Cytological analysis of thyroglossal duct cysts

Introduction. Thyroglossal duct cysts are regarded as congenital anomalies. They arise from the residual segments of thyroglossal duct. A cancer with the incidence rate from 1% to 1.5% may develop in thyroglossal duct cysts. Approximately 30% of patients asked to be examined due to inflammatory cysts. This study was aimed at determining the cytological characteristics of thyroglossal duct cyst smear, such as cell specificity, cellularity and the content of the extracellular matrix. Material and Methods. Thyroglossal duct cyst smears were analyzed in 28 adult patients who had undergone the fine-needle aspiration cytology in the period from 2004 to 2014. Three patients underwent the surgery following the Sistrunk procedure. The rest of the patients are in the process of monitoring. The monitoring process lasts from 1 to 10 years. Results. As many as 27 out of 28 smears contained macrophages, 9 contained stratified squamous epithelial cells and only 4 smears contained follicular cells. Granulocytes were present in 4 smears. Two smears had scarce cellularity, 21 had moderate and 5 high cellularity. Malignant cells were not observed. In 19 smears, extracellular matrix consisted of cholesterol crystals. Conclusion. Thyroglossal duct cysts have no specific cytological features. Macrophages are the dominant cell population. Cholesterol crystals and stratified squamous epithelial cells enable differentiation of thyroglossal duct cysts from thyroid gland cystic nodules. Fine-needle aspiration cytology is necessary when assessing the cellular composition of thyroglossal duct cysts in order to promptly detect the possible presence of malignant cells and to conduct a surgical treatment.