[430] Repeat Fine Needle Aspiration Biopsy in Patients with Cytologically Atypical Thyroid Lesions

Trisha M Shattuck, Claudia K Jones. Duke University Medical Center, Durham, NC

Background: The Bethesda System for Reporting Thyroid Cytopathology includes two categories for classification of indeterminate lesions, “Atypia of Undetermined Significance” (AUS) and “Follicular Lesion of Undetermined Significance” (FLUS). The recommended follow-up for these lesions is to re-biopsy in three to six months. However, data on repeat biopsy of patients with atypical diagnoses are scant, and the best management for patients with two consecutive atypical biopsies remains unclear.
Design: A search of the PathNet clinical database was performed to identify thyroid fine needle aspiration (FNA) specimens collected between January 2009 and July 2011. The cytologic, imaging, and clinical characteristics and histologic follow-up was collected for all cases with an AUS or FLUS diagnosis.
Results: The search yielded 1177 thyroid FNA accessions. Atypical diagnoses were rendered in 125 cases from 117 patients. The ratio of atypical diagnoses to malignant diagnoses was 2.6:1. Forty-six (39%) patients underwent excision following the first atypical diagnosis while 39 patients (33%) were followed-up with a repeat biopsy performed 1 week to 13 months after the first biopsy (average 5 months). In 15 of these patients, the second biopsy was called benign. Twenty-three patients had an abnormal result on the second biopsy. Six of these were given a more definitive diagnosis, with three called diagnostic of papillary carcinoma and three called suspicious for follicular neoplasm. Seventeen of the atypical cases had a second biopsy that was also called atypical. In general, the atypical cytologic features seen in the first and second specimens (i.e microfollicular architecture, nuclear atypia) were similar. Of the fourteen double atypical cases that were excised, none were malignant. Six demonstrated follicular adenomas and remaining cases were hyperplasias or Hashimoto's thyroiditis.
Conclusions: Re-biopsy in patients with an atypical diagnosis on an initial biopsy serves to better clarify risk of malignancy. Of the patients re-biopsied in our cohort, all who had malignant lesions received a more definitive diagnosis on second biopsy. None of our patients with two consecutive atypical diagnoses had a malignancy on excision. This suggests that patients with repeat atypical results may benefit from continued clinical follow-up rather than surgery.
Category: Cytopathology

Wednesday, March 21, 2012 1:00 PM

Poster Session VI # 58, Wednesday Afternoon


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