Pyopneumothorax during bevacizumab-containing chemotherapy in a patient with metastatic breast cancer

Pyopneumothorax is a rare but troubling complication of bevacizumab. We herein report a case of pyopneumothorax in a patient with metastatic breast cancer during bevacizumab treatment. A 60-year-old female who was diagnosed with metastatic breast cancer (ER+ , PgR+ , HER2-, Ki67 <14 %, metastasized to lung, pleural, brain, subcutaneous tissue, and bone) was started on bevacizumab plus paclitaxel chemotherapy. Although the disease was well-controlled, pyopneumothorax was noted after 3 months of treatment and the chemotherapy was therefore stopped immediately. The pyopneumothorax was so intractable that no conservative treatment could successfully manage it. The patient underwent a radical operation using the technique of latissimus dorsi muscle transfer. The operation improved her general condition and lead to hormonal therapy. Our case indicates the successful management of a severe side effect of bevacizumab for a breast cancer patient.