Endometriosis: Classification

Despite many attempts to make the disease comparable in expression, complaints, and sequelae, this has not been sufficiently successful. In particular, there is no correlation between the severity of findings and symptoms. In some countries, classification by localization is preferred:

  • Endometriosis genitalis interna (adenomyosis uteri) – endometriosis lesions within the myometrium of the uterus (uterine musculature).
  • Endometriosis genitalis externa – foci of endometriosis in the organs of the small pelvis, especially in the ovaries (ovaries).
  • Endometriosis extragenitalis – foci of endometriosis outside the pelvis, such as on the intestine, and less frequently on the lungs, brain or skin.

Internationally, the classification of the American Society for Reproductive Medicine (so-called rASRM staging (r= revised version)) has become accepted today. It distinguishes four degrees of severity. American Society for Reproductive Medicine Revised Classification of Endometriosis (rASRM).

Peritoneum Endometriosis infestation <1 cm 1-3 cm > 3 cm
superficial 1 2 4
deep 2 4 6
Ovary (ovary) R superficial 1 2 4
deep 4 16 20
L superficial 1 2 4
deep 4 16 20
Douglas infestation* Partial total
4 40

* Pocket-shaped bulge of the peritoneum (abdominal membrane) between the rectum (rectum) at the back and the uterus (uterus) at the front.

Ovary (ovary) Adhesions (adhesions) < 1/3 affected 1/3 -2/3 infested > 2/3 infested
R tender 1 2 4
fixed 4 8 16
L tender 1 2 4
fixed 4 8 16
Tube (Fallopian tube) R tender 1 2 4
fixed 4* 8* 16
L tender 1 2 4
fixed 4* 8* 16

* If the fimbrial apparatus of the fallopian tube is included, 16 points are automatically assessed.

Stage I minimal 1 – 5
Stage II Slightly 6 – 15
Stage III Moderate 16 – 40
Stage IV severe > 40

According to the EEC (Endoscopic Endometriosis Classification), which corresponds to the WHO staging, endometriosis is classified into the following four stages:

Stage Description of the stage
I
  • Endometriosis lesions in the small pelvis <5 mm
  • Endometriosis foci at the portio (transition from cervix to vagina) < 5 mm
  • Both tubes (fallopian tubes) freely passable
II
  • Endometriosis lesions in the small pelvis > 5 mm
  • Endometriosis foci at the portio > 5 mm
  • Endometriosis foci on the roof of the urinary bladder
  • Adhesions (adhesions) in the area of the ovaries (ovaries) or tubes with high-grade stenosis (narrowing) of the tubes
  • Endometriosis lesions in the space of Douglas.
III
  • Adenomyosis uteri
  • Endometriosis at the angle of the tube
  • Chocolate cysts of the ovaries
  • Endometriosis nodes on the ligamenta sacrouterinae
IV
  • Endometriosis outside the internal and external reproductive organs; foci possible throughout the abdomen, less commonly outside the abdomen (lungs, inguinal canal, skin, brain)

Because the American Fertility Society (AFS-) and Endoscopic Endometriosis Classification (EEC-) scores refer only to superficial endometriosis, severe forms of the disease in the retroperitoneal space are not included. The ENZIAN score is intended to complement the four stages (see above) to better reflect the extent of the disease and to allow assessment and comparability of therapeutic outcomes. Further subdivision into subgroups a, b, and c results from the localization of the disease.

  • Subgroup “a” describes the vertical compartment of Douglas’ space, vagina, and uterus.
  • Subgroup “b” includes the horizontal compartment with the ligamenta sacrouterinae (smooth muscle interspersed fibrous connective tissue tract that connects the cervix (cervix) with the sacrum (os sacrum)), the parametria (pelvic connective tissue in front of the cervix to the urinary bladder and on both sides to the lateral pelvic wall) to the pelvic wall, with reference to the possible involvement of the ureters (ureters).
  • Subgroup “c” refers to the dorsal (“backward”) vertical compartment of the rectovaginal septum (thin connective tissue partition (septum) between the vagina (vagina) and the rectum (rectum)) and the pararectal (“around the rectum”) space therein with the rectum (“rectum”). The extent of a possible sigmoid or rectal stenosis (narrowing) is also taken into account.