What Is the Best Treatment for Catamenial Pneumothorax?

We read with interest the article by Seok and Lee[1] presenting the case of a left-sided catamenial pneumothorax (CP) associated with diaphragmatic fenestrations. CP is considered a rare disease, but, as reported in a recent review, its incidence amounts to 25% of spontaneous pneumothorax in surgically treated women.[2] It is more frequently located on the right side because, supposing that endometrial cells reach the thorax from the peritoneal space, the transportation occurs by a preferential clockwise peritoneal fluid current from the pelvis along the right paracolic gutter up to the subphrenic space. Cells would implant more easily on the right diaphragmatic leaf as they are stuck there by the falciform ligament[3] and “piston effect” exerted by the liver,[4] whereas the soft and compressible viscera of the left upper quadrant cannot exert such activity.