Role of clinicopathologic and sonographic characteristics for the management of patients with cytological diagnosis of thyroid follicular neoplasm.

[BACKGROUND] Thyroid cancer is one of the most common endocrine tumors and preoperative diagnosis of thyroid follicular neoplasm (FN) is challenging. Commonly used examination methods have difficulty in distinguishing thyroid cancer from other follicular lesions. At the same time, with the recently released World Health Organization (WHO) guidelines, the risk classification of FNs of the thyroid is a new enlightenment for clinicians in the diagnosis and treatment. Therefore, we conducted this study to help identify malignant tumors, determine the appropriate extent of surgery, and reduce unnecessary surgical resection.

[METHODS] We performed this retrospective cohort study between January 2015 and December 2023. According to the inclusion and exclusion criteria, 192 patients were finally included for subsequent analysis. Clinical and pathological characteristics, examination test results, and surgical information were collected to explore factors that aid decision making. Categorical variables were compared using Pearson's Chi-squared test or Fisher's exact-test and continuous variables were analyzed using the Mann-Whitney -test. Ordinal logistic regression was carried out to appraise the relative risks of malignancy.

[RESULTS] There were 192 patients included and analyzed in this study. Significant differences were observed between the three groups regarding tumor size, interval to surgery, nodule components, and several sonographic features. Ordinal logistic regression analysis demonstrated that taller than wide [odds ratio (OR) =3.219], irregular margins (OR =4.118), hypoechogenicity (OR =2.134) and calcifications (OR =2.144) were independent risk factors for malignancy. Furthermore, noteworthy case series, such as patients with incidentally discovered papillary microcarcinoma and postoperative pathologically confirmed follicular thyroid carcinoma were also documented.

[CONCLUSIONS] Patients with a cytological diagnosis of FN with ultrasound features of taller than wide, irregular margins, hypoechogenicity, and calcifications might be at high risk for malignancy and should be treated with caution. In the future, a multi-factor risk assessment diagnostic prediction model should be established and applied.