Endocrine Abstracts

JOINT703

Introduction: Medullary thyroid carcinoma (MTC) is a rare thyroid malignancy with distinct histological characteristics, making its diagnosis via conventional ultrasound (US) challenging. Although malignancy risk stratification benefits from features like hypoechogenicity, irregular margins, and microcalcifications, their specificity for MTC remains under debate. This study evaluates the potential of combining elastographic stiffness measurements with US features to improve diagnostic accuracy in MTC.

Materials and Methods: This study analyzed 20 histopathologically confirmed MTC cases. Conventional US was used to assess nodule features indicative of malignancy, including hypoechogenicity, inhomogeneity, a taller-than-wide shape, irregular margins, microcalcifications, an interrupted thyroid capsule, and suspicious cervical lymphadenopathy. Shear Wave Elastography (SWE) (Aixplorer Mach 30) quantified nodule stiffness, with a mean elasticity index (EI) cut-off of 30 kPa used to suggest malignancy.

Results: The median patient age was 53.5 years, with a female predominance (70%, 14/20). The median nodule volume was 0.55 ml. All nodules were solid and hypoechoic, with 80% (16/20) showing inhomogeneous echotexture. Seven nodules had a taller-than-wide shape, and eight demonstrated irregular margins. No cases showed an interrupted capsule, while suspicious lymph nodes were detected in three cases on US. Microcalcifications were noted in 35% (7/20) of nodules, and 60% (12/20) were classified as high-risk according to TIRADS. SWE revealed increased stiffness in 75% (15/20) of nodules. The median EI was 35.5 kPa, with a maximum of 58.8 kPa. Coexisting autoimmune thyroiditis was present in 40% (8/20) of patients.

Conclusions: Integrating elastographic stiffness measurements with conventional US features enhances the diagnostic precision for MTC. SWE, in particular, serves as a reliable, non-invasive adjunct in differentiating malignant from benign thyroid nodules, emphasizing its clinical utility in routine practice.

Keywords: medullary thyroid carcinoma, ultrasound, elastography, shear wave elastography, diagnostic imaging.