[Bronchiolo-alveolar cell carcinoma of the lung presenting as spontaneous pneumothorax].

A 30-year old man visited a local clinic complaining of dyspnea and chest pain. He had a history of hepatocystadenocarcinoma 10 years before. Pneumothorax was diagnosed. Immediately, the patient was referred to us and underwent a tube thoracostomy. Cytologic examination of pleural effusion specimens revealed malignant cells. Because pleural drainage and pleurodesis using anti-cancer agents were not effective, we performed a thoracotomy. A tumor with accompanying bulla was detected in the right S6 region and a right lower lobectomy was performed. Histologic examination of tumor specimens disclosed bronchiolo-alveolar cell carcinoma. We speculated that bullae formed by tumor invasion, had burst, resulting in pneumothorax. This was a case of asynchronous double cancer in a relatively young patient, and the first report in Japan of bronchiolo-alveolar cell carcinoma presenting with spontaneous pneumothorax as an initial symptom.