Papillary thyroid carcinoma in thyroglossal duct cyst: case reports and literature review.

Although thyroglossal duct cysts represent a common developmental abnormality of the thyroid gland, malignant transformation is rare and occurs in only 1% of cases. This article describes four clinical cases observed at the Surgical Science Department of "La Sapienza" University of Rome between 1996 and 2000. Histologic examination indicated two pure papillary carcinomas, a sclerosing papillary carcinoma, and a follicular variant of papillary carcinoma. In all cases, treatment involved removal of the body of the hyoid bone and total thyroidectomy, which we associated with removal of the thyroglossal duct cyst. In one case, laterocervical lymphectomy was performed. Carcinoma multifocality was found in one patient. We recommend associating total thyroidectomy with removal of the tumor of the thyroglossal duct and of the body of the hyoid bone, because the carcinoma may be multifocal and there may be lymphatic invasion of the thyroid and to ensure a correct follow-up.