Modified K-TIRADS 3 nodule with partially cystic US pattern in a 44-year-old woman.Transverse US shows a predominantly solid isoechoic nodule (40 mm) without any suspicious US features in the right thyroid lobe. This nodule is classified as intermediate-risk by the AACE/ACE/AME guideline, not suspicious (TR2) by the ACR TIRADS, very low suspicion by the ATA guideline, intermediate-risk (TIRADS 4) by the EU-TIRADS, and low suspicion (TIRADS 4) by the K-TIRADS. Final diagnosis: minimally invasive follicular thyroid carcinoma by surgery. K-TIRADS, Korean Thyroid Imaging Reporting and Data System; US, ultrasonography; AACE, American Association of Clinical Endocrinologists; ACE, American College of Endocrinology; AME, Associazione Medici Endocrinologi; ACR TI-RADS, American College of Radiology Thyroid Imaging Reporting and Data System; ATA, American Thyroid Association; EU-TIRADS, European Thyroid Imaging Reporting and Data System.