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Cytotechnologist performance for screening microfollicular atypia in indeterminate thyroid fine-needle aspirates
Christopher J VandenBussche1, Matthew T Olson, Christina Adams
1Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Md., USA.
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 one-category 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.
