Background Ectopic deciduosis is a benign presence of endometrial tissue outside of the uterus during pregnancy that rarely presents with pleuropulmonary manifestations and recurrent pneumothorax. Case Description We report a 35-year-old woman at 15 weeks' gestation with a history of recurrent intrapartum right pneumothorax found to have pleural, pulmonary, and diaphragmatic lesions and a middle lobe air leak. Wedge resection of the middle lobe and mechanical pleurodesis was performed. Histopathological analysis was progesterone receptor and PAX8 positive consistent with ectopic deciduosis. Conclusion Ectopic deciduosis is a rare cause of recurrent pneumothorax in pregnancy and should be considered when evaluating these patients.