A Study of Reproducibility of Papanicolaou Society of Cytopathology System of Reporting Respiratory Cytology-A Single Institutional Experience on Image Guided Aspiration Cytology

Background: Cytologic examination of specimens obtained from the respiratory tract is a primary and frequently the initial diagnostic technique performed in patients with pulmonary abnormalities. Fine needle aspiration (FNA) is extensively used for diagnosis of pulmonary lesions. The Papanicolaou Society of Cytopathology (PSC) issued a new classification for respiratory cytology and criteria, risk of malignancy, post-cytologic diagnosis management and follow-up. Methods: Respiratory FNA specimens obtained between January 2015 to March 2021 were reviewed and reclassified according to PSC guidelines. Cytologic category as per PSC system was assigned after reviewing by two pathologists. Risk of malignancy for each category was calculated for cases where biopsy was available for correlation. Results: Three eighty-four samples were classified as non-diagnostic (30.5%), negative for malignancy (13.3%), atypical (0.5%), neoplastic (benign/ low malignant potential) (0%), suspicious for malignancy (5.7%%) and malignancy (50%). Risk of malignancy for malignant category (Category V and Category VI) was 64.1% and for non-malignant (Category I to Category IV) cases was 35.9%. Overall, there was lesser incidence of atypical category and more specific diagnoses were possible on cytology in non-malignant category. Sensitivity and specificity for malignant cases was 99.33% and 100% respectively. Conclusion: Our study substantiates that use of PSC guidelines improves the overall reporting of respiratory cytology due to the use of standardized terminology.