Ultrasound characteristics of medullary thyroid carcinoma and prognostic significance

Purpose: To investigate the ultrasound characteristics of medullary thyroid carcinoma and their relationship with prognosis. Materials and methods: A retrospective analysis was conducted on 133 medullary thyroid carcinoma nodules, encompassing their ultrasound findings and relevant clinical data. Based on the ultrasound characteristics, medullary thyroid carcinoma nodules were categorised into a benign feature group or malignant feature group, followed by a comparative assessment of disparities in ultrasound features and prognostic indicators between these two groups. Results: Among the 133 medullary thyroid carcinoma nodules analysed, there were 92 cases of malignant feature group (69.2%) and 41 cases of benign feature group (30.8%). The ultrasound characteristics of the benign feature group included well-defined borders (65.9%), hypo echogenicity (87.8%), rich blood flow (48.8%) or abundant blood flow (31.7%), and the absence of calcification (51.2%), or the presence of coarse calcification (36.6%). In contrast, the ultrasound characteristics of the malignant feature group revealed indistinct borders in the majority of cases (96.7%), hypoechogenicity in most cases (82.6%) or very low echogenicity in some cases (16.3%), and relatively rich blood flow in a significant number out of 92 patients (78.3%), with coarse calcification present in 66 cases (71.7%). Compared to the benign feature group, the malignant feature group demonstrated significantly higher rates of lymph node metastasis (69.6% vs 12.2%), distant metastasis (28.3% vs 9.8%), and recurrence (41.3% vs 9.8%). Moreover, the malignant feature group exhibited elevated preoperative calcitonin levels and its ultrasound features were found to be atypical in comparison with the benign feature group. A comprehensive understanding of the ultrasound characteristics of the benign feature group holds substantial clinical significance for diagnosing suspicious cases of medullary thyroid carcinoma. Furthermore, the ultrasound features of medullary thyroid carcinoma can serve as prognostic indicators, with the benign feature group having a more favorable prognosis than the malignant feature group. Conclusion: Medullary thyroid carcinoma demonstrates two distinct sonographic patterns. The benign feature group, often exhibiting benign-appearing features, is associated with a significantly more favorable prognosis than the malignant feature group. Recognising the benign feature group pattern is crucial to avoid misdiagnosis, and preoperative ultrasound features serve as valuable prognostic indicators.