Abstract
A 38-year-old woman was referred to our hospital because of pneumothorax related to menstruation. Thoracoscopy on the 22nd day of the menstrual cycle revealed the presence of diffuse, brown lesions in the visceral and parietal pleurae in the left thoracic cavity. Histopathological findings of visceral and parietal pleurae did not contradict endometriosis. On the 3rd postoperative day, she was diagnosed as having right pneumothorax just after menstruation and was treated with a chest tube. Postoperatively she has been symptom free for a year on hormonal therapy. We examined thoracic endometriosis before shedding, because thoracoscopy was performed just before menstruation. The physiological mechanism of this case was suspected to be that the endometriotic tissue invaded from the abdominal cavity to the left thoracic cavity. The endometriotic tissue was implanted in the visceral pleura and sloughed in synchrony with the menstrual cycle. Endometriosis in the parietal pleura is very rare. When we consider the physiological mechanism of catamenial pneumothorax, this case is very interesting and valuable.
