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Subclassification of atypical cells of undetermined significance in direct smears of fine‐needle aspirations of the thyroid
Author(s) -
Renshaw Andrew A.
Publication year - 2011
Publication title -
cancer cytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.29
H-Index - 57
eISSN - 1934-6638
pISSN - 1934-662X
DOI - 10.1002/cncy.20154
Subject(s) - medicine , atypia , malignancy , pathology , thyroid , cytology , thyroid cancer , fine needle aspiration , thyroid carcinoma , bethesda system , biopsy , radiology
BACKGROUND: Atypical cells of undetermined significance (AUS) in thyroid fine‐needle aspirates (FNAs) may have poor interobserver agreement. Some authors have suggested that “atrophic” microfollicles should be diagnosed as benign. This laboratory sought to determine whether criteria for this diagnosis could be improved by subcategorizing cases into specific patterns, including the atrophic pattern, and determining their risk of malignancy. METHODS: A series of 7089 FNAs were reviewed and correlated with subsequent resection specimens. Cases of AUS were reviewed and subclassified. RESULTS: Cases could be subcategorized into the following categories: 1) atypical, papillary carcinoma cannot be ruled out, 2) atypical, Hürthle cell neoplasm can not be ruled out, 3) cellular atrophic pattern, 4) scant atrophic pattern, and 5) cytologic atypia alone. Cytologic atypia alone (50%) and both atrophic patterns (21% and 34%) had a significant risk of malignancy. CONCLUSIONS: The majority of AUS cases in thyroid FNA can be subcategorized into 5 different patterns, all with associated significant risk of malignancy. “Atrophic” microfollicles are a significant risk factor for malignancy and should not be diagnosed as benign on the basis of lack of cytologic atypia. Cancer (Cancer Cytopathol) 2011;. © 2011 American Cancer Society.