# Cytopathological evaluation of pericardial effusions: 192 cases from a tertiary-level healthcare center

## TL;DR

This study analyzed 192 pericardial effusion cases to determine the causes, finding that most were benign, but malignant cases were often linked to cancer metastases, especially lung and breast cancers.

## Contribution

The study provides a detailed cytopathological analysis of pericardial effusions and highlights sex-specific differences in malignant causes.

## Key findings

- Most pericardial effusions were non-diagnostic or benign, often due to cardiac disease or surgery.
- Lung and breast cancer metastases were the most common causes of malignant pericardial effusions.
- Cytological evaluation showed high sensitivity and specificity for detecting malignant effusions.

## Abstract

There are many different benign and malignant etiologies of pericardial effusions (PEs), which can compress the heart and large vessels emerging from the heart and cause significant clinical findings. The aim of this study was to cytologically examine the underlying diseases causing PEs and to conduct detailed evaluations of underlying cancers in cases of malignant PE, both within the whole study population and according to sex.

All PE samples obtained between 2019 and 2024 were reevaluated and categorized as nondiagnostic, negative for malignancy (NFM), atypia of undetermined significance (AUS), suspicious for malignancy (SFM), or malignant according to the 2020 International System for Serous Fluid Cytopathology.

A total of 192 PE samples from 184 patients were analyzed, with 137 categorized as NFM (71.4%), 6 as AUS (3.1%), 5 as SFM (2.6%), and 44 as malignant (22.9%). In the NFM group, PE most often developed secondary to cardiac diseases or cardiac operations (61/137, 44.5%). In the malignant group, pulmonary carcinoma metastasis was most common within the whole population (54.5%) followed by breast carcinoma metastasis (15.9%). Lung carcinoma metastasis (69%) was most common among male patients, followed by gastric carcinoma metastasis (23%), and breast carcinoma (38.9%) followed by lung carcinoma metastasis (33.3%) were most common among female patients as the causes of malignant PE. Among patients who were followed for malignancy, malignant PE was found in 64.2% (43/67). In this study, PE had sensitivity of 95.7%, specificity of 100%, positive predictive value of 100%, negative predictive value of 98.5%, and accuracy of 98.9%.

When PE develops in patients being followed for malignancy, there is an extremely high possibility of malignant PE secondary to pericardial metastasis. Cytological evaluation of PE, which has extremely high sensitivity and specificity, is of clinical importance in patient diagnosis and follow-up.