Secondary pneumothorax in a patient with pulmonary metastasis of myxofibrosarcoma during the administration of pazopanib

Abstract

Background. Pazopanib is a multitargeted tyrosine kinase inhibitor. Frequent adverse events caused by pazopanib include hypertension, fatigue, nausea, diarrhea, weight loss and liver toxicity. Pneumothorax was reported in a clinical trial of treatment with pazopanib for soft tissue sarcoma; however, this complication has not been reported in detail and its relevance for treatment is unclear. Case. A 73-year-old male with pulmonary metastasis of myxofibrosarcoma originating in the left chest wall underwent systemic chemotherapy with doxorubicin. The pulmonary metastatic lesions were progressive; therefore, treatment with pazopanib (800 mg daily) was initiated. Ten days later, the patient experienced right chest pain and dyspnea. A chest roentgenogram revealed right tension pneumothorax, and chest drainage was performed. Chest computed tomography (CT) showed multiple nodules in the bilateral lungs that were slightly smaller than those observed before the administration of pazopanib. Moreover, the lesion in the right upper lobe was found to be a cavity with a thin wall compared with that observed in the previous CT findings. Massive air leakage was observed, a surgery was performed. The location of the air leak was identified to be the lesion of pulmonary metastasis that had been found to be a cavity in the right upper lobe. Thoracoscopic partial pulmonary resection including the lesion was performed. Pathologically, the specimen was confirmed to be pulmonary metastasis of high-grade myxofibrosarcoma. Microscopically, invasion of tumor cells to the visceral pleura, exposure of tumor cells to the pleural cavity and collapse of the visceral pleura were detected. We speculated that the pneumothorax observed in our patient was likely an adverse event of the treatment with pazopanib. Conclusions. It is necessary to pay attention to the development of pneumothorax when prescribing pazopanib in patients with pulmonary metastasis. © 2013 The Japan Lung Cancer Society.