Endobronchial Metastasis of Renal Cancer Presented as Atelectasis

The most common primary tumors associated with endobronchial metastasis (EBM) are colorectal, breast, and renal. When EBM is present, respiratory symptoms such as shortness of breath or hemoptysis accompanied by coughing usually appear. Herein, we report a case of atelectasis caused by EBM of renal cell carcinoma (RCC) in a 53-year-old man who underwent laparoscopic radical nephrectomy for RCC 5 years ago. The patient's primary RCC stage was pT1b, and the histological cell type was clear cell RCC with Fuhrman nuclear grade 3/4. At the time of EBM diagnosis, the patient was classified as "favorable" according to IMDC (International mRCC Database Consortium) risk calculator. The patient refused surgical treatment and received targeted therapy with sunitinib. A tumor mass spontaneously detached and came out through the airway during targeted therapy. Subsequently, the patient's respiratory symptoms were alleviated, and his atelectasis disappeared. This case shows that when there is atelectasis due to EBM of RCC, the obstructed bronchus may be reopened with targeted therapy without any interventional treatment.