# Pleural Metastasis From Male Breast Cancer: A Case Report

## TL;DR

This case report describes a rare instance of male breast cancer that spread to the pleura, highlighting the diagnostic value of cytology.

## Contribution

The paper presents a rare case of pleural metastasis from male breast cancer and emphasizes the utility of effusion cytology in diagnosis.

## Key findings

- The tumor cells showed positivity for multiple markers including ER, AR, PR, and ki67.
- Effusion cytology was found to be an accurate diagnostic method for metastatic carcinomas in this case.

## Abstract

Male breast cancer (MBC) is a rare disease accounting for less than 1% of breast cancers and for 0.11% of all male malignancies. Despite the fact that the epidemiologic, clinical, and therapeutic literature regarding female breast cancer is well documented, little is known about the features of male breast cancer. Here, we present a case of cytological pleural metastasis from ductal breast carcinoma in a 55‐year‐old man. Immunohistochemical staining showed that the tumor cells were positive for BerEp4, GATA‐3, AE1/AE3, CAM5.2, ER (70%), AR (10%), PR (10%), and ki67 (10%). In our experience, effusion cytology remains an accurate tool for the diagnosis of metastatic carcinomas.