[Papillary thyroid carcinoma in a median ectopic thyroid associated with intra-abdominal thyroid tissue].

A 17-year-old female underwent surgical removal of a painless submental lump presumed to be a median cervical cyst. Histology showed a papillary thyroid carcinoma with invasion of the surrounding connective tissue. A 99m-technetium scan, performed in preparation for a planned total thyroidectomy, demonstrated no thyroid tissue. On subsequent 123-iodine scanning there was an area of increased uptake about 3 cm above the larynx, but no normal thyroid tissue. Histological sections, obtained during further surgical exploration of the base of the tongue, showed scattered thyroid cell rests in the lingual muscles. Whole-body scanning, carried out in connection with administration of radioiodine for ablation of remaining thyroid tissue, disclosed an unexpected area of increased uptake in the epigastrium. Sonography and CT scans failed to demonstrate any corresponding morphological abnormality. Following a further dose of radioiodine 4 months later, no areas of increased uptake were noted.