Transcoelomic and Lympho-Hematogenous Dissemination of Endometrioid Heterotopias – the Mechanism of Extragenital Endometriosis Formation

Abstract

Endometriosis nowadays still a disease with an undisclosed pathogenesis. This article demonstrates and explains the possibility of different variants of dissemination of endometrioid cells in the body with the formation of foci of extragenital endometriosis in organs and tissues remote from the pelvis, complementing and confirming the theory of utero-peritoneal reflux in the development of endometriosis as the most reasonable. Endometrioid heterotopias have a more developed lymphatic network compared to the normal endometrium due to active lymphangiogenesis, and, having a tendency to invasive growth, endometrioid heterotopia is a source of endometrioid cells spreading along the direction of lymph outflow from the most typical locations (pelvic organs) with damage to the inguinal and pelvic lymph nodes. Lymphatic dissemination in adenomyosis is observed in every fourth patient, which requires revision of the surgery protocol with excision of regional lymph nodes to prevent relapses. The presence of cases of pulmonary endometriosis and endometrioid liver cysts makes hematogenic dissemination of endometriosis from the primary source in the pelvic region obvious. The most frequent localizations of endometrioid heterotopias are located near the corresponding venous plexuses of the small pelvis, the outflow from which occurs mainly through the inferior vena cava, without anatomical obstacles for hematogenic dissemination of endometrioid cells with subsequent lung damage. For liver involment, it is likely that endometriosis in the distal parts of the colon is important, the venous outflow from which is directed to the portal vein system. Endometriosis of the diaphragm – is an example transcoelomic spread with predominant location on the right dome of the diaphragm, as the right subphrenic space communicates with the pelvic cavity through the right lateral channel, which justifies the possibility of such involments of the diaphragme in context of the theory of uteroperitoneal reflux.Thus, the theory of menstrual regurgitation and the theory of hemato-lymphatic dissemination are components of a single pathogenetic model of the distribution of endometrioid cells in the body.