Pleural solitary fibrous tumor with bullae: is it a microinvasive tumor?

We report a rare pleural solitary fibrous tumor with bullae. Chest computed tomography showed a nodular lesion with bullae adjacent to the left diaphragm. Thoracoscopic resection followed by a pathology study showed that the tumor was a solitary fibrous tumor beside the visceral pleura. We suggest that the bullae containing dilated bronchioles were caused by a check-valve mechanism next to the microinvasive component in the solitary fibrous tumor.