A 46-Year-Old Man with an Incidental Finding of a Papillary Thyroid Carcinoma in a Thyroglossal Duct Cyst

BACKGROUND The thyroglossal duct cyst, which develops from the midline migratory tract between the foramen cecum and the anatomic location of the thyroid, is the most prevalent congenital abnormality of the neck, accounting for about 70% of all cervical neck masses in children and 7% in adults. Only up to 1% of these abnormalities contain malignant thyroid tissue, with 90% of those cases being papillary thyroid carcinoma. Thyroglossal duct cyst is rarely linked to carcinoma. Clinical presentation of thyroglossal duct cyst carcinoma is generally impossible to differentiate from benign tumors before surgery, and most cases are incidentally detected after surgery, due to histopathological evaluation of the resected cyst. CASE REPORT A 46-year-old man presented with a painless, progressively enlarging neck lump. Physical examination identified a well-defined, mildly firm mass situated anteroinferior to the hyoid bone. Imaging indicated that a thyroid gland duct cyst was the most likely diagnosis. The patient underwent the Sistrunk procedure. Histopathological analysis revealed papillary thyroid carcinoma within the thyroid gland duct cyst. CONCLUSIONS Carcinomas occurring in the thyroglossal cyst are uncommon. The causes of thyroglossal duct carcinoma are unclear, and neither a detailed medical history nor a physical examination can reliably diagnose it before surgery. The management of such cases remains debated, owing to the rarity of reported occurrences. So far, the standard treatment involves the Sistrunk procedure, followed by close patient monitoring. For patients with metastatic disease, a total thyroidectomy is necessary, and if neck metastases are present, neck dissection is required.