Microscopy of endometriosis.

Subtle endometriosis are active lesions.
Typical endometriosis are inactive burnt-out lesions.
Cystic ovarian endometriosis is inactive, with few endometriosis cells in the wall.
Deep lesions are superficially inactive but active when deeper than 5mm. Read our recent paper on peritoneal fluid

Deep endometriosis mophology

Deep endometriosis

Deep endometriosis

Deep endometriosis is active

Superficial endo

Subtle lesions

In 1986 non pigmented lesions were recognized as endometriosis, probably early stages. They are small (1 to 3 mm) white or red vesicles, or polypoid or flame-like endometriosis.

They occur together with other lesions and can hide severe deep endometriosis. If the surgeon does not recognise de deep endo under superficial lesions it will be missed: in the image below, subtle endometriosis covers a deep endometriosis lesion and typical endometriosis is visible in the left uterosacral ligament.
Subtle lesions are very frequent and occur in up to 80% of a normal population. Subtle endometriosis can be atypical and even mimic ovarian cancer as shown below right. A frequent mistake is to misdiagnose ‘endosalpingiosis’. Recently our understanding was updated by understanding the progesterone resistance.

Typical endometriosis

Typical endometriosis or gunshot lesions are 1 to 2 cm or larger black puckered endometriosis in a white sclerotic area, in the pelvis and on the diaphragm. 50% are painful up to 3cm distance 

Cystic ovarian endometriosis

Cystic ovarian endometriosis, or chocolate cysts in the ovary,  are mostly 3-6 cm in diameter but can be much larger or smaller.
These cysts usually are fixed to the pelvic wall and other organs of the pelvis.
Stripping of the wall is the preferred technique since less recurrences. However, more recently, superficial treatment was reconsidered see our recent publication  Medical Therapy is ineffective
A cystic corpus luteum can mimic a cystic ovarian endometriosis

Deep endometriosis: solid tumours

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 to the vaginal wall, causing dyspareunia and of the rectum, causing 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.

Deep endometriosis of the rectovaginal septum

rectoscopy is generally normal; only the larger ones are felt

Deep endo of the vesico-uterine fold  and the ureter

Deep endo of the sigmoid

is easily missed during laparoscopy and is generally underestimated ; it is  difficult surgery.

Fot this reason we think that a contrast enema remains the only reliable method to judge occlusion


The definition is clear: endometrial stroma and glands in the myometrium. The prevalence varies between 30 and 70% according to the number of microscopical slides investigated .
There are 3 types of adenomyosis

  • thickening of the junctional zone
  • diffuse adenomyosis
  • nodular adenomyosis

Adenomyosis is a cause of pain and infertility

The Ovarian Remnant Syndrome: endometriosis

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 woman 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 the encapsulated ovary is found: at dissection, after identification of the ureter, it becomes immediately clear that the ureter is located inside the ovarian mass. Therefore the surgeon should be very experienced.

click for presentationovarian remnant

article pockets

Read our recent paper

Haemorrhagic ascites Endometriosis

Endometriosis associated with haemorrhagic ascites is a rare condition and the abdomen can contain 6-10 litres. We believe as published, the mechanism is similar to a Meighs syndrome 2008_ussia_ascites

Severe Endometriosis

Severe means 

  • Difficult surgery: deep endometriosis  > cystic ovarian endometriosis >> typical endometriosis
  • many surgeons refer to rAFS classes III and IV, which are cystic ovarian endometriosis
  • Without video registration, the severity is often exaggerated by surgeons


  • 1980 Acosta classification made a distinction between superficial and cystic ovarian endometriosis. Then Kistner, which is similar
  • 1985 rAFS classification is a point scoring system. Classes I and II were superficial endometriosis, whereas III and IV were cystic ovarian with adhesions,  as we described in 1991
  • 1986 Subtle lesions were described: after this, many women who beforehand were classified as ‘normal’ now had endometriosis.
  • 1990 we described deep endometriosis 
  • 2011 we published a comprehensive discussion, which recently was translated into the ENZIAN classification and the new AAGL classification
2011_koninckx_ classification of endo

Our analysis how to classify endometriosis in 2011

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