Endometriosis: pathogenesis

Pathogenesis

There are many theories describing the pathogenesis of endometriosis. These theories can be classified into: 1) in-situ development 2) transplantation / implantation 3) combination of in-situ development and transplantation / implantation.

In-situ development -The cells of that site itself undergo differentiation and become endometrial cells	a)       Germinal epithelium of the ovary
	b)       Embryonic cell
	c)        Coelomic metaplasia
	d)       Metaplasia by inflammation
	e)       Metaplasia by hormonal stimulation
	f)        Metaplasia by induction
	g)       Secondary mullerian system
Transplantation / implantation -The endometrial cells from the uterus lining migrate to other sites	a)       Retrograde menstruation
	b)       Mechanical transplantation
	c)        Benign lymphogenous metastasis
Combination of in-situ development and transplantation/implantation

Among the most widely accepted theories include: 1) retrograde menstruation 2) coelomic metaplasia 3) benign lymphogenous metastasis.

In retrograde menstruation theory, it is said that the menstrual blood contain some viable endometrial tissues, which retrogradely shed into the peritoneal cavity and get attach to the peritoneal cavity, proliferate and produce endometriosis implant.

Coelomic metaplasia theory claims that formation of endometriosis implant is caused by metaplasia of the coelomic epithelium, perhaps induced by environmental factor.

Another theory suggests that shedding menstrual tissue travels from the endometrial cavity through lymphatic channels and veins to distant sites, for example outside the pelvic cavity.

Endometriosis