Multi-Loculated Catamenial Pneumothorax: A Rare Complication of Thoracic Endometriosis.

The presence of endometrial tissue outside the uterine cavity is known as endometriosis. Catamenial pneumothorax (CP) is a recurrent spontaneous pneumothorax that occurs in women of childbearing age. Thoracic endometriosis is a rare clinical entity, and CP is the most common presentation.