Interobserver variability with the interpretation of thyroid FNA specimens showing predominantly Hürthle cells.

Fine-needle aspiration (FNA) is used for the diagnosis and triaging of thyroid lesions. Recently, it has been shown that the pathologic interpretation of selected thyroid specimens can show a high degree of interobserver variability (IV). Because Hurthle cells may be seen in neoplastic and nonneoplastic disease, we investigated whether pathologists consistently interpret FNA specimens from these lesions. In the present study, 22 FNA specimens that showed Hurthle cells as the predominant cell type were reviewed by 7 pathologists. Cytologic features were assessed semiquantitatively. IV was calculated, and individual case diagnoses were compared with cytologic features. IV was high before diagnoses were collapsed into like diagnoses and triage recommendations (κ = 0.17, 0.44, and 0.51, respectively). Overall cellularity, number of Hurthle cells, and number of lymphocytes all correlated with collapsed diagnostic agreement, and the number of air-dried rapid Romanowsky–stained slides, overall cellularity, number of Hurthle cells, and number of lymphocytes all correlated with collapsed triage recommendations.