# Application of the Indian Academy of Cytologists’ Recommendations for Reporting Serous Fluid Cytology

## TL;DR

This study applies a five-tier reporting system for serous fluid cytology to improve communication between clinicians and pathologists and reduce reporting variability.

## Contribution

The study validates the practicality of the Indian Academy of Cytologists' five-tier reporting system for serous effusion samples.

## Key findings

- Category II was the most common classification for both pleural and peritoneal fluids.
- Category V had the highest risk of malignancy, followed by IV, III, I, and II.
- Immunocytochemical analysis showed CEA positivity in several fluid samples.

## Abstract

Background: Cytological evaluation is often the first line of investigation in the clinical setting of serous effusions. Reporting according to risk stratification can aid in a better understanding between clinicians and pathologists and the triage of patients.

Materials and methods: All serous effusion samples were collected and reported according to the guidelines of the Indian Academy of Cytologists. The risk of malignancy for each category was assessed, and immunological typing for atypical cases was performed.

Results: A total of 364 fluid samples from different age groups ranging from nine to 82 years were examined, of which 206/364 (56.5%) were pleural fluid and 158/364 (43.5%) were peritoneal fluid samples. The majority of fluids belonged to category II in both pleural (137/206, 66.5%) and peritoneal fluids (113/137, 71.5%), whereas only 9/206 (3.5%) of pleural fluid and 8/133 (5.1%) of peritoneal fluid samples were malignant. The maximum risk of malignancy was assessed for category V, followed by categories IV, III, I, and II. Immunocytochemical analysis showed cytokeratin (CK) positivity in two pleural fluid samples, whereas carcinoembryonic antigen (CEA) positivity was observed in seven pleural and eight peritoneal fluid samples.

Conclusion: The Indian Academy of Cytologists' recommendations for reporting effusion cytology utilize a five-tiered reporting system that is feasible and mitigates subjective variation in reporting.