Catamenial pneumothorax with diaphragmatic perforation and herniation of endometrial tissue: a case report
This case report describes a 30-year-old woman with recurrent catamenial pneumothorax who underwent successful VATS repair of a diaphragmatic perforation with herniated endometrial tissue, providing direct intraoperative and histological evidence supporting the retrograde menstruation theory and demonstrating the efficacy of defect repair combined with pleurodesis without lung resection.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
For most people, the lungs and the uterus are separate worlds, one tucked safely inside the rib cage and the other deep within the pelvis. They are separated by a thick, muscular floor called the diaphragm, which acts as a barrier between the chest and the abdomen. However, in a rare condition known as catamenial pneumothorax, this barrier fails in a way that links the two directly to the monthly menstrual cycle. This condition occurs almost exclusively in women of childbearing age, where air suddenly leaks into the space around the lungs, causing the lung to collapse. What makes this phenomenon so puzzling is that the leak happens in perfect rhythm with menstruation, often just before or during a period. For decades, doctors have debated why this happens. Some theories suggest that tiny cells from the uterus travel through the blood or lymph system to the chest, while others propose that hormonal changes cause the lung tissue itself to crack. The most widely accepted idea, however, is that menstrual fluid flows backward from the uterus, through the fallopian tubes, and up into the abdomen, where it irritates the diaphragm and eventually punches a hole in it.
A team of surgeons and researchers recently captured a rare, direct view of this process in action, offering the clearest evidence yet for how these two distant parts of the body can become connected. They treated a thirty-year-old woman who had suffered from repeated episodes of collapsed lungs on her right side, each time occurring just before her period. Despite numerous scans that showed no obvious lung disease or cysts, her condition kept returning. The medical team decided to operate using a minimally invasive technique, inserting a small camera into her chest cavity. Crucially, they timed the surgery for the twenty-seventh day of her menstrual cycle, just before her period was due to start, hoping to catch the problem while it was active.
Inside the chest, the view was striking. While the lungs themselves looked healthy and free of any abnormal growths or holes, the muscular floor of the chest told a different story. The right side of the diaphragm was red and inflamed. At the very center of this muscle, the surgeons found a tiny hole, measuring six millimeters across. Through this small opening, tissue from the lining of the uterus was actually pushing up into the chest cavity, moving slightly with every breath the patient took. This was the missing link: a direct physical bridge where endometrial tissue, which normally lines the uterus, had herniated through a defect in the diaphragm. The surgeons carefully removed this protruding tissue and the surrounding hole, then stitched the muscle back together and roughened the inner chest wall slightly to help the lung stick to the chest and prevent future leaks.
The tissue they removed was sent to a laboratory for analysis, where it was confirmed to be endometrial tissue, the same kind that lines the uterus. Tests showed that this tissue was sensitive to the body's natural hormones, specifically estrogen and progesterone, which explains why the hole would open and close in sync with the menstrual cycle. This finding strongly supports the theory that menstrual fluid travels backward and upward, eventually wearing a hole in the diaphragm. The patient recovered quickly and, after four months of follow-up, had not experienced another collapsed lung. She chose not to take hormonal medication that would prevent pregnancy, as she wished to conceive in the future, and the surgery alone appeared sufficient to stop the recurrence.
This case is significant because it moves beyond theory to show the actual mechanism. While other studies have suggested that holes in the diaphragm are the cause, they have rarely seen the endometrial tissue itself pushing through the gap. By operating at the precise moment in the cycle when the tissue is most active, the team was able to see the herniation clearly. They also demonstrated that removing the hole and the tissue, without needing to cut away any part of the lung, was an effective solution. For a patient who wanted to preserve her ability to have children, this approach offered a cure without the side effects of long-term hormone suppression. The story of this patient highlights how a careful look at the timing of symptoms and a willingness to look directly inside the body can reveal the hidden connections that drive complex medical mysteries.
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