Application of Indian Academy of cytologists guidelines for reporting serous effusions: An institutional experience

Background: Recently, the Indian Academy of Cytologists (IAC) has published the guidelines for interpretation and reporting of serous effusions. Till date, there are no studies on its applicability. Aims: The present study was carried out to assess the feasibility of applying the IAC reporting categories to effusions, determine the frequency, and provide an estimate of the risk of malignancy (ROM) for individual diagnostic categories. Materials and Methods: All cases of serous effusion fluids reported in the year 2019 were retrieved from the archives and reassigned as per the IAC diagnostic categories. The clinical and histopathological follow-up information was obtained wherever possible. Results: A total of 1340 effusion samples were received from 1085 patients. There were 561 (51.7%) males and 524 (48.3%) females. Majority were pleural (1066, 79.5%), followed by peritoneal (187, 14%) and pericardial (87, 6.5%) effusions. The age ranged from 7 months to 92 years. There were 35 (2.6%) samples in category 1 (non-diagnostic), 954 (71.2%) in category 2 (benign), 17 (1.3%) in category 3 (atypical), 59 (4.4%) in category 4 (suspicious for malignancy) and 275 (20.5%) in category 5 (malignant). The estimated ROM in serous effusion samples was 20% for category 1, 16.7% for category 2, 50% for category 3, 94.4% for category 4 and 100% for category 5. Conclusions: The categorization of serous effusion cytology samples as per the IAC diagnostic categories and as per the reporting format developed by the IAC is feasible and the management recommendations are mostly appropriate.