Intrathoracic endometriosis resulting in catamenial pneumothorax.

A woman in her early 40s presented with right-side chest pain radiating to the ipsilateral shoulder coinciding with her menstrual periods. She complained of worsening dysmenorrhoea over the preceding 6 months. Chest radiograph was notable for pneumothorax. Conservative management through hormonal suppression was initially pursued but proved ineffective for preventing recurrence. The patient ultimately underwent video-assisted diagnostic thoracoscopic surgery through robotic approach; intraoperative findings confirmed the presence of endometrial deposits of the diaphragm, confirming the cause of the patient's catamenial pneumothorax. The patient recovered well and was started on a gonadotropin-releasing hormone antagonist 3 weeks following her operation.