Bladder endometriosis: a current overview of pathogenesis, diagnosis, and treatment approaches

Endometriosis is a chronic inflammatory disease affecting approximately 10% of women of reproductive age. Urinary tract involvement is rare, occurring in approximately 1–2% of cases, with the bladder being the most frequently affected organ. Bladder endometriosis is often associated with deep infiltrative endometriosis and can lead to delays in diagnosis due to non-specific symptoms. In recent years, advances in magnetic resonance imaging (MRI) techniques have increased diagnostic accuracy, and minimally invasive surgical methods have come to the forefront in treatment. This review pres - ents the pathogenesis, clinical features, diagnostic approaches, and current treatment options of bladder endometriosis, along with a review of the literature.

Bladder endometriosis · Deep infiltrating endometriosis · MRI · Cyclic hematuria Received: 30 March 2026 / Accepted: 16 June 2026 © The Author(s) 2026 Bladder endometriosis: a current overview of pathogenesis, diagnosis, and treatment approaches Belma Gözde Özdemir1  · Halis Özdemir2 Pathogenesis and etiology The pathogenesis of endometriosis is multifactorial, with the most widely accepted theory being retrograde menstrua- tion [5]. According to this theory, endometrial cells migrate to the peritoneal cavity and implant there. However, theo - ries of coelomic metaplasia and lymphatic/hematogenous spread are also important in explaining the development of the disease [ 6]. In bladder endometriosis, the most likely mechanism is considered to be direct invasion from the anterior wall of the uterus into the bladder. Iatrogenic implantation may also play a role in patients with a history of uterine surgery [7]. Clinical findings Bladder endometriosis is generally characterized by cyclic urinary symptoms. The most common findings are dysuria, pollakiuria, and suprapubic pain. Menstruation-related hematuria is a highly specific finding for the disease and provides an important clue in diagnosis. However, its absence in all patients can make diagnosis difficult.

Endometriosis is a chronic, estrogen-dependent inflamma - tory disease characterized by the extrauterine localization of the endometrial gland and stroma [1]. It is estimated to affect approximately 10% of women of reproductive age. While the disease most commonly involves the ovaries and pelvic peritoneum, extrapelvic locations have also been described [2]. Urinary system endometriosis is a rare clinical entity, accounting for approximately 1–2% of all cases [3]. Bladder involvement is present in 70–85% of these cases [ 4]. Blad- der endometriosis is frequently included within the deep infiltrative endometriosis spectrum and can lead to serious lower urinary tract symptoms. Diagnostic delay is a signifi- cant clinical problem, reported to be between 4 and 7 years on average. In recent years, advances in MRI techniques have increased diagnostic accuracy, and minimally invasive surgical approaches have come to the forefront of treatment. 1 3 Abdominal Radiology Diagnosis The diagnosis of bladder endometriosis is made by a com - bination of clinical suspicion, imaging methods, and histo - pathological confirmation. The most important step in the diagnostic process is carefully questioning the presence of cyclic symptoms. The presence of dysuria, pollakiuria, or hematuria, especially related to menstruation, provides a strong clinical clue for diagnosis. However, diagnosis is often delayed because the symptoms are non-specific and can overlap with many diseases. Physical examination find- ings are often limited, but tenderness in the anterior com - partment or the presence of nodular structures on bimanual examination may suggest deep infiltrative endometriosis. However, advanced imaging methods are needed to reach a definitive diagnosis. Imaging methods Ultrasonography is generally the first-line method, but it has limited sensitivity [8]. Transvaginal ultrasonography, espe- cially in experienced hands, can be useful in detecting ante- rior compartment lesions; however, it may be insufficient for evaluating small lesions showing deep invasion of the bladder wall. Furthermore, operator dependence is one of the significant limitations of ultrasonography. Magnetic resonance imaging (MRI) is considered the gold standard imaging modality for the evaluation of blad - der endometriosis, particularly in patients with deep infiltrat- ing endometriosis. A dedicated pelvic MRI protocol should include high-resolution T2-weighted sequences in sagit - tal, axial, and coronal planes, fat-suppressed T1-weighted imaging, and diffusion-weighted imaging (DWI) [ 9, 10]. MRI accurately demonstrates lesion localization, size, depth of bladder wall invasion, and relationships with adjacent pelvic structures. Typical findings include T2-hypointense nodules reflecting fibrosis and smooth muscle hyperplasia, together with T1-hyperintense foci corresponding to hem - orrhagic implants. These imaging characteristics are highly suggestive of endometriosis and help differentiate the dis - ease from urothelial carcinoma. Furthermore, MRI plays a crucial role in preoperative planning by assessing detrusor muscle involvement, proximity to the ureteral orifices, and the extent of associated pelvic endometriosis, thereby guid- ing surgical management and reducing intraoperative com - plications (Fig. 1). Medical treatment Medical treatment options include GnRH agonists, oral con- traceptives, and progestins [11]. These agents aim to reduce the activity of endometriotic foci and control symptoms by suppressing estrogen production. Oral contraceptives and progestins are generally preferred as first-line treatment and can be effective, especially in patients with mild symptoms. GnRH agonists can provide stronger hormonal suppres - sion but their long-term use is limited by hypoestrogenic side effects. However, medical treatment generally does not eradicate the disease, and symptoms may recur after treat - ment discontinuation. Therefore, medical therapy is mainly reserved for patients with mild disease, those who are poor surgical candidates, or as adjunctive treatment before surgery. Surgical treatment The management of bladder endometriosis should be indi - vidualized based on symptom severity, lesion size and depth, extent of disease, and patient-specific factors such as age, fertility desire, and comorbidities. While surgical excision remains an important and often definitive treatment option, particularly in cases of deep infiltrating disease involving the detrusor muscle or in patients with refractory symptoms, it should not be considered universally as the “gold stan - dard” for all patients. Instead, a tailored approach that inte - grates both medical and surgical strategies is recommended. Medical treatment aims to suppress ovarian function and reduce the activity of endometriotic lesions, thereby alle - viating symptoms and potentially delaying disease pro - gression. Commonly used agents include combined oral contraceptives and progestins; among these, dienogest has demonstrated significant efficacy in pain control and lesion stabilization. The levonorgestrel-releasing intrauterine system (LNG-IUS) also represents an effective long-term option, particularly in patients seeking fertility preserva - tion or wishing to avoid systemic side effects. In addition, newer oral GnRH antagonists, such as elagolix and relu - golix, have emerged as valuable alternatives by providing rapid and reversible suppression of gonadotropin secretion with a more favorable side-effect profile compared to GnRH agonists. These agents allow dose-dependent modulation of estrogen levels and are increasingly incorporated into mod- ern endometriosis management algorithms. Surgical inter - vention, including partial cystectomy, is generally reserved for patients with severe symptoms, bladder wall invasion, ureteral involvement, or failure of medical therapy. There - fore, optimal management requires a multidisciplinary and 1 3 Abdominal Radiology patient-centered approach, balancing symptom control, dis- ease progression, and reproductive goals. Surgical treatment remains the preferred definitive treat- ment for patients with deep infiltrating bladder endometrio- sis, severe symptoms, or failure of medical therapy [ 12]. The main goal of surgery is to eliminate symptoms and minimize the risk of recurrence by achieving complete exci- sion of the lesions. Partial cystectomy is the most effective

for removing lesions that invade the bladder wall. This procedure can be performed laparoscopically or with robotic surgery. Complete excision is critical in reducing the risk of recurrence [13, 14]. In the case of incomplete resec- tion, both the continuation of symptoms and the progression of the disease may occur. While the laparoscopic approach offers the advantages of minimally invasive surgery, robotic surgery provides better visibility, precise dissection, and ergonomic ease [ 15]. During surgical planning, the depth of the lesion in the bladder wall, its proximity to the ure - ters, and accompanying pelvic endometriosis foci should be considered. A multidisciplinary approach (collaboration between urology and gynecology) plays an important role in increasing surgical success in complex cases. Differential diagnosis The differential diagnosis of bladder endometriosis is clini- cally and radiologically important, given the overlap of symptoms with other bladder pathologies. Urothelial car - cinoma represents the most critical condition to exclude, as it typically presents with painless hematuria and appears on imaging as an irregular, enhancing mass with predominant mucosal involvement, in contrast to the usually well-cir - cumscribed, submucosal or intramural lesions seen in endo- metriosis. Interstitial cystitis/bladder pain syndrome should also be considered, particularly in patients presenting with chronic pelvic pain and urinary frequency; however, imag - ing findings are typically absent or nonspecific, and diag - nosis relies mainly on clinical criteria and cystoscopic evaluation. Urachal pathology, including urachal remnants or neoplasms, may mimic bladder dome lesions but are usu- ally located in the midline along the urachal tract and may show cystic or mixed solid-cystic characteristics on imag - ing. In contrast, bladder endometriosis is often associated with cyclical symptoms, characteristic MRI features such as T2-hypointense fibrotic nodules and T1-hyperintense Fig. 1 MRI appearance of bladder endometriosis. A Axial T2-weighted image demonstrating a hypointense nodule in the posterior bladder wall (arrow), consistent with fibrosis and smooth muscle hyperplasia. B Sagittal T2-weighted image showing infiltration of the detrusor mus- cle by the lesion (arrow). C Axial fat-suppressed T1-weighted image revealing hyperintense hemorrhagic foci within the lesion (arrow). D Diffusion-weighted image demonstrating restricted diffusion within the lesion (arrow), supporting deep infiltrative disease. These imaging findings are characteristic of bladder endometriosis and are useful for diagnosis, differential diagnosis, and preoperative assessment 1 3 Abdominal Radiology hemorrhagic foci, and coexistence with other deep infil - trating endometriosis lesions. Therefore, integrating clini - cal history with advanced imaging findings is essential for accurate diagnosis and appropriate management. Cystoscopy plays a complementary role in the diagnos - tic work-up by allowing direct visualization of the bladder mucosa. In cases of bladder endometriosis with mucosal involvement, cystoscopy may reveal characteristic bluish or reddish nodules, hyperemic areas, or polypoid lesions; however, it may also be normal when the disease is confined to the serosal or muscular layers. Therefore, negative cys - toscopic findings do not exclude the diagnosis. Moreover, cystoscopy is particularly useful in differentiating endome - triosis from urothelial carcinoma, as malignant lesions typi- cally present as irregular, friable masses with a tendency to bleed. When suspicious lesions are identified, biopsy during cystoscopy remains essential for histopathological confir - mation and definitive diagnosis. Consequently, the integra - tion of clinical presentation, MRI findings, and cystoscopic evaluation is crucial for accurate diagnosis and appropriate management. Prognosis and recurrence Post-surgical prognosis is generally good, and significant improvement in symptoms is achieved in the vast majority of patients. However, recurrence rates are directly related to whether surgical excision is complete or not [16]. In the case of incomplete excision, the presence of residual disease is a significant risk factor for recurrence. In addition, multifocal disease and the presence of accompanying deep infiltrative endometriosis foci can also increase the risk of recurrence. Therefore, long-term follow-up of patients and planning of additional treatment when necessary are important. Current discussions and future perspectives The optimal approach between medical and surgical treat - ment in the management of bladder endometriosis is still debated. While medical treatment provides symptom con - trol, surgical treatment offers more permanent results. How- ever, there is no standard approach for every patient, and treatment should be individualized. The increasing use of robotic surgery has the potential to improve surgical out - comes. However, more studies are needed on the cost- effectiveness and long-term results of these techniques. In the future, the development of biomarkers that enable early diagnosis and further advancements in imaging techniques will play a significant role in disease management. Fur - thermore, the widespread adoption of a multidisciplinary approach will improve treatment success, especially in com- plex cases.

Bladder endometriosis is a rare but clinically significant disease. The presence of cyclic hematuria is an important diagnostic clue and should be carefully evaluated. Magnetic resonance imaging plays a crucial role in diagnosis, while surgical excision forms the basis of treatment. Early diagno- sis, appropriate treatment selection, and a multidisciplinary approach can significantly improve patients’ quality of life.

None. Author contributions BGÖ: Developing the concept and design of the study, conducting a literature review, analyzing data, and writing the article draft.HÖ: Contributing to the design of the study, making criti- cal revisions, and approving the final version of the article.All authors have read and approved the final version of the article. Funding Open access funding provided by the Scientific and Techno- logical Research Council of Türkiye (TÜBİTAK). None. Data availability No datasets were generated or analysed during the current study. Declarations Conflict of interest The authors declare no competing interests. Ethical approval This is a study that does not require ethical approval. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit h t t p : / / c r e a t i v e c o m m o n s . o r g / l i c e n s e s / b y / 4 . 0 / .

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