Persistent pneumothorax during pregnancy revealing histologically confirmed thoracic endometriosis

A 31-year-old gravida 1 para 0 woman at 27 weeks’ gestation was referred after an incidental right pneumothorax was identified during routine fetal ultrasonography. She reported mild dyspnea without hemodynamic instability. Two years earlier, she had experienced two episodes of right spontaneous pneumothorax that resolved with conservative oxygen therapy. Her medical history was notable for pelvic endometriosis diagnosed in 2010, for which she had previously received hormonal therapy. Chest radiography confirmed a moderate right pneumothorax. Despite supplemental oxygen and placement of a small-bore thoracic catheter, persistent air leakage continued, with repeated lung collapse after discontinuation of thoracic suction. She was discharged with a portable drainage system but returned a week later, because of worsening dyspnea requiring tube replacement for persistent air leak. A multidisciplinary conference involving thoracic surgery, obstetrics, anesthesiology, pediatrics, and neonatology concluded that persistent maternal hypoxemia posed a greater fetal risk than general anesthesia and thoracoscopic surgery. Obstetric evaluation confirmed fetal viability and no contraindication to surgery at this gestational age. The patient underwent three-port VATS. Intraoperative exploration demonstrated bullous lesions of the right middle lobe together with abnormal diaphragmatic lesions suspicious for thoracic endometriosis ( Fig. 1 ). Wedge resection of the right middle lobe including the bullae ( Fig. 2 ) and partial diaphragmatic resection with primary repair were performed ( Fig. 3 ). Operative time was 33 min with negligible blood loss. Intraoperative findings demonstrating diaphragmatic endometriotic lesions and holes. Intraoperative findings demonstrating bullous lesions of the right middle lobe. Primary repair of diaphragmatic lesion after resection of diaphragm. Histopathologic examination demonstrated endometrial glands and stroma involving the pulmonary parenchyma, pulmonary bulla, and diaphragm. Immunohistochemistry showed estrogen receptor and CD10 positivity, confirming TES. Postoperatively, the lung remained fully expanded without recurrent air leak. The remainder of the pregnancy was uneventful, and the patient subsequently delivered a healthy 3.2-kg female infant at 40 weeks’ gestation without maternal or neonatal complications.

TES is the most common cause of catamenial pneumothorax but is rarely considered during pregnancy because menstruation and ovulation are physiologically suppressed. Consequently, persistent pneumothorax during pregnancy is generally attributed to primary spontaneous pneumothorax or other pulmonary disorders. This case demonstrates that pregnancy does not necessarily eliminate thoracic endometriosis. Previously established pulmonary and diaphragmatic endometriotic implants may continue to produce structural abnormalities capable of causing recurrent or persistent pneumothorax despite hormonal suppression. There are five important points to be learn from this case. First, pregnancy does not exclude thoracic endometriosis. Thoracic endometriosis is classically associated with menstruation, but established thoracic lesions may remain clinically active during pregnancy. Once pulmonary cysts or diaphragmatic defects have developed, pneumothorax may occur independently of menstrual cycling. Secondly, persistent air leak should prompt reconsideration of the diagnosis. Pregnant patients with recurrent right-sided pneumothorax, particularly those with a history of pelvic endometriosis, should be evaluated for thoracic endometriosis even when classical catamenial timing is absent. Third, maternal oxygenation takes priority in treatment of pneumothorax. Persistent maternal hypoxemia may compromise fetal oxygen delivery. In appropriately selected patients, definitive treatment may be safer than prolonged conservative management. Fourth, VATS provides both diagnosis and definitive treatment as in this case. Thoracoscopy permits complete pleural exploration, identification of diaphragmatic disease, pulmonary wedge resection, diaphragmatic repair, and pathological confirmation of thoracic endometriosis in a single procedure. Even in a pregnant patient, VATS exploration can be safely done. Lastly, multidisciplinary care is essential. When suspicious for thoracic endometriosis, management should involve thoracic surgery, maternal–fetal medicine, anesthesiology, neonatology, and pathology to optimize maternal and fetal outcomes. The published literature describing pregnancy-associated thoracic endometriosis remains extremely limited. Most reported patients were initially managed with tube thoracostomy, with definitive surgery either delayed until after delivery or performed only after recurrent pneumothorax or prolonged air leakage. Histologic confirmation has frequently been incomplete, and detailed obstetric and neonatal outcomes have rarely been reported. In contrast, our patient underwent definitive thoracoscopic treatment during the third trimester, with pathological confirmation of endometriosis involving the pulmonary parenchyma, pulmonary bulla, and diaphragm by estrogen receptor and CD10 immunohistochemistry, followed by uncomplicated continuation of pregnancy to term and delivery of a healthy 3.2-kg infant. These findings support timely multidisciplinary surgical management when persistent pneumothorax compromises maternal respiratory function.

Thoracic endometriosis syndrome (TES) is an uncommon manifestation of ectopic endometrial tissue involving the pleura, diaphragm, and pulmonary parenchyma. Catamenial pneumothorax is the most common clinical manifestation of TES, accounting for ~70%–80% of presentations, and classically occurs within 72 h before or after the onset of menstruation [ 1–3 ]. The disease predominantly affects women in their third and fourth decades and demonstrates a marked right-sided predominance, with diaphragmatic endometriosis identified in ~90% of surgically explored patients [ 2 , 3 ]. Pregnancy has traditionally been considered protective against thoracic endometriosis because ovulation and menstruation cease and elevated progesterone levels induce decidualization of ectopic endometrial tissue [ 1 ]. Consequently, spontaneous pneumothorax during pregnancy is rare, and thoracic endometriosis is seldom included in the differential diagnosis. Current recommendations for the management of spontaneous pneumothorax during pregnancy are largely extrapolated from the nonpregnant population because of the paucity of disease-specific evidence [ 1–6 ]. To our knowledge, only a few cases of thoracic endometriosis presenting during pregnancy have been reported [ 7–10 ], and histologically confirmed pulmonary and diaphragmatic endometriosis treated by video-assisted thoracoscopic surgery (VATS) during pregnancy remains exceptionally rare. We report a case of persistent pneumothorax during the second trimester of pregnancy caused by histologically confirmed thoracic endometriosis, demonstrating that minimally invasive thoracic surgery can be safely performed during pregnancy within a multidisciplinary framework while achieving favorable maternal and neonatal outcomes.