Thoracic Endometriosis in Monozigotic Twins

Endometriosis consists on the presence of functionally active ectopic endometrial tissue. The thorax is the most frequent extrapelvic location. The causes of endometriosis are not well known yet and involve both genetic and environmental factors. The aim of this article is not only to describe the case of thoracic endometriosis in two monozygotic twins, but also try to establish a relationship between: coincident characteristics and genetics, differences between both cases with environmental factors.