Significance of sonographic characterization for managing subcentimeter thyroid nodules

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.

To evaluate the diagnostic accuracy of malignant sonographic features of subcentimeter thyroid nodules.

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.

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.

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.