Bladder Endometriosis: A Systematic Review of Pathogenesis, Diagnosis, Treatment, Impact on Fertility, and Risk of Malignant Transformation

CONTEXT: The bladder is the most common site affected in urinary tract endometriosis. There is controversy regarding the pathogenesis, clinical management (diagnosis and treatment), impact on fertility, and risk of malignant transformation of bladder endometriosis (BE). OBJECTIVE: To systematically evaluate evidence regarding the pathogenesis, diagnosis, medical and surgical treatment, impact on female fertility, and risk of malignant transformation of BE. EVIDENCE ACQUISITION: A systematic review of PubMed/Medline from inception until October 2016 was performed in accordance with the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement and was registered in the PROSPERO registry (www.crd.york.ac.uk/prospero; CRD42016039281). Eighty-seven articles were selected for inclusion in this analysis. EVIDENCE SYNTHESIS: BE is defined as the presence of endometrial glands and stroma in the detrusor muscle. Ultrasonography is the first-line technique for assessment of BE owing to its accuracy, safety, and cost. Clinical management can be conservative, using hormonal therapies, or surgical. When conservative treatment is preferred, estrogen-progestogen combinations and progestogens should be chosen because of their favorable profile that allows long-term therapy. Surgery should guarantee complete removal of the bladder nodule to minimize recurrence, so transurethral surgery alone should be avoided in favor of segmental bladder resection. There is not a strong rationale for hypothesizing a detrimental impact of BE per se on fertility. Furthermore, current evidence does not support the removal of bladder endometriotic lesions because of the potential risk of malignant transformation since this phenomenon is exceedingly rare. CONCLUSIONS: BE is a challenging condition, and the common coexistence of other types of endometriosis means that clinical management of BE should involve collaboration between gynecologists and urologists. PATIENT SUMMARY: In this article we review available knowledge on bladder endometriosis. The review provides a useful tool to guide physicians in the management of this complex condition.