Endometriosis is defined as the abnormal presence of endometrial tissue, including endometrial glands and stroma, outside the uterine cavity. The term “thoracic endometriosis” is classically referred to the respiratory manifestations which classically result from the presence and the cyclical changes of endometrial tissue in one of the thoracic structures.

Although thoracic endometriosis is rare, four clinical entities are well-recognized: pneumothorax, hemothorax, haemoptysis and pulmonary nodule, with a respective frequency of 73%, 14%, 7% and 6%. These are characterized by the recurrence of symptoms within the menstruations, in women aged between 30 and 40, and mainly in the right hemi-thorax. Pelvic endometriosis is usually, if not constantly, associated. Catamenial pneumothorax is not always related to thoracic endometriosis and its mechanisms remain unclear. An exploratory and therapeutical surgery is required in most of the cases. Video-assisted-thoracoscopy is the best current approach of catamenial pneumothorax. It may visualize pathognomonic pleuro-diaphragmatic abnormalities, including diaphragmatic fenestrations and/or endometrial implants, in about one third of the patients. Surgical treatment is justified because of the frequent relapses under medical treatment alone. Surgery consists of diaphragmatic repair and excision of all apparent endometrial implants; pleural abrasion may complete the procedure. A combined prolonged hormonal therapy is increasingly recommended, Danazol or GnRH analogs being advantaged.

Further prospective studies are needed to estimate the real incidence of thoracic endometriosis and to devise the best therapeutical option.

Thoracic endometriosis is probably rare but its diagnosis is easy when accurately raised. The approach is multidisciplinary involving a pneumologist, a thoracic surgeon and a gynecologist.