Catamenial Pneumothorax* A Prospective Study

Objectives: To evaluate the incidence of catamenial pneumothorax (CP) among women who have been referred for the surgical treatment of spontaneous pneumothorax (SP) and to study its pathogenic mechanisms. Design: A prospective study of women of reproductive age who have been referred to our center for the surgical treatment of SP. Patients with pneumothorax secondary to a known lung disease were excluded. Setting: A university hospital. Methods: At the preoperative evaluation, special attention was given to the investigation of a possible temporal relationship between pneumothorax and menses. Video-assisted thoracoscopy constituted the operative technique of choice. The lung was inspected to identify blebs or bullae and the origin of possible air leaks. Signs of thoracic endometriosis were also carefully searched for. The diaphragm was systematically inspected to search for holes and/or endometrial implants. When limited diaphragmatic abnormalities were found, a partial diaphragmatic resection was carried out using an endoscopic stapler. In case of lesions that were not accessible by a purely endoscopic approach, a utility minithoracotomy was used. Results: In an 18-month period, 32 women with SP were referred for surgery. In eight cases, the catamenial character of the pneumothorax was recognized by clinical history. In all these patients, the following diaphragmatic abnormalities were found at surgery: holes (one patient); endometrial implants (three patients); and both (four patients). Visceral pleural endometriosis was found in one patient. During pathologic examination, diaphragmatic endometriosis was confirmed in seven of the eight cases. In one patient, it was associated with pulmonary and pleural endometriosis. In only one patient (with multiple diaphragmatic holes and a pulmonary nodular brown lesion), endometriosis could not be confirmed at histology, but signs of parenchymal focal hemorrhages were found. Conclusions: Our experience shows that (1) CP is more frequent than expected and (2) diaphragmatic abnormalities seem to play a fundamental role in its pathogenesis.