Intrinsic ureteric obstruction secondary to endometriosis: a rare clinical entity causing obstructive uropathy and renal failure

Ureteral endometriosis is rare and can be a silent clinical entity, which can potentially lead to serious complications such as obstructive uropathy, sepsis and renal failure. A high clinical suspicion is required especially in childbearing age groups due to non-specific presentation such as renal colic, recurrent urinary tract infection (UTI), renal failure or asymptomatic hydronephrosis. A woman in her 40s presented with febrile UTI and flank pain. She reportedly suffered from recurrent UTIs in the past. Initial workup revealed an infected, obstructed left renal collecting system with gross hydronephrosis and hydroureter to the distal ureter on a significant gynaecological background of severe endometriosis requiring hysterectomy in the past. CT showed chronic obstructive changes and soft tissue nodules within the renal pelvis with no radio-opaque stones. She underwent emergent ureteric stent insertion. Functional imaging demonstrated only 1% contribution of the left kidney with a preserved estimated glomerular filtration rate of 65 mL/min/1.73 m2. Endoscopic evaluation of ureters found extensive soft tissue lesions throughout the dilated left collecting system with biopsy-confirmed endometriosis. Subsequently, she underwent laparoscopic nephroureterectomy due to extensive ureteric involvement and chronically obstructed non-functioning kidney. Histopathology demonstrated completely obstructing ureteral endometriosis. Ureteric obstruction secondary to endometriosis can be due to extrinsic or intrinsic disease. In addition to initial assessment with CT urogram MRI may be helpful to evaluate soft tissue thickening. Endoscopic assessment with ureteroscopy and biopsy is required for tissue diagnosis. Surgery is often the treatment of choice, ranging from ureteroureterostomy, ureteroneocystostomy or nephroureterectomy in severe cases. Ureteral endometriosis is a rare clinical entity, clinicians should remain vigilant about common presentations of this rare entity, early diagnosis and prompt treatment is crucial to prevent progression to renal failure.

Urology, Obstetrics and gynaecology

While endometriosis may affect up to 15% of women of childbearing age, ureteral endometriosis is a rare and potentially silent clinical entity, which can progress to serious complications, namely obstructive uropathy, sepsis and renal failure.1 2 High clinical suspicion is required especially in women of reproductive age due to non-specific presentations such as loin pain, recurrent urinary tract infection (UTI) renal failure or asymptomatic hydronephrosis.1 2 Case presentation A woman in her late 40s presented with fever and left flank pain on a background of recurrent UTIs. She is a mother of one and has completed her family. She previously underwent an open abdominal hysterectomy due to heavy periods. oophorectomy was not performed as per patient preference. At the time of assessment, no other endometriosis manifestations or pelvic endometriosis were noted. On further assessment, initial blood work showed an estimated glomerular filtration rate of 65 mL/min/1.73 m2. CT (figure 1) showed gross hydronephrosis and hydroureter to the distal ureter with cortical thinning suggesting chronic obstruction and potential soft tissue nodules within the renal pelvis. There was no evidence of calculus. A ureteric stricture was suspected. In the context of an obstructed kidney with infective signs, left ureteric stenting was performed as an emergency procedure. Radio isotope renography MAG 3 (mercaptoacetyltriglycine 3) was considered to assess the split function of each kidney and to establish severity and degree of obstruction affected renal collecting system. This will again dictate the surgical decision-making of the affected renal collecting system. MAG3 renogram showed the left kidney was scarred contributing to 1% of overall function. Interval retrograde pyelogram assessment demonstrated extensive mid-ureteral filling defects with proximal gross dilatation of the renal pelvis (figure 2). Ureteroscopic assessment demonstrated widespread soft tissue non-papillary lesions throughout the left collecting system. Biopsy from a mid-ureteral lesion was obtained. On histopathology assessment, nodular ureteric lesions (figure 3) confirmed as ureteric endometriosis with immunostains (GATA3). There were appreciable multilevel endometrial epithelium lining the endometriotic glands (figure 4). The patient consented to definitive surgery in the form of laparoscopic nephroureterectomy due to extensive ureteric involvement and chronically obstructed non-functioning kidney. Outcome/follow-up In our case study following the nephrectomy, there was no further episode of endometriosis or exacerbation, patient remained asymptomatic and has been on regular follow-up with primary care physician. No hormonal replacement therapy was used.

Endometriosis is the presence of endometrial tissue external to the uterine cavity and may affect most parts of the body.1 The prevalence is underestimated as endometriosis is largely insidious, yet 1%–10% of patients with endometriosis may infiltrate the urinary system with a ratio of 40:5:1:1 involving the bladder, ureter (less than 1%), kidneys and urethra, respectively.1 3 4 The left ureter is more frequently implicated than the right side, with 20%–25% bilateral incidence.5 6 Ureteric obstruction secondary to endometriosis is fourfold more likely to be caused by extrinsic compression rather than intrinsic occlusion.4 6 Almost half of patients are asymptomatic, with symptoms more prevalent in intrinsic endometriosis; patients may present with flank or lumbar pain, recurrent UTIs, dysuria, urgency and (cyclic) haematuria.1 5 6 As clinical symptoms may be absent or poorly reflective of severity of disease, this leads to delayed diagnosis and irreversible renal failure.5 A case series done by Peng et al 7 found 92 cases of ureteral endometriosis. However, 88% were symptomatic with hydronephrosis. Basma et al 8 reported surgical treatment for urinary tract endometriosis between 2005 and 2009. A total of 81 women identified to have infiltrating urinary tract endometriosis, 39 isolated bladder endometriosis and 31 isolated ureteral endometriosis and the rest were mixed bladder, ureteral and renal. A total of 50 underwent surgical procedure for bladder endometriosis and 50 different ureteric surgical procedure also reported . Another prospective study by Liliana et al 9 showed 56 patients with clinically suspected ureteral endometriosis either perioperatively or intraoperatively, all underwent corrective urological surgery including two nephrectomy in this cohort. Abdominal ultrasonography is a useful first-line, non-invasive modality to guide definitive imaging.5 6 CT intravenous urography detects level, degree and laterality of disease.6 Otherwise, MRI is a reliable tool in evaluating soft tissue thickening including deep infiltrating endometriotic lesions, in addition to preoperative planning.5 6 Moreover, MR urography accurately differentiates intrinsic from extrinsic disease.6 Direct visualisation is obtained via ureteroscopy for intrinsic endometriosis and laparoscopy for extrinsic disease.6 Subsequently, biopsy is essential for tissue diagnosis.6 This allows evaluation of location, severity and additional foci of endometriosis if any, and excludes malignancy and concomitant pathologies.6 Hormonal treatment is frequently ineffective in extensive disease and risks recurrence, thus laparoscopic or open surgery is often indicated, ranging from ureteroureterostomy, ureteroneocystostomy or nephroureterectomy in severe cases.1–6

Ureteral endometriosis is a rare clinical entity with potentially serious complications. Clinicians should remain vigilant about presentations of obstructive uropathy in the absence of renal calculus in women of reproductive age for timely diagnosis and management to prevent progression into renal failure. Learning points. Intrinsic ureteric obstruction secondary to endometriosis is a rare cause of obstructive uropathy. When investigating obstructive uropathy in women of reproductive age, rare manifestations/aetiology need to be considered. Especially if no obvious obstructive causes are identified, this approach would prompt further investigations without delay to reach a diagnosis and timely treatment. Footnotes Contributors: The following authors were responsible for drafting of the text, sourcing and editing of clinical images, investigation results, drawing original diagrams and algorithms, and critical revision for important intellectual content: PAS, XYG and AL. The following authors gave final approval of the manuscript: SP. Funding: The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors. Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy. Competing interests: None declared. Provenance and peer review: Not commissioned; externally peer reviewed. Ethics statements Patient consent for publication Consent obtained directly from patient(s).

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