Significance of repeatedly nondiagnostic thyroid fine-needle aspirations

Nondiagnostic thyroid fine-needle aspirations are associated with a risk of malignancy that can be reduced with repeated aspiration. However, the significance of repeated nondiagnostic aspirates is less well studied. This study assessed the risk of malignancy for repeated nondiagnostic aspirates from a large series of cases using the results of histologic follow-up. From a series of 7,089 aspirates, there were 1,671 nondiagnostic aspirates (23.6%), and 235 of these (14.1%) had histologic follow-up. The risk of malignancy for a single nondiagnostic aspirate was 20.0% (47/235). A total of 51 cases had repeated aspiration. The risk of malignancy for cases with a second nondiagnostic aspirate was 0% (0/23), which was significantly less than for patients with a single nondiagnostic aspirate (20.0%; P = .03). Patients with 2 sequential nondiagnostic thyroid aspirates have a very low risk of malignancy. Cytologists should strive to better convey this risk in their reports.