Mutations of RAS genes in benign lesions included HRAS G13R mutation found in one follicular adenoma with uncertain behavior and in one solitary thyroid nodule with oncocytic changes, KRAS G12D mutation in the multinodular goiter, KRAS Q61R mutation in the follicular adenoma and NRAS Q61R mutation in the multinodular goiter with oncocytic changes. This evidence concerns the gene KRAS and multinodular goiter.