<![CDATA[Introduction: Breast cancer often metastasizes to bone, liver, and lungs, while endobronchial metastasis (EBM) is rare, accounting for only 2–28% of cases and is exceptionally uncommon when bilateral. Case Presentation: We report a 37-year-old woman with stage IV breast cancer who developed bilateral endobronchial metastasis (EBM) within three months after completing chemoradiotherapy. She later presented with progressive dyspnea, hemoptysis, and chest pain. Chest radiography revealed bilateral pleural effusion and right lung collapse. Bronchoscopy demonstrated total obstruction (100%) of the right main bronchus and approximately 80% obstruction of the left, with nodular intraluminal masses. Histopathology revealed malignant round-to-oval cells with a high nuclear-to-cytoplasmic ratio. Immunohistochemistry showed ER positivity and TTF-1 negativity, confirming metastatic breast carcinoma. Despite systemic therapy and supportive care, her condition rapidly deteriorated, and she died from respiratory failure. Conclusion: Bilateral endobronchial metastasis from breast cancer is an extremely rare and fatal manifestation. Awareness of this condition is crucial, as it may mimic other pulmonary complications. Early bronchoscopy should be considered in advanced breast cancer patients with compatible clinical and radiological findings to allow timely diagnosis, appropriate management, and improved symptom control. This case highlights the importance of maintaining a high index of suspicion for endobronchial metastasis in patients presenting with unexplained respiratory symptoms.]]>
