Abstract
Pneumothorax has been reported as a pazopanib-associated adverse event in patients with lung metastases of soft tissue sarcoma (STS). However, pneumothorax triggered by eribulin treatment has never been reported. We herein report two cases of spontaneous pneumothorax in patients with STS treated with eribulin. Both patients experienced pneumothorax accompanied by sudden dyspnea on day 9 or 10 of eribulin treatment. These two cases suggest that spontaneous pneumothorax may occur as an adverse event of eribulin treatment in such patients. We should therefore be alert for the potential development of pneumothorax during eribulin treatment of patients with STS and lung metastases.