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.