A case of endobronchial metastasis of colon cancer mimics sarcoidosis, and a review of related literature

Purpose Endobronchial metastases (EBM) are defined as bronchoscopically visible lesions histopathologically identical to extrapulmonary tumors. We summarized the literature on endobronchial metastasis of colorectal cancer and give a brief review. Method We present a rare case with an episode mistaken for sarcoidosis and unexpectedly identified as colon cancer by bronchoscopic biopsy. A 53-year-old man with dry cough and dyspnea had diffuse micro lung nodules and lymphadenopathy on CT and PET/CT. He was diagnosed with sarcoidosis and took steroid therapy, but the symptoms could not be alleviated. Bronchoscopy was suggested. He was finally identified with colon cancer by bronchoscopic biopsy, which was confirmed by endoscopic biopsy. We summarise the clinical manifestations, imaging, prognosis of EMB of colorectal cancer. Result EBM are rare. Colorectal cancer is common in EBM and the frequency is increasing. Conclusion EBM should be distinguished from primary lung cancer, sarcoidosis.