Background: Ultrasonography (US) is increasingly able to detect thyroid nodules, and the differentiation between malignant and benign nodules has been raising issues among both clinicians and patients, especially patients with non-palpable small nodules. It is important to diagnose thyroid cancer at an early stage, because it may reduce the risk of disease recurrence and possible mortality.
Purpose: To evaluate the diagnostic accuracy of malignant sonographic features of subcentimeter thyroid nodules.
Material and methods: This study examined 815 subcentimeter thyroid nodules in 815 patients. A final diagnosis was determined using fine-needle aspiration biopsy (FNAB) or postoperative pathologic findings. Logistic regression tests were used to evaluate statistical relationships between US findings and thyroid carcinoma.
Results: Of 534 lesions that showed suspicious US findings, 472 (88.4%) revealed malignancy upon cytopathology. Two hundred eighty-one lesions showed probably benign findings on US, and only 23 (8.2%) were malignant. Sensitivity, specificity, positive predictive value, and negative predictive value of US were 95.4%, 80.6%, 88.4%, and 91.8%, respectively. There was a significant difference between the two US groups in the percentages of malignancy, according to logistic regression analysis.
Conclusion: Our results demonstrate that this system of US classification can efficiently differentiate malignant subcentimeter nodules from benign nodules. Suspicious sonographic features can be useful criteria to decide whether a nodule should receive FNAB.