Postirradiation carcinoma in a thyroglossal duct remnant: follicular variant of papillary thyroid carcinoma.

A case of carcinoma in a thyroglossal duct remnant is presented. The tumor was a rare follicular variant of the papillary type of thyroid carcinoma. The patient had received external beam radiation to the head and neck both as a child and as an adolescent. The recently reported increased incidence of thyroid carcinoma is believed to be related to the former practice of irradiating cervical thymic and lymphoid tissue in children. Since it is normal thyroid tissue that remains in the thyroglossal duct tract, this ectopic tissue presumably has the same malignant potential as that in the thyroid gland. Therefore, more cases of carcinoma in a thyroglossal duct remnant may be seen as those patients who underwent head and neck irradiation in childhood mature.