Thyroid Fine-needle Aspiration: Histologic Correlation of the Diagnostic Categories of the Bethesda System with Emphasis on “Atypia of Undetermined Significance”: A 5-year Single-institution Experience

JOURNAL TITLE: World Journal of Endocrine Surgery

Author
1. Yousef Alalawi
2. Laila M Moharram
ISSN
0975-5039
DOI
10.5005/jp-journals-10002-1274
Volume
11
Issue
3
Publishing Year
2019
Pages
4
Author Affiliations
    1. Department of Pathology, King Salman Military Hospital, Tabuk, Kingdom of Saudi Arabia
    1. Department of Surgery, King Salman Military Hospital, Tabuk, Kingdom of Saudi Arabia
  • Article keywords
    Atypia of undetermined significance, Fine-needle aspiration, The Bethesda system for reporting thyroid cytopathology

    Abstract

    Aim: The aim of this study is to correlate the thyroid cytology diagnosis with the final histologic diagnosis, which is considered by us as the gold standard diagnostic test. Materials and methods: We studied all the thyroid cytopathology cases performed over the last 5 years at King Salman Military Hospital. We found a total of 1,048 thyroid fine-needle aspiration (FNA) cases, of which 318 cases had a follow-up histologic data. The cases are reported according to the Bethesda system for reporting thyroid cytopathology (BSRTC). The rate of malignancy is calculated for each diagnostic category (DC) as the proportion of malignant cases from the cases with histologic diagnosis. The false-positive cases are defined as the cases diagnosed in FNA as DC V or VI (suspicious for malignancy or malignant) and the following thyroid surgery showed a benign histology. The false-negative cases are those diagnosed in FNA as DC II (benign) and the following thyroid surgery showed a malignant diagnosis. Results: The percentage of false-positive cases for DC V (suspicious for malignancy) is 22.5%, while it is 2.38% for DC VI (malignant). The false-negative cases are those diagnosed in FNA as DC II (benign) and the following thyroid surgery showed a malignant diagnosis (8.7%). However, after reviewing the false-negative cases, eight cases were reclassified retrospectively, as “nondiagnostic”. The malignancy rate for our “atypia of undetermined significance (AUS)” cases is estimated to be between 21% and 35%.

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