Thoracic endometriosis (TE) is a rare disorder affecting women during their reproductive years. The etiopathogenesis of this disease is not well understood; the prevailing opinion is based on analysis obtained from case reports and small case series. A 1996 review of TE was not able to address the association between clinical presentation and thoracic pathology due to a paucity of thoracoscopic findings in these earlier cases. Since the year 2001, most published cases and series have included thoracoscopic findings. Therefore, we compiled data from case reports and case series published in English from January 2001 to July 2007 to analyze the demographics, clinical characteristics, and thoracoscopic findings, and to study the relationship between thoracoscopic findings and clinical presentation in patients with thoracic endometriosis. The clinical presentations in 110 patients were as follows: pneumothorax in 79 (72%), hemoptysis in 16 (14%), hemothorax in 13 (12%), and lung mass in 2 (2%). Ninety-one of the 110 (85%) patients underwent thoracotomy or thoracoscopy. The right hemithorax was more often affected (85%) than the left side (p = 0.008). The mean (standard deviation [SD]) age of all patients was 34 (7.6 yr). The mean age of patients presenting with hemoptysis (25.9 +/- 4.6 yr) was significantly lower than the age of those presenting with pneumothorax and hemothorax (p < 0.01). There was no significant association between the presence of diaphragmatic defects and pneumothorax (odds ratio [OR], 0.3; 95% confidence interval [CI], 0.05-1.58; p = 0.23). The presence of parietal and visceral pleural implants was associated with a fivefold increase in hemothorax (OR, 5.55; 95% CI, 1.20-25.53; p < 0.01).Hemoptysis occurring in younger subjects may be the earliest manifestation of parenchymal lung involvement in TE. Diaphragmatic defects do not increase the risk for pneumothorax. Hemothorax reflects an increased burden of pleural implants in TE.