[Three cases of primary lung cancer unexpectedly discovered during the operation of pneumothorax]

It is well known that emphysematous bulla is thought to be often associated with lung cancer. However, it is very rare that lung cancer predisposing to pneumothorax as initial manifestation. We performed surgical operations of four hundred and one cases of spontaneous pneumothorax, and discovered three cases of lung cancer during the operation. However, these three cases occupied the 30% of the patients with pneumothorax who were older than 65 years. The two of them were adenocarcinomas which were situated in the wall of bullae, but did not perforated the bullous wall. The other one was squamous cell carcinoma which was apart from the bullous lesion. This shows that we should always be careful of the associated lung cancer when we care elderly patients with pneumothorax.