RESUMEN
Objective:To investigate the ultrasonographic features and evolution of thyroid shrinking nodules in order to improve the differential diagnosis and management strategy and avoid unnecessary biopsy.Methods:A total of 245 patients with old bleeding of benign thyroid nodules diagnosed via fine needle aspiration cytology (FNAC) from May 2015 to July 2020 in the southern part of the Shanghai General Hospital Affiliated to the Medical College of Shanghai Jiaotong University, including 263 nodules. The sonographic parameters such as size, shape, aspect ratio, echo, edge, boundary, periphery, halo, calcification, posterior echo enhancement and posterior acoustic attenuation of nodules were analyzed retrospectively, and the ultrasonic appearances of nodules were classified; 41 nodules from 40 patients, who did ultrasound examinations more than twice and had both complete ultrasonographic data, were compared and then classified in order to explore the evolution rules of the nodules.Results:Two hundred and sixty-three thyroid shrinking nodules in 245 cases were classified into 4 types: "cystic wall shrinkage sign" type(71.48%, 188/263), "carcinoma-like" type (22.05%, 58/263), "inflammation-like" type(3.04%, 8/263) and "undefined atypical solid nodules" type(3.42%, 9/263). Of the 41 consecutive follow-up nodules, 37 cases showed obvious cystic wall shrinkage sign, and 7 of them developed into "carcinoma-like" type and 6 cases into "inflammation-like" type.Conclusions:The ultrasonographic appearance of thyroid shrinking nodules is a dynamic process, which can be divided into 4 types: "cystic wall shrinkage sign" , "carcinoma-like" , "inflammation-like" and "undefined atypical solid nodules" types. The "cystic wall shrinkage sign" type is typical and common. The "cystic wall shrinkage sign" type can develope into the "carcinoma-like" type or the "inflammation-like" type.