[400] Comparison of Ultrasound-Guided FNA with CNB in the Evaluation of Thyroid Nodules.

Katsiaryna Laziuk, William Malone, Angela Watt, Timothy A Jennings. Albany Medical College, NY; Saratoga Hospital, NY

Background: Studies comparing the diagnostic efficacy of core needle biopsy (CNB) with fine needle aspiration (FNA) of the thyroid are relatively few and have shown conflicting results.
Design: Diagnostic results from 95 cases of concurrent US-guided FNA and CNB of thyroid nodules were retrospectively evaluated. Both procedures were performed in an outpatient setting by one radiologist, utilizing 20 gauge needles for FNA, followed by CNB using Temno 20 gauge core needles with direct US guidance. All cases were interpreted by one pathologist with an interest in thyroid disease using standard diagnostic criteria, accepting that adenomatoid changes may be seen in part within cellular hyperplastic nodules. The cytological results were categorized as nondiagnostic, benign, indeterminate/abnormal, or positive, and the interpretations of the CNB were subsequently similarly categorized. The diagnostic accuracy for both techniques was assessed within the specific categories, utilizing Pearson's Chi-square test.
Results: For FNA, 24 cases were nondiagnostic, 60 were benign, 6 indeterminate/atypical, and 5 cases were positive (all papillary carcinoma). For CNB, 29 cases were nondiagnostic, 50 were benign, 13 indeterminate/atypical, and 3 positive (all papillary carcinoma). Identical diagnoses by both methods were achieved in 48/95 cases to include: 36 benign, 3 positive, 9 nondiagnostic. CNB was diagnostic in 64 cases (67%), and FNA in 65 cases (68%). Sufficient material for diagnosis from at least one technique was provided in 86 cases (91%). In our study, all 5 carcinomas were diagnosed on FNA, with only 3 of these called on CNB. Discordant cases included 4 in which the FNA was benign and the CNB indeterminate, suggesting that adenomatoid hyperplastic nodules lesions are more difficult to diagnose accurately on CNB, possibly due to a more limited sample. Comparing both techniques, FNA was significantly better at establishing a definitive diagnosis than CNB in this study (P< 0.0001).
Conclusions: Overall diagnostic sensitivity for CNB and FNA was similar in this study with an improved diagnostic rate with both techniques combined. However, FNA remains a significantly better technique for specific categorization of thyroid nodules. Furthermore, CNB offers no additional diagnostic value in distinguishing cellular (adenomatoid) hyperplastic nodules from true follicular neoplasms. Although this may be due to the more limited nature of the sample provided by CNB, this also emphasizes the need for more clearly defined criteria for diagnoses in thyroid CNB.
Category: Cytopathology

Monday, February 28, 2011 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 49, Monday Morning


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