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.

Despite the fact that CP has been known for five decades, its cause has not been defined. Thoracic endometriosis is frequently indicated as an implicated factor; however, the pathogenesis and mechanism that lead from thoracic endometriosis to pneumothorax are still unclear.

In our surgical experience with CP, we have found patients with different abnormal findings. In fact, we treated patients with endometrial foci on parietal and diaphragmatic pleura without fenestrations on diaphragm, patients with fenestrations but without any pleural endometrial foci, and patients with pleural blebs. These findings suggest that there are different kinds of CP related to different and sometimes concomitant etiologies.[5] Therefore, we agree with Seok and Lee[1] about the thesis of a multifactorial model.

Concerning CP treatment, the authors performed only surgical resection of the abnormal diaphragmatic lesions and excluded medical treatments because no endometrial foci were found on the diaphragm. However, this could be due to surgery not performed during menses.

In our opinion, surgical treatment should comprise, assessing each time, blebs resection and/or diaphragmatic repair and/or endometrial foci coagulation, depending on the abnormal findings at thoracoscopy. However, we think that, regardless of thoracoscopic findings, mechanical pleurodesis should always be performed because pleurodesis is the most important factor to avoid pneumothorax relapse.

We also think that medical treatment with gonadotropin-releasing hormone agonist should always be administered for 6 months after surgery, despite its temporary collateral effects.[2] This strategy allows to control endometriosis and reduces the risk of a new pneumothorax until pleurodesis is obtained.

Summarizing, in case of CP we prefer to combine surgical and medical treatment. We always perform thoracoscopic pleurodesis associated with the repair of every diaphragmatic, pleural, or parenchymal abnormal findings. Then, a temporary hormonal treatment is undertaken to achieve an effective pleurodesis.

• References

• 1 Seok Y, Lee E. Left-sided catamenial pneumothorax associated with diaphragmatic fenestrations. Thorac Cardiovasc Surg 2012; (e-pub ahead of print). DOI: 10.1055/s-00032-1328925.
• 2 Alifano M, Roth T, Broët SC, Schussler O, Magdeleinat P, Regnard JF. Catamenial pneumothorax: a prospective study. Chest 2003; 124 (3) 1004-1008
• 3 Vercellini P, Abbiati A, Viganò P , et al. Asymmetry in distribution of diaphragmatic endometriotic lesions: evidence in favour of the menstrual reflux theory. Hum Reprod 2007; 22 (9) 2359-2367
• 4 Kirschner PA. Porous diaphragm syndromes. Chest Surg Clin N Am 1998; 8 (2) 449-472
• 5 Baisi A, Raveglia F, De Simone M, Calati AM, Leporati A, Cioffi U. Endometriosis-related pneumothorax after in vitro fertilization embryo transfer procedure: a case report. J Thorac Cardiovasc Surg 2010; 139 (4) e88-e89