neck was done in the first followup (after 3 months of presentation) which was in agreement with radionuclide scan finding showing two homogeneous hyperdense enhancing lesions, one in sublingual (around 1.3 cm in diameter) and another in subhyoid region. The size of the subhyoid mass (1 cm × 0.6 cm) reduced considerably in comparison to the size at the time of presentation (3.7 × 2.9 × 1.3 cm) measured by USG.

Sandip Basu*,
Narendra Nair*,
Radiation Medicine Center,
Bhabha Atomic Research Center,
Tata Memorial Hospital Annexe,
Jerbai Wadia Road, Parel,
Mumbai 400 012, India.
E-mail: [email protected]