Thyroid fine‐needle aspiration with atypia of undetermined significance

Abstract

BACKGROUND:Atypia of undetermined significance is a controversial category in thyroid fine‐needle aspiration (FNA), not only for its questioned clinical utility, but also for its very existence as an expression of uncertainty. The current study was performed to investigate the potential impact of eliminating this category on the sensitivity and specificity for detecting thyroid neoplasms by FNA.METHODS:Forty cases originally diagnosed as atypia of undetermined significance with histologic follow‐up were selected for the present study. These cases were reinterpreted blindly by 2 experienced reviewers, who eliminated atypia of undetermined significance as a diagnostic possibility and reclassified these cases as either benign, follicular neoplasm, suspicious for malignancy, or malignant. Twenty‐six cases of atypia of undetermined significance were randomly selected and reevaluated 6 months later to study intraobserver variation.RESULTS:After eliminating the atypia of undetermined significance category, the sensitivity for detecting papillary thyroid carcinoma (PTC) was reduced from 100% to 27% (P = .04). In those atypia of undetermined significance cases that were reclassified as benign, 37% had PTC. In those reclassified as follicular neoplasm or suspicious for malignancy, 38% were histologically proven to be benign lesions. Unanimous interobserver and intraobserver agreement was observed in only 60% of cases.CONCLUSIONS:Eliminating the diagnosis of atypia of undetermined significance substantially decreases the sensitivity of thyroid FNAs and increases both false‐positive and false‐negative rates. In addition, it increases interobserver and intraobserver variability. Therefore, the atypia of undetermined significance category should not be eliminated; but we advocate minimizing its use. Cancer (Cancer Cytopathol) 2009. © 2009 American Cancer Society.

The atypical thyroid fine‐needle aspiration: Past, present, and future

“…Layfield et al, Ohori et al, Muddegowda et al, and Shi et al have reported low reproducibility for AUS/FLUS, with marked interobserver and intraobserver variations. 15,16,30,31 The level of experience of the clinician/pathologist performing the thyroid FNA, the methods used for specimen preparation and staining, the number of FNA passes performed, and the availability of onsite rapid interpretation may all be contributing factors to this variation. The publication of reference images and text for TBSRTC, both in print and on the Internet (available at: www.papsociety.org), will inevitably promote greater uniformity.…”

“…In addition, Shi et al and Yang et al have shown that if AUS cases are forced into either lower or higher diagnostic risk categories, the latter results in diminished sensitivity for detecting thyroid neoplasms, with increased false-negative and false-positive rates, making thyroid FNA a less effective screening test. 31,47 Future Directions Although to our knowledge immunohistochemistry has only a very limited role in thyroid cytology, [48][49][50] molecular testing using markers such as BRAF, RET/PTC, RAS, and paired box gene (PAX)/peroxisome proliferator-activated receptor-c (PPAR-c) shows more promise for wider applicability. [51][52][53][54] A BRAF mutation or RET/PTC gene rearrangement has very high specificity for PTC.…”

Thyroid Fine-Needle Aspiration Reporting Rates and Outcomes Before and After Bethesda Implementation Within a Combined Academic and Community Hospital System

“…[9][10][11][12][13][14][15][16][17][18] These same studies have also reported their respective rates of malignancy as ranging from 6% to 48% for cases classified as AUS/FLUS with available followup. [9][10][11][12][14][15][16][17][18][19] It was noted at the time of the National Cancer Institute State of the Science Conference that the original recommendations may need to be revisited. Recently published data suggest that there is still some variation in incidence and risk of malignancy for the AUS/FLUS category.…”

Management and Malignancy Rate of Thyroid Nodules with a Cytologic Diagnosis of Atypia or Follicular Lesion of Undetermined Significance

“…7 But in Texas and Ohio, they reported a malignancy rate of 13 and 19% respectively. 9,10 A study in South Korea reported a malignancy rate of 47%, while an academic institution in the US reported a malignancy rate of 48%.…”