The Benefits of a Repeat FNA in Follicular Lesion of Undetermined Significance (FLUS) Cases
Sreelakshmi Ravula, Amanda Zopfi Conklin, Po Chu Fung, Sharon L Hirschowitz, Peggy S Sullivan. UCLA David Geffen School of Medicine, Los Angeles, CA
Background: Fine needle aspiration (FNA) is an important screening tool in the work-up of thyroid nodules. The management recommended by The Bethesda System for Reporting Thyroid Cytopathology (TBS) for a FLUS diagnosis is repeat FNA. As studies are limited, we sought to determine the benefit of a repeat FNA and the rate of malignancy in repeat FLUS cases.
Design: Retrospective review of all thyroid FNAs performed at UCLA Medical Center from 2003-2007 was performed. Cases that had a previous history of thyroidectomy or diagnosis of thyroid cancer were eliminated. Cases were re-reviewed and classified based on TBS. All cases categorized into FLUS were examined. Prior or subsequent repeat FNAs and surgical resection follow-up results were recorded for each nodule. Malignancy rates were calculated based on 1) excision and FNA diagnosis and 2) excision alone, and reported as a range between both rates.
Results: Of 2,972 thyroid FNA cases, 104 (3%) were classified as FLUS. The overall malignancy rate for all FLUS cases was 19-43%. 29 of 104 cases had a prior and/or repeat FNA. Malignancy rates did not differ significantly between repeat FLUS and non-repeat FLUS cases (17-56% and 20-41%, respectively). Prior and subsequent repeat FNA diagnoses are shown in Table 1. A repeat FNA reclassified 10 of 15 (67%) FLUS cases into a diagnostic category with definitive management, including 8 (53%) subsequent benign diagnoses (Table 1). Because case numbers were low, all prior/repeat FNAs were treated equally and combined for malignancy rate analysis (Table 2). Three of 4 FLUS+FLUS cases were malignant on excision.
|Diagnostic category||Prior FNA||Repeat FNA|
|(Suspicious for) follicular neoplasm||0||0|
|Suspicious for malignancy||0||1|
|Repeat FNA Diagnosis||Total # of cases||# Excised||# Malignant||Malignancy rate|
|FLUS+suspicious for malignancy||1||1||0||-|
|FLUS + malignant||1||1||1||100%|