A 33‐year‐old woman with chest pain

A 33-year-old woman presented to the emergency department with right-sided chest pain that was worse around her menstrual periods and when she lay on her right side. She denied shortness of breath, fever, chest trauma, abdominal cramping, or a history of endometriosis. On physical examination she had diminished right-sided breath sounds with increased fremitus and egophony. A chest X-ray and computed tomography (CT) chest were obtained (Figure 1 and Figure 2). Catamenial hemopneumothorax. This is a rare cause of recurrent spontaneous pneumothorax that occurs in women of reproductive age without known respiratory disease, usually and within 72 hours of the menstrual period, and may be associated with thoracic endometriosis.1 Most cases occur on the right and may occasionally have a concomitant hemothorax.2, 3 The diagnosis is clinical but may be confirmed with video-assisted surgery. Treatment involves hormone therapy and surgery, which may include chemical or mechanical pleurodesis, wedge resection, pleurectomy, or diaphragm reconstruction. The patient's chest X-ray showed a right apical pneumothorax. A chest CT (Figure 1 and Figure 2) demonstrated the pneumothorax and a right pleural effusion. The patient was admitted and underwent video-assisted thoracoscopy that revealed multiple hemorrhage mediastinal and diaphragmatic cysts and a hemorrhagic pleural effusion, consistent with a diagnosis of catamenial hemopneumothorax. Chemical pleurodesis was performed and surgical specimens were sent to pathology with no findings of endometriosis. She was discharged on hospital day 8. Three months later, the patient had a diagnostic laparoscopy because of pelvic pain and dysmenorrhea. She was diagnosed with severe endometriosis.