[Thyroid papillary carcinoma arising in a thyroglossal cyst. Therapeutic treatment].

Cysts of the thyroglossal duct form the congenital, not odontogenetic, more frequent malformations of neck and head pathology. In percentage terms one percent developed a carcinoma, usually of good prognosis. This paper reports the case of a woman, 41, who was operated upon of a thyroglossal duct cyst and in the eradicated piece showed a papillary carcinoma invading neighbouring tissues. Treatment was completed, in a second time, with a complete thyroidectomy and a the papillary carcinoma was discovered. Some interesting aspects regarding diagnosis and treatment of this scarce entity are reviewed.