Types of Endometriosis — Disease Patterns That Guide Treatment

Our approach to typing endometriosis

Type is determined by a combination of expert ultrasound (ISUOG IDEA protocol), MRI mapping where deep disease is suspected, AMH testing where surgery on the ovary is being considered, and intra-operative findings if surgery is indicated. Typing is never a single-test diagnosis. We classify by location, depth, and anatomical pattern — then build the treatment plan from there.

Superficial peritoneal endometriosis

The most common form. Endometrial-like implants are confined to the peritoneum (pelvic lining) without significant depth. Surgically accessible and usually responsive to careful excision. Symptoms may still be severe despite limited visible disease — reinforcing that severity does not equate to extent.

Ovarian endometrioma (chocolate cyst)

The cystic form on the ovary, filled with old blood. Visible on routine ultrasound, well characterised by IDEA-protocol imaging. Treatment decisions are nuanced: cystectomy can reduce ovarian reserve, while leaving large endometriomas affects fertility differently. Where fertility preservation matters, we discuss IVF before surgery and the trade-offs in detail.

Deep infiltrating endometriosis (DIE)

The form that infiltrates beyond 5 mm into peritoneum, bowel wall, bladder, ureter, or other structures. Requires specialised pre-operative MRI mapping and an experienced multidisciplinary surgical team. ESGE recommends DIE surgery is performed in centres with sufficient case-volume and the ability to involve colorectal and urological colleagues where indicated.

Adenomyosis

Endometrial-like tissue within the uterine muscle. Often co-exists with endometriosis. Causes heavy menstrual bleeding, dysmenorrhoea, and affects implantation and pregnancy outcomes. Adenomyosis has its own diagnostic pathway and treatment options ranging from levonorgestrel-IUS to focal management to hysterectomy when fertility is no longer a goal.

Why typing matters

Treatment is fundamentally different across types. Superficial disease often responds to hormonal management alone. Deep infiltrating endometriosis requires precision excision surgery, often involving bowel or urological collaboration. Endometrioma management balances pain control, fertility preservation, and ovarian reserve protection. Adenomyosis has its own pathway. Typing first — then individualising treatment — is what differentiates specialist endometriosis care from generic gynaecological surgery.

Types of endometriosis covered in this section

Guidelines we follow

• ESHRE 2022 Guideline on Endometriosis — disease classification
• AAGL classification of endometriosis severity
• ESGE consensus on deep infiltrating endometriosis surgery
• ISUOG-IDEA consensus on sonographic typing of pelvic endometriosis

Where this fits

Type informs treatment decisions and feeds directly into the diagnostic pathway. For fertility implications by type, see endometriosis and fertility.