Incidental early lung adenocarcinoma after surgery for catamenial pneumothorax.

A 40-year-old female patient underwent surgery at our hospital for recurrent pneumothorax. A defect on the right diaphragm was diagnosed as ectopic endometriosis. However, air leakage continued 2 days after surgery. Chest computed tomography identified a 5-mm ground glass opacity in the right S3 field, suggestive of lung cancer. Ten days after the initial surgery, she underwent curative surgery for both pneumothorax and the lung tumor. The tumor was diagnosed as bronchioloalveolar carcinoma, but no other endometriosis was identified. The patient has remained well with no recurrence of lung cancer or pneumothorax since the second surgery.