Thoracic Endometriosis & Catamenial Pneumothorax | A Real Clinical Case

A 34-year-old woman develops sudden pleuritic chest pain and dyspnoea a few days after laparoscopic ovarian surgery. The obvious explanation seems postoperative — until the timeline reveals a clue that completely changes the diagnosis. In this episode of Medical Detective, we work through the case step by step: bedside recognition of pneumothorax, the initial postoperative differential, the importance of chronology, recurrence with menstruation, thoracic endometriosis, catamenial pneumothorax, VATS findings, histopathology, diagnostic reasoning errors, and a practical approach to management. This case is especially useful for medical students, residents, physicians, emergency clinicians, pulmonologists, gynaecologists, and anyone interested in clinical reasoning. Key learning points: • Stabilize pneumothorax before searching for the cause • Recent surgery can become a powerful diagnostic anchor • In reproductive-age women with spontaneous pneumothorax, always ask about menstrual timing • Recurrent right-sided pneumothorax around menstruation should raise suspicion for catamenial pneumothorax • Thoracic endometriosis may be missed on CT and may require VATS for diagnosis • Pelvic endometriosis strengthens suspicion but does not by itself prove thoracic disease Presented for medical education with written patient consent. This video is intended for educational purposes and does not replace individualized clinical judgment or medical care.