Endometriosis: how does it happen?

Endometriosis is a condition in which normal endometrial tissue is located somewhere outside the uterus. The misplaced endometrial tissue is commonly within theÂ pelvis (ovaries,Â uterine ligaments,Â pouch of Douglas, fallopian tubes, rectovaginal septum) and is often multifocal. Less commonly, it is foundin remote sites, such as lymph nodes, lungs, heart, skeletal muscle, or bone. Commonly, endometriosis appears as an ovarian cyst, which, when ruptured, oozes a dark brown, hemorrhagic material; such cysts are called “chocolate cysts.”Â Endometriosis is totally benign. However, it causes problems because it undergoes cyclic bleeding, like normal endometrium. Depending on the location, it may cause scarring, pain, or sterility.

So how does the endometrium get out of the uterus?

Well, that’s still a mystery. There are three mainÂ theories, none of which is alone entirely satisfactory:

1. The regurgitation theory. Menstrual flow backs upthrough fallopian tubes, with subsequent implantation of endometrial tissue in the peritoneum. Retrograde flow occurs pretty commonly in normal women, and menstrual endometrium isÂ viable (if injected into the peritoneum, it lives). This is a nice theory for endometriosis in the pelvic cavity.

2. Metaplastic theory. Endometrial tissue arises from endometrial differentiation of coelomic epithelium. This could be trueÂ (embryologically, endometrium arises from coelomic epitheilium), and would be especially likely to cause endometriosis in sites such as the ovary.

3. Vascular/lymphatic dissemination theory. Endometrial cells somehow work their way into the vascular/lymphatic system. This hypothesis would explain how endometriosis can occur inÂ distant sites, such as lymph nodes or lungs.

Perhaps all three theories are correct, either concurrently, or at different times in different patients.

More pathology!

4 Comments

Nancy P, Pili on May 16, 2011 at 12:25 am

Thank’s for the information about endemetrios,Im searching this subject because Im suffering endemetriosis again.Ihave done in laparoscopic surgery last 2002 succesfully I have two kids now and we are planning to have another one but unfortunately the pain strike again and I am planning to go to my OB-Gyne.

Pratibha Devi Sharma on August 10, 2013 at 2:03 am

I just received my Endometrial biopsey report (done on 23.07.2013. Report says “Biopsey comprises predominantly of hemorrhagic material with scanty endometrial tissue for assessment comprising of few benign tubular glands and small clumped stromal fragment. Negative for GRANULOMA/MALIGNANCY”
I do not understand this. Will anybody help me to understand the report.

Kristine on August 10, 2013 at 10:19 am

Hi there – the report means that there was some normal-looking endometrial tissue in the specimen (“benign tubular glands and small clumped stromal fragment” is just normal tissue). Negative for granuloma means they didn’t see anything that looked like a reaction to a fungal infection, or any other type of granuloma (a granuloma is just a collection of macrophages – you can get them for lots of reasons). Negative for malignancy means that they didn’t see any cancer in the specimen. This is all good!

Caustic on July 30, 2016 at 2:20 pm

Thanks for this, it has been very helpful
Short and clear
Be blessed

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Nancy P, Pili on May 16, 2011 at 12:25 am

Thank’s for the information about endemetrios,Im searching this subject because Im suffering endemetriosis again.Ihave done in laparoscopic surgery last 2002 succesfully I have two kids now and we are planning to have another one but unfortunately the pain strike again and I am planning to go to my OB-Gyne.
Pratibha Devi Sharma on August 10, 2013 at 2:03 am

I just received my Endometrial biopsey report (done on 23.07.2013. Report says “Biopsey comprises predominantly of hemorrhagic material with scanty endometrial tissue for assessment comprising of few benign tubular glands and small clumped stromal fragment. Negative for GRANULOMA/MALIGNANCY”
I do not understand this. Will anybody help me to understand the report.
Kristine on August 10, 2013 at 10:19 am

Hi there – the report means that there was some normal-looking endometrial tissue in the specimen (“benign tubular glands and small clumped stromal fragment” is just normal tissue). Negative for granuloma means they didn’t see anything that looked like a reaction to a fungal infection, or any other type of granuloma (a granuloma is just a collection of macrophages – you can get them for lots of reasons). Negative for malignancy means that they didn’t see any cancer in the specimen. This is all good!
Caustic on July 30, 2016 at 2:20 pm

Thanks for this, it has been very helpful
Short and clear
Be blessed