Elevated carcinoembryonic antigen and bronchial obstruction caused by a rotten vegetable leaf mimic lung cancer: A case report.

Background Tracheobronchial foreign body aspiration is a potentially risky medical event, while the condition often requires early detection and rapid intervention to improve respiratory symptoms and prevent major morbidity. Notably, foreign bodies may not be identified and they are likely to be mistaken for neoplastic lesions. However, CEA, as one of tumor markers, presents to be available for assisting in lung cancer diagnosis, especially for non-small-cell lung cancer, while the specificity of CEA is not high. Methods Here, we described a case of bronchial opening obstruction with elevated carcinoembryonic antigen (CEA) that was firstly misdiagnosed as lung cancer and proved as foreign body aspiration in the upper lobe bronchus of right lung by bronchoscopy. Results Carcinoembryonic antigen level increased. CT scan demonstrated a cavitation accompanied by multiple small nodular shadows appeared in the right upper lobe field. Bronchoscopy suggested right upper lobe bronchus was blocked by a brown smooth organism with plenty of purulent materials, which was proved as a rotten vegetable leaf. Conclusions Elevated CEA and bronchial obstruction are not typical manifestations of lung cancer. Bronchoscopy is crucial for making a reliable diagnosis.