Follicular Variant of Papillary Carcinoma Arising in Thyroid Tissue Remnant of Thyroglossal Duct Cyst: A Rare Entity

Abstract

The thyroglossal duct cysts (TDC) are cystic expansions, arising from the abortive obliteration of the duct during embryogenesis. They represent the most common congenital abnormality of thyroid development, involving around 7% of the population. Malignancy arising from these cysts is extremely rare and accounts for 1% of TDC. Hereby, we report a case of a tiny midline neck swelling in a 28-year-old female, with clinical and radiological diagnosis of thyroglossal cyst. The case was referred for fine needle aspiration, where we have reported it as malignant small blue round cell tumor, thereby alerting surgeon the need for early surgical intervention. The histopathological examination revealed the presence of follicular variant of papillary carcinoma arising in the thyroid tissue remnant of thyroglossal cyst. This case report enhances the importance of cytological evaluation of cystic swellings in neck, which many times can contain foci of malignancies, especially papillary carcinomas that are known for cystic change.

Keywords

• cytology
• papillary carcinoma
• thyroglossal cyst