Peritoneal pockets and endometriosis. Confirmation of an important relationship, with further observations.

Of 132 women with endometriosis, almost one-fifth had peritoneal pockets. Two-thirds of the structures had endometriosis either around the rim or inside. Since one-third of the pockets lacked endometriosis and fibrosis was not present as a possible cause, endometriosis does not seem to have been the likely primary cause. Rather, such peritoneal invaginations and endometriosis may be ontologically related to a separate codevelopmental factor.