A case of papillary carcinoma in a thyroglossal cyst without a carcinoma in the thyroid gland.

The thyroglossal duct cyst is the most common developmental anomaly of the thyroid gland. We present a patient with a papillary thyroid carcinoma diagnosed after surgical resection of a thyroglossal cyst. The 39-year-old patient reported to our hospital due to a swelling of this throat. The results of the ultrasonography were reported as showing multiple nodules in both thyroid lobes, and an ~3-cm diameter image in the submental area, in keeping with lymphadenomegalia. In the fine-needle aspiration cytology (FNAC) evaluation from the nodules in the thyroid, it was observed that the thyrocites with uniform nuclei made up single-layer groups. FNAC from the thyroglossal cyst, a few histiocytes were observed on a ground with a large number of erythrocytes. The patient was subjected to a total thyroidectomy, pyramidal lobe excision, and total excision of the 3-cm diameter soft mass, starting at the tip of the pyramidal lobe. The case was diagnosed as papillary thyroid carcinoma in thyroglossal duct cyst with histopathological and immunohistochemical findings. If the thyroglossal channel cyst had been diagnosed preoperatively, total thyroidectomy and a Sistrunk operation would have been performed. For this reason, repeated FNAC, particularly, if performed under ultrasound guidance, may improve the diagnostic value of FNAC. Thus, in such patients, throat ultrasonography must be carried out in expert hands, thin-needle aspiration biopsy, computerized tomography, and thyroid scintigraphy must be done if necessary, and the necessary treatment protocols carried out after a definite diagnosis.