Background: The thoracic cavity is the most frequent site of extrapelvic endometriosis. It exhibits a wide variety of clinical manifestations, such as chest pain, cough, and respiratory distress, and is frequently associated with pelvic endometriosis. Although histological confirmation is the gold standard for a definitive diagnosis, endoscopic identification of the affected area is often difficult. Narrow band imaging (NBI) is an imaging technique that emphasizes vascular structures and is reported to be useful in the diagnosis of pelvic endometriosis.
Case presentations: A 31-year-old woman and 39-year-old woman developed a recurrent right pneumothorax during their menstruation cycles. They both had no medical history suggesting pelvic endometriosis. We planned an elective video-assisted thoracoscopic surgery for the suspicion of thoracic endometriosis. In addition to white light alone, an NBI observation enhanced the microvasculature of the suspected lesions and allowed us to identify the affected area more clearly. Partial resections of the diaphragm were performed. Histopathological and immunohistochemical studies of each specimen confirmed the diagnosis of extrapelvic endometriosis.
Conclusions: NBI may improve the diagnostic accuracy for thoracic endometriosis, especially in clinically suspected patients but without a history of pelvic endometriosis.
Keywords: Catamenial pneumothorax; Narrow band imaging (NBI); Thoracic endometriosis.