Types, Severity and Classification of endometriosis - adenomyosis

The endometrium is the tissue lining the inside of the uterus. The endometrium grows during the cycle and is shedded at menstruation.
Endometriosis : is by definition endometrial stroma and glands outside the uterus
Adenomyosis : endometrial stroma and glands in the myometrium of the uterus

Microscopy and activity of endometriosis.

deep endometriosis

is very active

Subtle endometriosis is morphologically very active
Typical endometriosis are burnt out lesions
Cystic ovarian endometriosis contains hardly any endometriotic cells in the wall.
Deep lesions are morphologically very active

The activity of endometriosis is sometimes used as argument to consider subtle endometriosis as ‘severe’ since active ; For this read the discussion on the pathophysiology

Clinical types of endometriosis

Clinically endometriosis varies from tiny little endometriosis to large chocolate cysts or invasive endometriosis. It is unclear whether subtle, typical, cystic, and deep endometriosis are 1 or several diseases

Subtle endometriosis : 1-3 mm superficial

white vesicle

polipoid lesion

Believed to be the early stages after implantation : these are small endometriosis (1 to 3 mm) which macroscopically look like white vesicles, red vesicles, or flame like endometriosis.

Subtle endometriosis can hide more severe deep endometriosis and are often associated with typical endometriosis. In the example below, subtle endometriosis are shown covering a deep endometriotic lesion whereas a typical endometriosis is visible in the left uterosacral ligament.
Subtle lesion are not a pathology and occur in 80% of a normal population. Subtle endometriosis can present very atypically and even mimic an ovarian cancer as shown below right. Another frequent mistake is to diagnose ‘endosalpingiose’ as endometriosis


red vesicle

white vesicle

white vesicle

Typical endometriosis : 0.5-4 cm superficial lesions

typical lesion bladder


Typical endometriosis are black puckered endometriosis generally in a white sclerotic area. They are 1 to 2 cm in diameter, but can cover much larger area’s. These endometriosis are found not only in the pelvis but also on the diaphragm.

Deep endometriosis often present as typical endometriosis.

Typical endometriosis can present atypically.

The recognition of subtle endometriosis was an historical mistake : indeed by pathology this fitted the definition of 1900 ‘endometrial glands and stroma outside the uterus’. Yet including subtle in mild endometriosis all women had endometriosis. It became debated in the early nineties but it took until 1999 when

Koninckx et all described the endometriotic disease theory to dismiss subtle endometriosis as a pathology.

Cystic ovarian endometriosis

Stripping of cyst

can mimic ovarian cancer

Cystic ovarian endometriosis are Chocolate cysts the ovary. These cysts are mostly 3-4 cm in diameter but can grow as large as 15 cm.
These cyst usually form adhesions with the pelvic wall and the other organs of the pelvis.
As a therapy stripping of the wall is the preferred technique. Medical therapy is ineffective
A cystic corpus luteum can mimic a cystic ovarian endometriosis

small cyst

laser incision


closure with glue

Deep endometriosis : solid tumors

Recto-vaginal nodule

deep after surgery

before surgery

Endometriosis can present as solid tumours up to 5 by 6 cm in diameter most frequently in the pouch of Douglas.
From the left picture it is obvious that this endometriosis is in close proximity of the vaginal wall (hence dyspareunia) and of the rectum (hence pain during bowel movement).
Other localizations are the sigmoid (not detectable clinically and easily missed during laparoscopy (except when the surgeon has great experience)and between the uterus and the bladder (hence bladder irritation and pain.

Images ofRectovaginal nodules : Type I II III

diameter of nodules

only the bigger are felt

our surgeries

central nodule
Bowel hides deep endometriosis
bowel hides deep
Deep endometriosis
Normal Rectoscopy
normal rectoscopy
Rectoscopy : more than 50% occlusion
partial occlusion

Endometriosis can involve the vesico-uterine fold

vesico-uterine fold

blue spots at cystoscopy

hidden nodule

Endometriosis can involve the ureter and the vagina

ureter involvement


vaginally visible

after excision

Endometriosis can also be found at the level of the sigmoid : unless looked for this endometriosis are missed at laparoscopy since situated higher outside the pelvis, as shown on the left image

sigmoid nodule

contrast enema to judge occlusion

50% occlusion

50% occlusion

The Ovarian remnant Syndrome

Go top

The ovarian remnant syndrome is fortunately rare. The literature is almost empty and I have not seen more than ten over the last 15 years. Diagnosis and surgery always are difficult.
The ovarian remnant syndrome should be thought of when a women following hysterectomy and ovariectomy has severe chronic pain, whereas at ultrasound (or other imaging techniques, a multi-cystic ovary is found with a suspicion of endometriosis). At laparoscopy as depicted below, almost invariably a frozen pelvis with encapsulated ovary is found : at dissection after identification of the ureter, is becomes immediately clear that the ureter is located inside the ovarian mass. Therefore the surgeon should be very experienced.


shows ureter

through the lesion

after resection


Nl Junctional zone

Thickened Junctional zone

focal andenomyosis

Transmural adenomyose

Transmural adenomyose


There is a lot of confusion
The definition is clear: stroma and glands in the myometrium. This is however a diagnosis by pathology made after hysterectomy.
The prevalence varies between 30 and 70% according to the number of slides investigated .
The diagnosis can be also tentatively made with imaging as ultrasound or MRI. Two types can be diagnosed : junctional zone thickening and focal adenomyosis. The biggest problem is that often diagnosis is only 70% accurate.
Adenomyosis is believed to be a cause of pain and infertility with little evidence
Adenomyosis is often an alibi to do an hysterectomy in women with chronic pain since theoretically adenomyosis is difficult to exclude

Peritoneal Pockets or Allen en Master syndrome

Allen en Masters

Allen en Masters

Allen en Masters

Allen en Masters

Peritoneal pockets are an unclear pathology Pockets in the peritoneum. They can be large and deep. Peritoneal pockets are believed to be associated with endometriosis
Excision is believed to be the right therapy. (click for images of surgery )

Haemorrhagic ascites

Endometriosis associated with haemorrhagic ascites is a rare condition. Can contain up to 6-10 litres and Is Believed to be similar to a Meigs syndrome

What is severe endometriosis - which classifications ??

History of classifications
1980 Acosta classification made a distinction between superficial and cystic ovarian endometriosis.
1985 AFS classification is a point scoring system. Essential I and II were superficial endometriosis, whereas III and IV cystic ovarian with adhesions.
1986 Subtle were described after this many women which beforehand were classified as ‘normal’ now became endometriotic.
1989 Deep was described

The definition of severe has become variable according to the authors
Severe = big endometriosis subtle are very small, typical generally small, cystic can be large cysts with a lot of adhesions, whereas deep can cause a lot of pain and are surgically the most challenging. Obviously a nodular lesion of 0.5 cm diameter and of 5 cm diameter is not the same.
severe = active endometriosis.By pathology subtle and deep are active endometriosis, whereas typical and cystic are generally inactive.
Severe=Surgically difficult

the rAFS Classification is a surgical classification without subtle and deep The rAFS is the most widely used classification. It is a point scoring system for diameter of endometriosis and for adhesions. It is an old surgical classification. Deep endometriosis are not represented : a most severe deep lesion of 5 cm can be classified as I.Classes I and II are superficial endometriosis (thus subtle or typical) of respectively less or more than 3 cm in diameter.-classes III and IV represent cystic ovarian endometriosis with adhesions.
The Leuven - AFS classification. adds subtle and deep endometriosis to the rAFS

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