Endobronchial metastasis secondary to occulting renal cell carcinoma: literature review and a rare case report

BACKGROUND: Endobronchial Metastasis from extrathoracic tumors is a rare neoplasm that accounts for approximately 1.1% of total endobronchial malignancies. The most common primary tumors associated with EBM are from the colorectal, breast, and kidney regions. Although it represents a late manifestation in the context of tumor progression, it can rarely antedate the diagnosis of the primary tumor. CASE PRESENTATION: A 67-years-old male was referred from another city hospital to our thoracic surgery department due to a 4-months history of hemoptysis and productive cough. A chest X-ray and computed tomography scan showed a soft-tissue mass within the left main bronchus and atelectasis of the anterior segment of the left upper lobe. Furthermore, a flexible bronchoscopy revealed a hypervascular lesion occluding completely the left upper lobe bronchus. The patient underwent lobectomy and pathological examination suggested endobronchial metastasis from clear cell renal cell carcinoma. A second computed tomography scan of the abdomen and pelvis showed a well-defined mass arising from the lateral aspect of the right kidney; therefore, the patient underwent right radical nephrectomy three weeks later and pathology confirmed the diagnosis of clear renal cell carcinoma with endobronchial metastasis. CONCLUSION: Despite its rarity, physicians should consider the possibility of endobronchial metastases in the setting of endobronchial lesions. Proper diagnostic approaches should also be considered to rule out the potential of asymptomatic extrathoracic neoplasms. In this manuscript, we aimed to report a rare case -the first from Syria to our knowledge- of an endobronchial metastasis that preceded the diagnosis of renal cell carcinoma. Importantly, we reviewed the existing literature and discussed the diagnostic and treatment approaches.