Thyroid nodules graded 4B are completely possible to be benign, it does not mean that grade 4B is malignant. thyroid ultrasound is divided into 4A, 4B and 4C on grade 4 grading of thyroid nodules. grade 4A has a possibility of cancer or carcinoma <5%, grade 4B has a possibility of carcinoma between 5%-50%, basically 50%-50% or more, there is a possibility of benign, grade 4C has a possibility of carcinoma between 50%-95%. Usually, thyroid nodules with ultrasound grade 4B are still very likely to be benign, not necessarily malignant. Further follow-up examinations are needed to observe changes in the nodules after 3 or 6 months, and then further determine whether they are benign or malignant according to the changes.