Long-term outcomes of cytologically benign thyroid tumors: a retrospective analysis of 3,102 patients at a single institution

Abstract
Some thyroid tumors that are cytologically diagnosed as benign may be pathologically diagnosed as malignant. Here, we investigated the long-term outcomes of patients with thyroid tumors with benign cytology, and the factors for malignancy. We retrospectively reviewed the cases of 3,102 patients with thyroid tumors 0.01). Among the tumors of the 667 patients who were followed without surgery for >10 years, 89.9% remained unchanged and 7.2% were reduced in size. Ultrasonographic evaluation provides important information for therapeutic decision-making regarding surgery versus observation for cytologically benign tumors.