Metastatic Breast Cancer Presenting as an Organizing Pneumonia Pattern on Chest CT: A Case Report

TL;DR

A rare case of breast cancer spreading to the lungs and appearing like pneumonia on imaging is reported, emphasizing the need for tissue testing in similar cases.

Contribution

This case report adds to the limited literature on breast cancer metastasis mimicking organizing pneumonia on chest CT.

Findings

A 68-year-old woman with a history of breast cancer presented with lung infiltrates resembling organizing pneumonia.

Biopsy confirmed metastatic breast cancer with estrogen receptor and GATA3 positivity.

Treatment with S-1 led to radiological improvement after four months.

Abstract

Pulmonary metastasis from breast cancer typically presents as multiple well-defined nodules on chest imaging. Atypical radiological patterns, including air-space consolidation mimicking organizing pneumonia (OP), are exceedingly rare and diagnostically challenging. We report a case of a 68-year-old woman with a history of left breast cancer treated 26 years earlier who developed new bilateral bronchovascular bundle thickening with surrounding ground-glass opacities and consolidation on chest CT, mimicking OP. The patient had been receiving fulvestrant for known pulmonary metastasis diagnosed 14 years prior. A transbronchial biopsy from the left lower lobe revealed adenocarcinoma with positive immunostaining for estrogen receptor and GATA-binding protein 3, consistent with metastatic breast cancer. Treatment with S-1 resulted in radiological improvement at four months. This case adds to the limited literature documenting OP-mimicking pulmonary metastasis from breast cancer and highlights the importance of maintaining a high index of suspicion and pursuing tissue diagnosis in patients with a history of breast cancer who present with new pulmonary infiltrates.

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