The Mysterious Link: Exploring the Hidden Origins of Catamenial Pneumothorax

Abstract Catamenial pneumothorax (CP) is a rare subtype of spontaneous pneumothorax (SP) that primarily affects women aged 30-40, often associated with thoracic endometriosis. CP constitutes 3-6% of SP cases in menstruating women, showing a right-sided predominance (85-95%). Approximately 80 cases have been documented globally. CP typically presents with chest pain, dyspnea, and non-productive cough, within 72 hours of menstruation. While associated with endometriosis, a connection to adenomyosis involving uterine-like tissue growing into the uterine wall has not been reported. We present the first known case of CP associated with uterine adenomyosis. A 42-year-old female with history of adenomyosis and multiple unsuccessful in vitro fertilizations experienced four episodes of pneumothoraces over two years, each correlating with her menstrual cycle. First and second episode occurred two years ago and resolved spontaneously, while the third required hospitalization, video-assisted thoracoscopic surgery (VATS) with right upper lobe segmentectomy and doxycycline pleurodesis. Patient presented with new onset shortness of breath three days after flying from San Diego to Honolulu, with menstruation beginning two days post-flight. Chest CT scan revealed a right-sided pneumothorax and trace pleural effusion. Thora-Vent® chest tube was inserted, initially resolving the pneumothorax. Follow-up imaging showed recurrence, leading to VATS with talc pleurodesis. Patient's symptoms resolved and she was discharged without recurrence. CP often goes unrecognized due to its rarity and potential misdiagnosis from inadequate medical history. Management typically involves surgical interventions such as bullectomy, pleurodesis, hormonal therapy, or hysterectomy with salpingo-oophorectomy. Previous doxycycline pleurodesis was ineffective, while current literature suggests talc slurry pleurodesis may yield better outcomes. Although ectopic endometrial tissue deposition is commonly considered an etiological factor, the pleural biopsy in this case showed no evidence of such tissue. Thoracic intercostal musculature was not biopsied. This case suggests that, in the presence of adenomyosis, ectopic endometrial tissue may invade the pleural space, mimicking CP's pathophysiology. Absence of endometrial tissue in the pleural biopsy raises questions about alternative mechanisms, such as inflammatory processes or other unexplained pleural layer shedding associated with menstruation as it relates to adenomyosis. We report the first known case of CP in a patient with adenomyosis, highlighting the need for integrating menstrual and gynecologic history and consideration of pleural biopsy in appropriate clinical setting. Treatment options, such as talc versus doxycycline pleurodesis, can enhance diagnostic accuracy and care. Continued research into the correlation between adenomyosis and CP is essential for improving diagnosis and recognizing adenomyosis as a potential risk factor.