Application of The International System for Reporting Serous Fluid Cytopathology (TIS) on Reporting Various Body Fluids: A Study from a Tertiary Care Hospital of Western India

Background: Serous effusion is the accumulation of fluid in body cavities due to various causes, with malignancies being one of the important contributors. The various sites from which fluid can be sent for analysis include the pleural, peritoneal, and pericardial cavities. Materials and Methods: This was a retrospective observational study. A total of 114 fluids were studied. All received body fluid samples sent to the cytopathology section of the pathology department, including pleural and peritoneal fluids, were examined, excluding sputum and broncho-alveolar lavage fluid. Wherever available, histopathological samples from the same patient were used for correlation. Results: A total of 114 fluids were studied. Histopathological correlation was available in 30 cases. Epithelial malignancy, including adenocarcinoma, was the most common malignancy involving pleural effusion and peritoneal fluid. Conclusion: The international system of reporting is a user-friendly framework that can be easily applied to effusion fluid for better patient management and effective communication with clinicians. Due to the well-documented outcomes from adopting uniform cytology terminology for other organ systems, we recommend the use of this classification and believe its use will be paramount in improving diagnostic yield in effusion cytology.