Fine Needle Aspiration Acta Cytologica 2014;58:432–438 DOI: 10.1159/000367882

Received: July 4, 2014 Accepted after revision: August 25, 2014 Published online: October 17, 2014

Cytotechnologist Performance for Screening Microfollicular Atypia in Indeterminate Thyroid Fine-Needle Aspirates Christopher J. VandenBussche a Matthew T. Olson a Christina Adams a Syed Z. Ali a, b Departments of a Pathology and b Radiology, The Johns Hopkins University School of Medicine, Baltimore, Md., USA

Abstract Introduction: We previously identified a high level of accuracy among our cytotechnologists (CTs) for identifying nuclear atypia in thyroid fine-needle aspiration (FNA) specimens. Herewith, we present our CT performance at screening for microfollicular atypia. Methods: 8,814 thyroid FNA specimens were identified in our archives, all screened by 1 of 11 CTs and signed out by a cytopathologist. A subsample of cases was categorized either as atypia of uncertain significance (AUS) with microfollicular proliferation (AUS-F) or suspicious for a follicular neoplasm (SFN). Results: The agreement rate was low between CTs and cytopathologists for SFN and AUS-F. Only 55.8% of SFN screening diagnoses were upheld; 27.9% were downgraded to AUS, 10.4% were downgraded to benign, and 5% were upgraded. Of AUS-F screening diagnoses, 35.5% were upheld, 33.7% were downgraded to benign, and 20.2% were upgraded to SFN. Among all cases, two-step discrepancies were uncommon. Conclusion: Most disagreements were onecategory discrepancies between AUS-F and SFN. The evaluation of microfollicular atypia is challenging given that certain follicular lesions cannot be definitively diagnosed on cytology, a high level of subjectivity is involved in the interpretation of such lesions, and the presence of nuclear or Hurthle cell atypia may complicate the diagnosis. © 2014 S. Karger AG, Basel

© 2014 S. Karger AG, Basel 0001–5547/14/0585–0432$39.50/0 E-Mail [email protected] www.karger.com/acy

Introduction

The relative decline in Pap test volumes has uncovered the need to demonstrate roles for cytotechnologists (CTs) in the cytopathology workflow beyond Pap test screening. For instance, CTs have demonstrated usefulness in the performance of on-site evaluation of adequacy (OSEA; also known as Rapid On-site Evaluation or ROSE) [1–4], the screening of nongynecological specimens [5] and interfacing cytopathology with molecular methods [6]. Concurrently, thyroid fine-needle aspirations (FNA) have more than septupled at our institution over the past decade [3] and are becoming the most common nongynecological specimens in most cytopathology laboratories. Because of this increased volume, CTs are a vital component in the diagnostic process for thyroid FNA specimens during OSEA, screening and the management of ancillary (molecular) testing. While quality performance measures for evaluating an individual’s skill at interpreting Pap tests [7–9] are well defined given established regulatory practices, performance measures for nongynecological specimens are not well established. Thus, we have examined our institutional practice in an attempt to begin the development of new performance measures for these new roles. One of the challenges in deriving performance metrics for thyroid FNA screening is the complexity of thyroid FNA specimens compared to Pap test specimens. Thyroid FNA specimens often involve multiple slides, the incorpoCorrespondence to: Dr. Christopher J. VandenBussche Pathology 406, The Johns Hopkins Hospital 600 North Wolfe Street Baltimore, MD 21287 (USA) E-Mail cjvand @ jhmi.edu

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Key Words Thyroid · Fine-needle aspiration · Atypia · Microfollicular · Cytotechnologist · Screening

ration of multiple morphological findings into a single diagnosis, a larger number of primary tumor types, and the need to assign one category from a six-tiered Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) [10] as opposed to a three-category Bethesda System for Reporting Cervical Cytology [11]. Additionally, the subjectivity of morphological diagnosis is as well known in thyroid cytopathology [12] as it is for gynecological cytopathology [13]. To simplify this problem, we have focused on the spectrum of diagnoses that involve ‘microfollicular atypia’ in thyroid FNA. We have previously shown that specimens diagnosed as atypia of uncertain significance (AUS) and containing microfollicular atypia (AUS-F) have a 27% chance of being malignant, which is significantly higher than the 12% chance of malignancy attributable to AUS from nonnuclear and nonmicrofollicular AUS subtypes [14]. While these cases do not contain the same quantity of microfollicles that is necessary to make the diagnosis of suspicious for a follicular neoplasm (SFN) [15], the risk appears sufficiently high to warrant identifying these patients for additional management. Because microfollicular atypia may present as rare, scattered microfollicles present over a large number of slides in an otherwise scant specimen, the identification of microfollicular atypia by CTs during screening can improve cytopathologist efficiency and may prevent diagnostic errors due to the oversight of focal findings. Thus, the value of identifying microfollicular atypia during screening is an important skill and one that should be evaluated with straightforward metrics. Herein, we examine our institutional CT performance at screening for microfollicular atypia in thyroid FNA specimens.

Table 1. Demographics of patients with specimens diagnosed as SFN or AUS secondary to AUS-F, as rendered by a CT or cytopathologist (MD)

CT Nodules, n 522 Patients, n 488 Mean age, years 53.1 ± 15 AUS-F, n 282 (54.0) Mean smears, n 10 ± 4 Females, n 371 (71.1) Hashimoto thyroiditis, n 64 Size, cm 2.46 ± 1.5

MD

p

500 469 52.7 ± 16 205 (41.0) 11 ± 4 330 (66.0) 49 2.44 ± 1.4

0.73 0.00004 0.08 0.06 0.24 0.92

Values in parentheses are % of total.

screened per specimen, nodule size, patient age and sex, and the number of smears per nodule. A Perl script automated this process, and each case underwent a manual inspection in a Filemakerbased graphical user interface (FileMaker Inc., Santa Clara, Calif., USA) that allowed for the correction of any errors, such as typographical irregularities, made by the automated analysis. Nodule sizes were obtained from the pathology report when they were recorded. When they were not recorded in the pathology report, the size was obtained from the ultrasound-guidance procedure note or radiologic report. Differences in categorical variables were tested with the χ2 test or Fisher’s exact test if one of the counts was

Cytotechnologist performance for screening microfollicular atypia in indeterminate thyroid fine-needle aspirates.

We previously identified a high level of accuracy among our cytotechnologists (CTs) for identifying nuclear atypia in thyroid fine-needle aspiration (...
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