Most Common Type of Ureteric Endometriosis
The extrinsic form is the most common type of ureteric endometriosis, accounting for approximately 75% of all cases, where endometriotic tissue is localized to the adventitia or surrounding connective tissue of the ureter rather than within the ureteral wall itself. 1
Classification of Ureteric Endometriosis
Ureteric endometriosis is classified into two distinct anatomical patterns based on the location of endometriotic tissue relative to the ureteral wall:
Extrinsic Ureteric Endometriosis (Most Common)
- Represents approximately 75% of all ureteric endometriosis cases 1
- Endometriotic tissue is located in the adventitia or surrounding connective tissue of the ureter 1
- Occurs four times more frequently than the intrinsic form 2
- In histological analysis of 84 cases, 77% showed endometriotic tissue pattern while 23% showed fibrotic tissue only 3
- Extrinsic disease with obstruction requires more aggressive surgical intervention, typically resection and reimplantation, with therapeutic success rates of 84% 4
Intrinsic Ureteric Endometriosis (Rare)
- Represents approximately 25% of cases 1
- Endometrial cells are located within the ureteral wall itself 5
- Presents as a tumor-like mass engulfing the ureter 1
- More often requires aggressive surgical intervention 1
- Has significantly higher recurrence rates (60%) when treated with endoureterotomy approaches 4
Clinical Significance of This Distinction
The extrinsic versus intrinsic classification has critical implications for both diagnosis and treatment:
- Diagnostic approach differs: Extrinsic disease is more readily identified on renal imaging, while intrinsic disease often requires ureteroscopy or laparoscopy for definitive diagnosis 5
- Surgical planning varies: Extrinsic disease without obstruction may be managed with ureterolysis (shaving), while extrinsic disease with obstruction requires resection and reimplantation 4
- Prognosis differs substantially: Intrinsic disease has inadequate response to endoureterotomy (60% recurrence) compared to the 84% success rate with appropriate surgical management of extrinsic disease 4
Associated Clinical Context
- Urinary tract endometriosis occurs in approximately 1% of all endometriotic lesions 1
- The ureter is the second most common site of urinary tract involvement after the bladder 4
- Approximately 30% of patients have reduced kidney function at the time of diagnosis 1
- The left ureter is more commonly affected than the right 5
- Presence of hydroureteronephrosis shows significant association with endometriotic tissue pattern (68%) versus fibrotic pattern (42%) 3