Endometriosis Stages
Endometriosis Stages & Classification Systems
Purpose of Endometriosis Classification Systems
A system of classification or staging of endometriosis is useful in order to better describe the disease, develop better diagnostic modalities and treatments as well as to enhance research and standardise communication between scientists and health professionals.
Endometriosis appears in many different forms with a wide variety of clinical presentations depending on the extension of the disease, organs affected and individual circumstances. Therefore a unified consensus classification system for the stages of the disease is not a simple task. The most used and best-known system was developed by the American Society for Reproductive Medicine (ASRM – formerly ASF).
The ASRM classification system is divided into four stages or grades according to the number of lesions and depth of infiltration: minimal (Stage I), mild (Stage II), moderate (Stage III) and severe (Stage IV).
The classification also uses a point system to try to quantify endometriotic lesions . This point system allows for a way to numerically scale the disease. A score of 15 or less indicates minimal or mild disease. A score of 16 or higher may indicate moderate or severe disease. As mentioned before, the severity or the score of the disease does not necessarily correlate to the level of pain or presence of other symptoms.
ARSM endometriosis stages:
| Endometriosis Stage | Manifestation of the Condition |
|---|---|
| Stage I (1-5 points) |
|
| Stage II (6-15 points) |
|
| Stage III (16-40 points) |
|
| Stage IV (>40 points) |
|
This points system has its limitations and doesn’t always accurately match the patient’s symptoms or likelihood to be able to fall pregnant.
The Endometriosis Foundation of America (Endofound.org) has therefore proposed a different classification using more descriptive categories. It uses the anatomical location and level of infiltration.
Endofound Endometriosis Classification
Category I: Peritoneal endometriosis
The most minimal form of endometriosis in which the peritoneum, the membrane that lines the abdomen, is infiltrated with endometriosis tissue.
Category II: Ovarian Endometriomas (Chocolate Cysts)
Endometriosis that is already established within the ovaries. These forms of ovarian cysts are of particular concern due to their risk of breaking and spreading endometriosis within the pelvic cavity.
Category III: Deep Infiltrating Endometriosis I (DIE I)
The first form of deep infiltrating endometriosis involves organs within the pelvic cavity. This can include the ovaries, rectum, uterus, and can significantly distort the anatomy of the pelvic organs.
Category IV: Deep Infiltrating Endometriosis II (DIE II)
The other more extreme form of DIE involves organs both within and outside the pelvic cavity. This can include the bowels, appendix, diaphragm, heart and lungs among others.