Papillary adenocarcinoma of a thyroglossal duct cyst.

A rare case of papillary adenocarcinoma arising in a thyroglossal duct cyst is reported. A 37-year-old man developed a mass in the anterior neck which had increased in size in the past two months. A well circumscribed and firm mass was palpated in the midline of the neck at the level of the hyoid bone. A thyroid scintigram showed normal uptake and normal location of the thyroid gland. The clinical diagnosis was thyroglossal duct cyst. The mass was removed by Sistrunk's procedure. Histological examination showed a thyroglossal duct cyst with local involvement of malignant cells, suggesting papillary adenocarcinoma arising in the thyroglossal duct cyst. The patient's postoperative course has been unremarkable for 13 months. The clinical and pathological features are reviewed, and the method of diagnosis is discussed.