Catamenial pneumothorax due to heterotopic endometriosis in the pericardium

A 46-year-old woman presented with a right pneumothorax at a regular medical examination during menstruation. The pneumothorax resolved without intervention; however, 6 months later, she was referred to our hospital due to chest pain and dyspnoea. A chest X-ray showed grade III pneumothorax and surgery was performed. During surgery, the patient was found to have pleural adhesions around the right upper lung, pores in the diaphragm and a blueberry spot in the pericardium. The margins of the upper lobe and diaphragm were covered with a polyglycolic acid sheet at the operation. Eight days after surgery, she was referred to our hospital again due to massive haemothorax. The reoperation suggested that the aforementioned blueberry spot in the pericardium was the source of bleeding. The spot was resected and shown to be oestrogen and progesterone receptor-positive, providing evidence of heterotopic endometriosis.

pneumomediastinum, pneumothorax

Catamenial pneumothorax (CP) is an unusual condition affecting premenopausal women and commonly misdiagnosed as simple pneumothorax. The diagnosis of CP highly depends on the surgical findings, but it is often difficult to detect characteristic findings, such as a blueberry spot, because they are continuously changing with the menstrual cycle. With awareness of thoracic endometriosis and full examination of the chest cavity and diaphragm, the reported incidence of CP is rising.1 However, CP due to endometriosis in the pericardium is quite rare. We report a case of CP that developed recurrent pneumothorax and haemothorax with a blueberry spot in the pericardium. Case presentation A 46-year-old woman presented with right pneumothorax on chest X-ray during a regular medical examination at her workplace during menstruation. She has a history of dysmenorrhoea associated with endometriosis and had undergone laparoscope-assisted surgery at the age of 29. She visited our hospital and was diagnosed with grade I right pneumothorax. As the patient had no symptoms, intervention was withheld and the pneumothorax resolved. However, 6 months later, she was referred to our hospital due to chest pain and dyspnoea. On admission, the patient was conscious and her vital signs were as follows: temperature, 36.4°C; blood pressure, 104/67 mm Hg; heart rate, 99 beats/min and respiratory rate, 20 breaths/min. Her oxygen saturation was 97% breathing room air. A physical examination revealed no abnormal findings except for remarkably decreased respiratory sounds in the right lung. Laboratory data showed no specific findings. A chest X-ray showed grade III right pneumothorax (figure 1A) and a chest drainage tube was immediately placed, and her symptoms was relieved. We suspected CP because her pneumothorax repeatedly correspond to the menstrual cycle. Meanwhile, CT images demonstrated bullous emphysematous findings in apical portion of the right lung. So thoracoscopy was planned to explore the inside of the thoracic cavity including the diaphragm on day 5 of admission. Investigations During the operation using video-assisted thoracoscopy, localised pleural thickening and adhesions were found around the right upper lobe of the lung, and four pores were found in the diaphragm (figure 2A). Pleural adhesions were also found in the middle lobe of the lung and part of the pericardium, and a blueberry spot was observed in the pericardium, suggesting heterotopic endometriosis (figure 2B). The blueberry spot was 5 mm in size located in the pericardium and formed adhesion to the middle lobe of the lung. Partial resection of the right upper lobe and the diaphragm was performed. Both margins of the upper lobe and diaphragm were covered with a polyglycolic acid sheet and autologous blood. The patient was discharged on day 11. On day 13, she was referred to our hospital by ambulance because of sudden onset right chest and back pain. A chest X-ray showed right pleural effusion (figure 1B) and chest CT showed high density pleural fluid. Chest tube revealed 500 mL of bloody drainage, so we decided to reoperate to detect the source of the bleeding. The reoperation was performed as video-assisted thoracic surgery. A massive haematoma was found around the right middle lobe of the lung and pericardium. The amount of removed intrathoracic blood was 220 mL. Two hundred and ten grams of haematoma was also removed. The aforementioned blueberry spot in the pericardial surface was thought to be the source of bleeding and resected. Outcome and follow-up Pathological specimens from the resected pericardium were demonstrated oestrogen and progesterone receptor-positive, which provided evidence of heterotopic endometriosis (figure 3). Hormonal therapy was administered using goserelin acetate and dienogest, and the patient had no recurrence during the follow-up period.

Pericardial endometriosis is an exceedingly rare condition. There is only one reported case of histologically proven endometriosis of the pericardium in the literature, which manifested with ascites and pleural and pericardial effusion.2 In the report, diaphragmatic and pericardial endometriosis was considered a consequence of retrograde regurgitation of endometrial cells, which pass through the oviducts into the peritoneal cavity and proliferate in ectopic sites. The transportation of viable cells in peritoneal fluid following a clockwise circulation pattern from the pelvis up the right gutter to the right hemidiaphragm has been suggested to be a cause of the development of asymmetric distribution of ectopic endometrium in the diaphragm. The first case of recurring pneumothorax in relation to menses was reported in the 1950s,3 and CP was defined by Lillington et al.4 It is accepted that 3%–6% of cases of primary spontaneous pneumothorax in women meet the definition of CP, but recent studies indicate that CP comprises approximately one-third of all spontaneous pneumothorax in women.5 Awareness of the disease may lead surgeons to inspect the diaphragmatic area in all premenopausal women with pneumothorax during surgery. In the current case, we noticed a blueberry spot in the pericardium during the first operation for pneumothorax, which suggested heterotopic endometriosis, but we did not resect the spot because there was no bleeding at that time. A chest CT scan demonstrated bullous emphysematous findings in apical portion of the right lung, but no endometriosis-related lesions were detected. During the second operation for haemothorax, it was considered to be caused by detachment of the blueberry spot of heterotopic endometriosis on the pericardium. When a young woman presents with pneumothorax, particularly during menses, CP should be suspected. Careful exploration, not only of the diaphragm, especially in the right side, but also of the pericardium is essential to achieve accurate diagnosis of CP. Recently, Ciriaco et al6 summarised that MRI showed high accuracy in the detection of diaphragmatic and pericardial endometriotic lesions, visceral or parietal pleural or bronchopulmonary endometriosis in a review article. A chest–abdomen MRI might be one of the pre-surgical procedures in suspicion of thoracic endometriosis. At the time of surgery, if any defect or endometrial implantation is detected, all defects should be restored, and all lesions should be resected if possible. Surgical treatment alone is not enough to prevent recurrence of CP, and hormonal treatment is considered to have an additional effect.7 Learning points. When a young woman presents with pneumothorax, particularly during menses, catamenial pneumothorax should be suspected. Surgical procedures are warranted for careful exploration of the diaphragm and pericardium. If heterotopic endometriosis is detected, it should be resected to confirm the diagnosis and prevent pneumothorax and/or haemothorax. Footnotes Contributors: YT, DM and NI contributed by conception and design, acquisition of data or analysis, interpretation of data and drafting the article. YT and NF contributed by drafting the article and gave a final approval of the version published. Funding: This study was funded by Ministry of Health, Labor, and Welfare, Japan (180101-02). Competing interests: NF reports grants from KISSEI and MSD, grants and personal fees from ONO, Bristol-Meyers Squib, Kyorin, personal fees from Chugai and personal fees from Daiichi Sankyo. Patient consent for publication: Obtained. Provenance and peer review: Not commissioned; externally peer reviewed.

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