Application of the international system for reporting serous fluid cytopathology on reporting various body fluids; experience of a tertiary care hospital.

Objectives: Cytological examination of effusion sample is a preliminary and minimally invasive method for the diagnosis of body fluids. Recently, the International System For Reporting Serous Fluid Cytopathology (ISRSFC) and the Indian Academy of Cytologist (IAC) have published guidelines for reporting effusion cytology and calculating the risks of malignancy (ROMs) for each defined category. We report our 2 years of experience in reclassifying and assessing the feasibility of applying ISRFSC and IAC categories to effusion fluid and to provide an estimate of the risk of malignancy for each diagnostic category. Material and Methods: Cytological reports of patients from January 2019 to December 2020 were retrieved and reclassified into a five-tiered classification scheme as per ISRSFC guidelines. Cellblock and immunohistochemistry were performed in selected cases. Clinico radiological and histopathological information were obtained and correlated with the cytological findings wherever available. Results: In the study, 652 cases were included during the 2 years. Out of these, 328 (50.3%) were women and 314 (47.3%) were men. Patient's ages ranged between 2 92 years with a mean age of 47.4 years. There were 366 (56.1%) cases of ascitic fluid followed by 262 (40.1%) cases of pleural fluid and 24 (3.8%) cases of pericardial fluid in the analysis. Of all the cases, 13 (2%) were non-diagnostic (ND), 464 (71.6%) were negative for malignant (NFM) cells, 16 (2.4%) were atypia of uncertain significance, 31 (4.7%) were suspicious of malignancy, and 125 (19.3%) were malignant. Cellblock was prepared in 65 cases. Lung cancer followed by breast cancer was the most common malignancies involving the pleural effusion and ovarian cancer was the most common cause of peritoneal effusion. ROM for each diagnostic category was 23% for ND, 25% for NFM, 56% for the atypical category, 80.6% in suspicious, and 90% were for positive for malignancy category. Conclusion: The use of a five-tiered system as per the ISRFC and IAC guidelines are feasible for the standardized reporting of effusion samples, thus avoiding subjective variation of reporting.