[420] 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.

TABLE 1: FLUS cases with prior/repeat FNA
Diagnostic categoryPrior FNARepeat FNA
Non-diagnostic10
Benign88
FLUS95
(Suspicious for) follicular neoplasm00
Suspicious for malignancy01
Malignant01




TABLE 2: Malignancy rate for FLUS cases with repeat FNA
Repeat FNA DiagnosisTotal # of cases# Excised# MalignantMalignancy rate
FLUS+ Non-diagnostic100-
FLUS+ Benign1331*8-33%
FLUS+ FLUS134323-75%
FLUS+suspicious for malignancy110-
FLUS + malignant111100%
* - Benign FNA with a subsequent repeat FNA diagnosis of FLUS


Conclusions: Because of the high malignancy rate in FLUS+FLUS thyroid FNAs, these patients should undergo surgical excision. A repeat FNA may be beneficial because a majority of these cases are placed into a TBS category with definitive management. Further studies, including a cost-benefit analysis comparing repeat FNA with surgical excision for single FLUS cases, may be warranted.
Category: Cytopathology

Wednesday, March 21, 2012 1:00 PM

Poster Session VI # 52, Wednesday Afternoon

 

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