Ultrasonographic characteristics of medullary thyroid carcinoma according to nodule size: application of the Korean Thyroid Imaging Reporting and Data System and American Thyroid Association guidelines.

Hahn, Soo Yeon; Shin, Jung Hee; Oh, Young Lyun; Park, Ko Woon

<bold>Background: </bold>Few studies have categorized ultrasound (US) findings of various sized medullary thyroid carcinomas (MTCs) according to updated guidelines.<bold>Purpose: </bold>To evaluate and compare the differences in US findings of MTC according to nodule size, using the Korean Thyroid Imaging Reporting and Data System (K-TIRADS) and American Thyroid Association (ATA) guidelines.<bold>Material and Methods: </bold>The study included 119 patients with 129 MTC nodules, which were surgically confirmed at our institution between March 1999 and September 2017. Nodules were divided into large (≥1.0 cm) and small (<1.0 cm) groups. US images were analyzed according to the K-TIRADS and ATA guidelines. The differences in US characteristics between small and large nodules were compared using Fisher's exact or Chi-square tests.<bold>Results: </bold>Of 129 MTC nodules, 84 (65.1%) were large nodules and 45 (34.9%) were small nodules. According to the nodule size, small MTC nodules were classified more commonly as high suspicion by K-TIRADS and ATA (95.6% and 93.3%, respectively) (P < 0.001), but presented neither cystic change, isoechogenicity, nor low suspicion category by K-TIRADS and ATA. In contrast, large MTC nodules showed more frequently cystic change (15.5%), isoechogenicity (16.7%), smooth margins (50%), or low or intermediate suspicion US features by K-TIRADS and ATA (59.6% and 36.0%, respectively) (all P values < 0.001).<bold>Conclusion: </bold>Most small MTC nodules are classified as high suspicion on US, whereas large MTC nodules are diagnosed more frequently as low or intermediate suspicion by K-TIRADS and ATA.

MEDULLARY thyroid carcinoma; THYROID gland; ULTRASONIC imaging; CHI-squared test; THYROID gland tumors; ANTHROPOMETRY; RETROSPECTIVE studies; MEDICAL protocols; NEUROENDOCRINE tumors

Acta Radiologica, 2021, Vol 62, Issue 4, p474

0284-1851

Academic Journal

10.1177/0284185120929699