Axitinib Induced Recurrent Pneumothorax following Near-Complete Response of Renal Cell Carcinoma Lung Metastasis: An Unexpected Complication

We report a case of a Caucasian male with a history of renal cell carcinoma metastatic (mRCC) to the lungs refractory despite aggressive treatment with several lines of targeted therapy. He was started on axitinib palliative targeted therapy with a good clinical and radiological response; however one month after treatment initiation he presented to the emergency department with severe dyspnea and hypoxemia. Physical exam and chest X-ray revealed left-sided tension pneumothorax which required emergent thoracostomy with subsequent improvement; however it recurred requiring video assisted thoracoscopy. A left-sided 4 × 3 cm cavitated necrotic lesion was found at the level of the main pulmonary artery. Repair with pericardial fat flap was performed. Surgical biopsies from this lesion revealed mRCC with extensive necrosis. Imaging studies before and after axitinib use showed an initial 4 × 3 cm mass seen in the same location of this large cavitated necrotic tumor. Pneumothorax has not been described as a potential major complication from the use of axitinib. Complete or near-complete responses of mRCC to axitinib targeted therapy may lead to this potential life-threatening complication, particularly if the metastatic lesions are located near to pleural structures. We also review pertinent clinical trial data on axitinib.