PAPILLARY THYROID CARCINOMA CONFINED TO A THYROGLOSSAL DUCT CYST: A CASE REPORT

Abstract

Introduction: Papillary thyroid carcinoma (PTC) is the most common malignant histological subtype reported within a thyroglossal duct cyst (TGDC), with malignant transformation occurring in approximately 1% of cases. In this case, a 42-year-old man presented with a six-month history of a gradually enlarging midline anterior neck mass. Clinical findings: Examination revealed a smooth, non-tender mass at the level of the hyoid bone that moved with swallowing and tongue protrusion. Imaging demonstrated a mixed cystic-solid mass with internal calcifications and no evidence of local invasion or cervical lymphadenopathy. Fine-needle aspiration was non diagnostic. Main diagnosis: Following Sistrunk surgery, histopathological examination demonstrated papillary thyroid carcinoma confined to the cyst wall, with no extension into surrounding tissues or lymphovascular invasion. Postoperative thyroid ultrasonography showed no suspicious thyroid lesion, and thyroid function tests were within normal limits. Conclusion: This case demonstrates the rare occurrence of PTC arising within a TGDC and highlights the importance of complete surgical excision and careful histopathological assessment, even when clinical findings are not overtly suggestive of malignancy.