SONOGRAPHIC SIGNATURES OF THYROGLOSSAL DUCT CYSTS: DIAGNOSTIC ACCURACY AND CLINICAL RELEVANCE – A SYSTEMATIC REVIEW

Abstract

Background: In the last ten years, ultrasound has become a useful instrument in medical diagnostic especially in the examination of thyroid and parotid gland abnormalities. Nevertheless, the use thereof in the assessment of general head and neck conditions has not been sufficiently explored in literature. Ultrasound is particularly helpful in detecting cystic lesions as a first-line imaging tool. Ultrasound has a great potential to be used more widely in the head and neck assessments due to its non-invasive character, availability, and diagnostic accuracy. Objective: To evaluate the effectiveness of ultrasound in the diagnosis of thyroglossal duct cysts by assessing its ability to identify the nature of the lesion, the size and location of the lesion, and differentiate it from other neck masses. Methodology: Published reports of investigating the effectiveness of ultrasonography as the first line imaging modality for the diagnosis of TGDC were identified by a systematic search of Google Scholar, PubMed, ResearchGate and the Sci Hub, supplemented with citation tracking.  From 602 initially identified studies, only 21 studies met the inclusion criteria after screening and duplicate removal. These studies assessed the role of ultrasonography in early detection and diagnosis of TGDC using standard statistical measures, typically at a 95% confidence level. Results: The literature podcasts the high diagnostic accuracy and clinical utility of ultrasound in the assessment of thyroglossal duct cysts (TGDCs). On sonography, TGDCs usually appear as well defined, anechoic or hypoechoic cystic masses, frequently in the midline or para midline of the neck, and commonly attached to the hyoid bone. The sophisticated ultrasonographic findings can show heterogeneous internal echogenicity, multiloculated compartments, ill-defined or irregular margins, and longitudinal extension to the base of the tongue-findings that help to distinguish between TGDCs and dermoid cysts, lymphatic malformation, or infected lymph nodes. In others, ultrasound may reveal intralesional debris or infection or intramuscular extension, particularly in recurrent or complicated cases. The incidental detection rate of TGDCs is reported to be about 0.9 percent and stable lesions appear to change minimally over time, demonstrating the sensitivity of the modality, both in symptomatic and asymptomatic presentations. Moreover, ultrasound possesses a great level of reliability in preoperative evaluation, which would help determine the procedure of Sistrunk and reduce the possibility of recurrence. The ultrasound offers radiation-free, cost-effective, first-line diagnostic modality compared to other imaging techniques, particularly in children and young adult populations. Such a powerful sonographic nature highlights the use of ultrasound in not only the primary diagnosis but also long-term monitoring and treatment planning of TGDCs. Conclusion: The use of ultrasound has become a very sensitive, non-invasive, and accurate mode of imaging in the diagnosis and treatment of thyroglossal duct cysts (TGDCs). Its sensitivity in the precise description of the lesion morphology, evaluation of anatomic relations, and specificity in differentiation of TGDCs with the other midline neck lesions qualifies it as an essential first-line modality, especially in children and young adults. The identification of sonographic appearance of multilocation, bone attachment of the hyoid and heterogeneous echogenicity have role in increasing the confidence of the diagnosis and directing the appropriate clinical management with regard to surgery. Considering its low cost, non-exposure to radiation, and diagnostic accuracy, ultrasonography must remain the preferred initial imaging modality in the short-term follow-up and long-term monitoring of TGDCs.