Could Bladder Endometriosis Explain Your “Mystery” Urinary Pain?

Living with endometriosis or adenomyosis can already feel like you’re constantly proving your pain is real. When bladder symptoms enter the picture—burning, urgency, frequent urination, pelvic pressure—it can become even more confusing, especially if urine cultures are negative or antibiotics don’t help.

Here’s the tricky part: bladder endometriosis (endometriosis affecting the bladder wall) can look “textbook”… or it can look nothing like you’d expect. Some people have classic cyclical urinary symptoms around their period. Others mostly have pelvic pain and almost no urinary symptoms at all. That symptom mismatch is one reason bladder endometriosis can be missed or diagnosed late. Sometimes it is diagnosed at the time of surgery, which is often too late to have the appropriate surgeon(s) present.

Recent clinical evidence (including a 2025 report describing two very different real-world presentations) reinforces a practical message for patients: if symptoms keep returning, especially with any cycle pattern, it’s worth asking about pelvic imaging—often including MRI—to check the bladder and nearby structures.

What bladder endometriosis can feel like (and why it’s missed)

Bladder endometriosis is considered a type of deep infiltrating endometriosis (DIE). It typically involves the bladder muscle wall (muscularis) rather than just the surface (serosa) or the internal lining (mucosa). That matters because deeper disease is more likely to cause persistent symptoms and may not respond well to “wait and see.”

Common symptom patterns include:

• Cyclical urinary urgency/frequency, burning, pain with bladder filling, or pain when you pee—often flaring before or during your period
• Pelvic pain that feels “bladder-adjacent” (low, central pelvic pain or pressure)
• Pain with sex, especially deep penetration (because bladder endo can coexist with other DIE locations)
• Blood in the urine (hematuria)—this can happen, but it’s not required and it’s not a standalone diagnostic test

A major reason bladder endometriosis is overlooked: these symptoms overlap with UTIs, interstitial cystitis/bladder pain syndrome, pelvic floor dysfunction, ovarian cysts, adenomyosis, IBS, and more. If you’re told “your urine is clear, so it can’t be your bladder,” you’re not alone—and that statement isn’t reliably true.

When to suspect bladder endometriosis

You don’t need every symptom to justify looking deeper. Bladder endometriosis, especially deep invasion (DIE) is uncommon, but not rare. It becomes more plausible when there’s a pattern—especially a cycle-linked pattern—or when common explanations don’t fit.

A reasonable “raise your hand and ask” moment is when:

• You have recurrent urinary symptoms with negative cultures
• Symptoms worsen predictably around your period
• You have known endometriosis/DIE elsewhere (or strong suspicion)
• You have persistent pelvic pain and nothing else explains it well
• You’ve been treated repeatedly for UTIs without lasting relief

Even if your urinary symptoms are minimal, pelvic pain alone doesn’t rule bladder endometriosis out. Some patients have bladder lesions discovered because imaging was done for pelvic pain rather than urinary complaints.

What testing can actually help (and what each test can and can’t do)

Urine testing

Urinalysis can sometimes show microscopic blood. That can be a clue, but it is not specific—many conditions can cause it, and bladder endometriosis can exist without it. Think of urine testing as part of the puzzle, not the answer.

Ultrasound

Pelvic ultrasound may detect a bladder wall lesion in some cases, but it can miss deep disease or underestimate its extent. It’s often a first-line test, not the final word.

MRI (often the turning point)

For many patients, pelvic MRI is the imaging test that most helps:

• Identify a bladder wall lesion suspicious for deep endometriosis
• Map how deep it goes and how close it is to critical structures
• Clarify whether the lesion is near the ureteral orifice (where the ureters, which brings urine from the kidneys, drain into the bladder). There is one on both sides.

That last point is not just “nice to know.” If a lesion involves or threatens the ureter, it can affect surgical planning and—rarely—kidney drainage.

Important reality check: MRI is powerful, but it’s not perfect. The fact that MRI worked well in two recent cases does not mean MRI always detects bladder endometriosis. It does mean MRI is worth discussing when symptoms persist and the clinical picture isn’t adding up.

Cystoscopy (looking inside the bladder)

Some clinicians use cystoscopy to evaluate the inside lining of the bladder. But bladder endometriosis can be deep within the wall and may not always create a clear visible lesion inside the bladder. It can help in some situations, but it isn’t automatically definitive.

The final confirmation: pathology

Even when imaging is strongly suggestive, histopathology after surgical removal/biopsy is typically what confirms bladder endometriosis.

Treatment options that actually matter to your daily life

1) Hormonal suppression (symptom control, not a “cure”)

Hormonal treatments can reduce endometriosis activity and pain for many patients. Options often include:

• Progestogens (including progestins like dienogest or natural progesterone)
• Combined hormonal contraception (pill/patch/ring)
• GnRH agonists (GnRH-a) or antagonists (with add-back therapy in many cases)

In the 2025 case-based evidence, a postoperative plan of GnRH-a for 6 months followed by dienogest was used, with good short-term symptom relief and no recurrence reported during the limited follow-up. That’s encouraging, but you should interpret it carefully: two patients and short follow-up can’t prove recurrence prevention for general use. Also, keep in mind that GnRH-a bear substantial risk and treatment should be highly individualized.

For you, the practical question is: can hormonal suppression make you functional with acceptable side effects? If yes, it may be a reasonable non-surgical approach or an add-on after surgery.

2) Surgery (when deeper bladder wall disease is driving symptoms)

If bladder endometriosis is deep in the bladder wall, especially if it’s large, persistent, or threatening the ureter, surgery may be discussed as the more definitive option.

One commonly used approach for deep bladder lesions is laparoscopic or robotic partial cystectomy (removing the diseased portion of bladder wall and repairing the bladder). In the recent case-based evidence, this was feasible in both patients and symptoms improved in the short term. In one case, the lesion was close enough to the ureteral opening that ureteral reimplantation was needed (rerouting the ureter into the wall of the bladder in another location).

That can sound terrifying—so here’s the patient-centered translation: if imaging suggests the lesion is near the ureter, you want a surgeon/team that can plan for this and protect kidney drainage. It doesn’t mean you will need ureter surgery; it means the surgical skill set and planning matter.

How long before you know a plan is working?

Timeline depends on the approach:

• With hormonal suppression, many people look for meaningful symptom change within the first 2–3 months, with continued improvement over 6 months (though side effects can appear earlier).
• After bladder surgery, early recovery is measured in weeks, but “settling” of pelvic pain and urinary irritation can take longer. Your team should give you a concrete plan for catheter time (if used), activity limits, and follow-up.

If your symptoms aren’t improving on a timeline your clinician considers reasonable, that’s not you “failing treatment.” It’s information—your plan may need adjusting.

Practical takeaways: what to ask your doctor

• “Given my symptoms and cycle pattern, could this be bladder endometriosis or deep infiltrating endometriosis?”
• “Should I get pelvic MRI to evaluate the bladder wall and how close anything is to the ureters?”
• “If imaging shows a bladder lesion, who would perform surgery—and do they have experience with partial cystectomy and managing lesions near the ureter?”
• “If we use hormones, what’s the goal—symptom control, shrinking disease before surgery, or suppression after surgery?”
• “What side effects should I watch for, and what would make you switch medications?”

Reality check (so you can make grounded decisions)

Bladder endometriosis can be “straightforward” when symptoms and imaging line up—but many patients don’t present neatly. Atypical symptoms are real. So is diagnostic delay.

Also, while postoperative hormonal suppression (like GnRH-a followed by dienogest) may help some people, we don’t have strong proof from small case reports that it prevents long-term recurrence. Your best plan depends on your goals (pain control, fertility, avoiding repeat surgeries), other disease locations, and your tolerance for hormonal side effects. The best strategy, if surgery is part of the plan, is to have a surgeon like an endo-informed gynecologic oncologist or a team which includes a urologist alongside your gyn endo excision surgeon.

If you’re stuck in a loop of “UTI treatment → negative tests → ongoing pain,” you deserve a more complete evaluation. Bladder endometriosis, especially DIE, is uncommon—but it’s not rare enough to ignore when the story fits.