Thyroglossal duct cysts: variability of sonographic findings

The purpose of this study was to describe the sonographic features of thyroglossal duct cysts, emphasizing the variable sonographic appearances, and determine if the presence of infection or inflammation influences the sonographic appearance.

We reviewed the sonograms in 12 children (2 months-16 years old) with pathologically proven thyroglossal duct cysts (TDCs). The cysts were evaluated for location, size, cystic versus solid features, echogenicity, and wall thickness. The sonographic features then were compared with the pathologic findings.

Sonograms of the 12 lesions showed that nine were midline at or near hyoid bone; two were to the right of midline in the submandibular region; and one was located to the left of midline in the neck. Cysts were from 0.5 cm to 4 cm in diameter. Five lesions were anechoic with no perceptible wall thickness. Seven lesions were hypoechoic. Two of the seven were homogeneously hypoechoic with thin borders. The remaining five lesions were hypoechoic but heterogeneous (complex). One lesion was hypoechoic with small anechoic spaces. Four lesions were largely cystic with dense internal echoes and thick walls. The presence of thick walls and internal echoes did not correlate with the presence or absence of inflammation on pathologic examination. No lesions in our series were hyperechoic.

Our results indicate that TDCs have a variable sonographic appearance. Anechoic, homogeneously hypoechoic, and heterogeneous (complex) lesions occur. We found no correlation between the pathologic findings of infection and inflammation and the sonographic appearance of TDCs. Awareness of the variable sonographic appearance of the TDC is helpful when a midline lesion is encountered in the neck.