Imaging-Cytology Correlation of Thyroid Nodules with Initially Benign Cytology

Abstract EN

Objective.

To determine the role of imaging-cytology correlation in reducing false negative results of fine-needle aspiration (FNA) at thyroid nodules.

Methods.

This retrospective study included 667 nodules 1 cm or larger in 649 patients diagnosed as benign at initial cytologic evaluation and that underwent follow-up ultrasound (US) or FNA following a radiologist’s opinion on concordance between imaging and cytologic results.

We compared the risk of malignancy of nodules classified into subgroups according to the initial US features and imaging-cytology correlation.

Results.

Among included nodules, 11 nodules were proven to be malignant (1.6%) in follow-up FNA or surgery.

The malignancy rate was higher in nodules with suspicious US features (11.4%) than in nodules without suspicious US features (0.5%, P<0.001).

When a thyroid nodule had discordant US findings on image review after having benign FNA results, malignancy rate increased to 23.3%, significantly higher than that of nodules with suspicious US features (P<0.001).

However, no significant difference was found in the risk of malignancy between the nodules without suspicious US features (0.5%) and imaging-cytology concordant nodules (0.6%, P=0.438).

Conclusions.

Repeat FNA can be effectively limited to patients with cytologically benign thyroid nodules showing discordance in imaging-cytology correlation after initial biopsy, which reduces unnecessary repeat aspirations.