Utilization of three-dimensional computed tomography for papillary thyroid carcinoma arising in the thyroglossal duct remnant: report of a case.

This report presents a rare and interesting case of papillary thyroid carcinoma arising in a thyroglossal duct remnant (TDR) that was diagnosed by three-dimensional computed tomography (3DCT). The patient, a 61-year-old woman, presented with a painless mass in the anterior suprahyoid region that had gradually enlarged over a 2-year period. Three-dimensional CT successfully revealed the thyroglossal duct (TD) descending from the tumor to the isthmus of the thyroid. An ultrasonography-guided fine-needle aspiration biopsy of the tumor was positive for carcinoma. A total thyroidectomy was performed in addition to the Sistrunk procedure. The histological findings indicated papillary thyroid carcinoma arising in the TDR and thyroid papillary microcarcinoma in the left thyroid lobe. The patient underwent radioactive iodine ablation and thyroid suppression therapy. This is apparently the first reported case of papillary thyroid carcinoma arising in a TDR evaluated using 3DCT. Three-dimensional CT was able to clarify the relative locations of the tumor, TD, and thyroid in the present case, and visualization of the TD allowed a definitive preoperative diagnosis that would not otherwise have been possible using conventional imaging techniques. This case suggests that 3DCT may therefore play an important role in providing definitive information on patients with anterior neck masses that are difficult to diagnose.