A Rare Case of Bladder Endometriosis Mimicking a Bladder Tumor

The presence of endometrial stroma and/or glandular epithelium in organs other than the uterus is called endometriosis. Urinary system endometriosis is observed in approximately 1% of women with endometriosis and is most commonly seen in the bladder. A 27-year-old female patient was admitted to the urology clinic with cyclic complaints of painful and frequent urination. Ultrasonography revealed a lesion extending to the lumen of approximately 15x10 mm in the left side wall of the bladder. On cystoscopy, a suspicious area with irregular borders was observed, approximately 15 mm, at the left-posterior lateral wall of the bladder, and transurethral resection was performed. The pathological result of the patient was reported as bladder endometriosis. Although rare, bladder endometriosis should be considered in the differential diagnosis, especially in women of reproductive age with cyclic urological complaints.

The presence of endometrial stroma and/or glandular epithelium in organs other than the uterus is called endometriosis. Endometriosis rarely occurs in extragonadal organs, such as the bladder and intestinal tract, causing organ-specific symptoms (1). From studies conducted in Europe, urinary system endometriosis was observed in 0.3-12% of women with endometriosis (2,3). The incidence of urinary system endometriosis is as follows: 85% bladder, 9% ureter, 4% kidney, 2% urethra (4). Bladder endometriosis (BE) is defined by the presence of endometriotic tissue in the detrusor muscle of the bladder (5) and is most commonly seen in the bladder base and bladder dome (6). Typically, women with BE present with dysuria, frequency, hematuria, and urinary incontinence (7,8). Anamnesis and imaging methods are important in the diagnosis of BE. The differential diagnosis includes intraluminal bladder lesions, urinary tract infection, urinary tract stone, and interstitial cystitis (9). The aim of BE treatment is to relieve symptoms and prevent possible kidney damage. Treatment can be conservative, medical, or surgical by evaluating the patient and the extent of endometriosis. Case Presentation A 27-year-old female patient was admitted to the urology clinic with complaints of painful urination and frequent urination, which started every month with her menstrual periodfor approximately 1 year. There was no disease or operation history in the medical history. In terms of gynecological history, she had 3 pregnancies, 2 deliveries, and 1 abortion. No erythrocyturia or leukocyturia was observed during complete urinalysis. Ultrasonography revealeda lesion extending to the lumen of approximately 15x10 mm in the left side wall of the bladder. On cystoscopy, a suspicious area with irregular borders was observed, approximately 15 mm, at the left-posterior lateral wall of the bladder, and transurethral resection (TUR) was performed (Video 1). During the resection, brown gelatinous material was observed (Figure 1). The pathology result of the patient was reported as BE (Figure 2-4). No pathology was found in the gynecological evaluation of the patient. The case was evaluated as primary BE. A gonadotropin-releasing hormone (GnRH) analog was started as additional treatment. The patient did not have any symptoms during the 3-month follow-up after surgery. The follow-up of the patient continues.

BE is observed in women of reproductive age and usually around 35 years of age. While the cases that are accepted as primary are found at a rate of 11%, secondary cases are mostly detected because of a reason such as cesarean section or previous pelvic surgery. The frequency of involvement of endometriosis in the urinary system is 85% in the bladder, 9% in the ureter, 4% in the kidney, and 2% in the urethra (4). Patients with BE present to the clinic with dysuria, frequent urination, bladder pain, and less frequent hematuria, urgency, and urinary incontinence (7,8). Dysuria has been reported in 21-69% of patients. Hematuria is a less frequent symptom reported in 0-35% of cases and occurs when the bladder lesion infiltrates the mucosa. Although ultrasonography is the first choice at diagnosis, magnetic resonance imaging may be helpful, especially in cases with suspected ureteral involvement (1). In patients who are scheduled for cystoscopy, it would be more appropriate to evaluate the lesions by considering the menstrual cycle (10). Treatment should be planned by considering the patient’s age, pregnancy desire, and the spread of the disease. Medical treatment of BE reduces symptoms and is used palliatively. Postmenopausal women with a single bladder lesion 5 mm are ideal candidates for medical treatment. The most commonly used drugs are GnRH agonists and antagonists, progestins, and combined oral contraceptives (10). The aim of surgical treatment is the complete removal of the endometrial tissue, and it is the only cure method for BE (10). Surgical treatment options include TUR of the bladder, partial cystectomy, and total cystectomy. If possible, the recommended treatment is complete resection with transurethral surgery (11). A combination of TUR-M and hormone therapy may be preferred in young patients who want to preserve fertility (10). In cases where endometriosis invades the urothelial mucosa from the outside of the bladder, TUR-M treatment is not sufficient and partial cystectomy should be considered (12). Follow-up is recommended for women with deep (e.g. bladder) and ovarian endometriosis, but there is no set follow-up program in the guidelines. The frequency and type of follow-up should be evaluated according to the severity of the disease and symptoms (13).

Although rare, BE should be considered in the differential diagnosis, especially in women of reproductive age who have pelvic pain in the cyclical cycle and a mass in the bladder. Video 1. https://youtu.be/ih1oBnoksvQ