The lack of symptoms makes the early diagnosis of ureteral endometriosis difficult. As with all types of endometriosis, histologic evaluation of a biopsy sample is diagnostic. Multiple imaging modalities have been used to preoperatively diagnose ureteral involvement, including computed tomography,13 magnetic resonance imaging (MRI),14 intravenous pyelogram (IVP), and pelvic ultrasonography. However, each of these imaging modalities is limited in both sensitivity and the ability to characterize depth of tissue invasion.
In a study of 245 women undergoing pelvic ultrasonography, Pateman and colleagues reported that an experienced sonographer was able to visualize the bilateral ureters in 93% of cases.15 Renal ultrasonography is indicated in any woman suspected of having genitourinary tract involvement with the degree of hydroureter and level of obstruction noted during the exam.16
In our group, we perform renography to assess kidney function when hydroureter is noted preoperatively. Studies suggest that if greater than 10% of normal glomerular filtration rate remains, the kidney is considered salvageable, and near-normal function often returns following resection of disease. If preoperative kidney function is noted to be less than 10%, consultation with a nephrologist for possible nephrectomy is warranted.
We find that IVP is often helpful for preoperatively identifying the level and degree of ureteral involvement, and it also can be used postoperatively to evaluate for ureteral continuity (FIGURE 1). Sillou and colleagues showed MRI to be adequately sensitive for the detection of intrinsic ureteral endometriosis, but they reported that MRI often overestimates the frequency of disease.17 Authors of a 2016 Cochrane review of imaging modalities for endometriosis, including 4,807 women in 49 studies, reported that no imaging test was superior to surgery for diagnosing endometriosis.18 However, the review notably excluded genitourinary tract endometriosis, as surgery is not an acceptable reference standard, given that many surgeons cannot reliably identify such lesions.18
Bladder endometriosis. Unlike patients with ureteral endometriosis, those with bladder endometriosis are typically symptomatic and experience dysuria, hematuria, urinary frequency, and suprapubic tenderness.7,19 Urinary tract infection, interstitial cystitis, and cancer must be considered in the differential diagnosis. Urinalysis and urine culture should be performed, and other diagnostic procedures such as ultrasonography, MRI, and cystoscopy should be considered to evaluate for endometriosis of the bladder.
Ultrasound and MRI of the bladder both demonstrate a high specificity for detecting bladder endometriosis, but they lack sensitivity for lesions less than 3 cm.20 Deep infiltrating endometriosis of the bladder can be identified at the time of cystoscopy, which can assist in determining the need for ureteroneocystostomy if lesions are within 2 cm of the urethral opening.20 Cystoscopy also allows for biopsy to be performed if underlying malignancy is of concern.19
In our group, when bladder endometriosis is suspected, we routinely perform preoperative bladder ultrasonography to identify the lesion and plan to perform intraoperative cystoscopy at the time of laparoscopic resection.19,21
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