The "Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance (AUS/FLUS)" category in the Bethesda System for Reporting Thyroid Cytology is heterogeneous and includes both specimens with borderline cellularity/compromised quality and those with genuine atypia. We have used a reporting scheme that is similar to the Bethesda System but does not include an AUS/FLUS category. We retrospectively reviewed all reports on thyroid FNA and thyroidectomy specimens submitted to the Beth Israel Deaconess Medical Center from January 2006 to December 2008. The positive predictive values for various categories and subcategories in this scheme demonstrate that the AUS/FLUS category can be eliminated to provide information for the most appropriate management of patients with thyroid nodules.

The 3 classical UOC cell types are identifiable on FNA, making cytologic diagnosis possible if considered in the differential. A PDAC component is often also observed. The survival advantage of UOC over pure PDAC appears to be negated by FNA and requires further investigation. Cancer Cytopathol 2017;125:563-75. © 2017 American Cancer Society.

Objective: The Bethesda System for reporting thyroid fine-needle aspirations (FNAs) recommends repeat aspirations be done at least 3 months following the initial aspiration to prevent false-positive misinterpretations due to reactive/reparative changes. Because limited data exists, we reviewed our own data to ascertain the recommendation. Study Design: We retrospectively reviewed thyroid FNAs accessioned in the Cytology Laboratory at Beth Israel Deaconess Medical Center in Boston, Mass., USA, from January 2006 to December 2008. We identified patients with repeat aspirates of a single lesion and those with thyroidectomy specimens. Cytologic and surgical diagnoses along with time between FNAs were recorded. Results: No statistically significant difference was detected in the distribution among nondiagnostic, suboptimal, and adequate categories with respect to the timing of repeat FNA (p = 0.25). Forty-six percent of the lesions that were nondiagnostic/suboptimal initially yielded the same results on repeat. Twenty-eight percent of initially adequate specimens were nondiagnostic/suboptimal on repeat (p = 0.04). Nine percent of those with an initial atypical diagnosis had the same diagnosis on repeat, while 2.6% of those who did not have an initial atypical diagnosis had an atypical diagnosis on repeat (p = 0.29). False positives between early (16%) and late (12%) repeats were not statistically significant (p = 0.74). Conclusion: The diagnostic yield and accuracy of repeat FNA is independent of the time interval between procedures but may be related to the original FNA diagnosis.

The AUS category has a PPV approaching 50% in our lab. This creates uncertainty regarding the appropriate management for this category and may cause unnecessary overuse of molecular testing for cases in the AUS category.

No abstract