Development along bronchial duct in metastasis from renal cell carcinoma detected by retrospective chest CT findings

Background: Bronchial metastases are often observed as recurrence sites of renal cell carcinoma. Periodic chest CT is available after nephrectomy, and occasionally bronchoscopy is necessary for the early detection of metastasis in the respiratory airway. Case: The patient had undergone left nephrectomy for renal cell carcinoma. Four years and 6 months later, partial resection of the left upper lobe of the lung was performed for metastasis of renal cell carcinoma. A chest CT at 6 years and 3 months after the nephrectomy revealed a 40 mm tumor in the right lower lobe of the lung. Bronchoscopy findings showed a polypoid tumor (right, B¹⁰), and subsequent brushing cytology suggested primary lung squamous cell carcinoma. A right lung lower lobectomy was performed, and the pathological diagnosis was metastasis from renal cell carcinoma. Retrospective chest CT findings revealed a tiny abnormal lesion at the segmental bronchus (right, B¹⁰) at 1 year and 6 months before right lung lower lobectomy. Conclusion: In the follow-up chest CT for early detection of respiratory airway metastasis from renal cell carcinoma, peripheral non-tumorous bronchial change is important in the detection of endobronchial metastasis.