Catamenial Pneumothorax With Pulmonary Fistula Identified During Surgery.

A 41-year-old woman was admitted with a recurrent pneumothorax coincident with menstruation 2 months after a first occurrence. Video-assisted thoracic surgery was performed for definitive diagnosis and pneumothorax treatment. Bluish diaphragmatic spots and three lung bullae were noted. A lung fistula was observed in one of the bullae, and the diaphragmatic lesion and bullae were resected. The bulla with air leakage and the diaphragmatic lesion were diagnosed as endometrial tissue by pathology. This case is rare as a fistula from a bulla with endometriosis was identified intraoperatively, suggesting the check-valve mechanism might be one of the etiologies of catamenial pneumothorax.