A cyst is a sac-like pocket of membranous tissue filled with fluid, pus, air, or other substances. Cysts can grow practically anywhere in your body. Cysts that form inside the lining of the urinary bladder, the hollow organ where urine collects before it’s eliminated from the body, are very rare in those with an otherwise normal urinary tract.
When a cyst or a group of cysts form inside the bladder, they’re usually benign and not cancerous. However, some bladder cysts may be associated with having a higher risk of developing bladder cancer in the future.
Cysts vs. polyps
Cysts aren’t the same as polyps and tumors, which are different types of abnormal growths of tissue. Like cysts, certain polyps and tumors can be either benign or cancerous.
Your doctor can help determine if the growth is a cyst by performing imaging such as an ultrasound, for example, and then doing a biopsy to determine its content. This involves taking a sample of tissue and looking at it more closely under a microscope. Most bladder cysts don’t require surgical treatment.
Bladder cysts usually don’t cause symptoms unless the cyst is very large or associated with an underlying condition. If they do cause symptoms, they may include:
- pain when you urinate
- pain in your middle pelvic or flank region(s)
- blood in the urine
- frequent urination
- an urgent need to urinate
- foul-smelling urine
- urine incontinence
These symptoms can be very similar to those that occur in other conditions, such as:
- a urinary tract infection (UTI)
- kidney or bladder stones
- a benign prostatic growth
- bladder cancer (rare)
This is why a bladder cyst isn’t diagnosed by your symptoms alone.
Doctors don’t always know exactly why bladder cysts form. Some cysts are thought to occur due to chronic inflammation in the bladder.
You may be at a higher risk of having a bladder cyst if you:
- have frequent UTIs
- have a history of bladder or kidney stones
- use a catheter
- have had surgery on or near the bladder
A rare condition known as cystitis cystica results in the formation of multiple benign cysts in the bladder. Cystitis cystica is more common in women. It’s thought to be the result of chronic irritation in the urinary tract causing inflammation in the bladder.
Your doctor will take a detailed medical history and ask you questions about your symptoms. They may ask you to urinate inside a cup so your urine can be tested for things like bacteria that cause infections. Typically, a urinalysis is first done for screening to see if your urine has any abnormal features. If infection is suspected, more specific testing, called a urine culture, is then performed on your urine.
If your doctor suspects you have a cyst inside your bladder, they may refer you to a urologist. A urologist is a doctor who specializes in issues with the urinary tract. The urologist will likely run further diagnostic studies to rule out other types of bladder lesions or conditions. Imaging tests might be used to help your doctor see your bladder. These may include one or more of the following:
- plain film X-ray
- CT scan, which typically uses a stronger dose of X-rays (compared to plain film X-ray) to create more detailed cross-sectional images
- ultrasound, which doesn’t involve radiation, uses sound waves to create pictures of the organs
- MRI scan, which also doesn’t involve radiation, uses a magnetic field and radiofrequency waves to create detailed images of soft tissues in the body
If tests reveal a mass inside your bladder, it’s likely that a urologist will want to perform a cystoscopy and bladder biopsy procedure to look inside your bladder and to find out if the mass contains cancer cells.
During a cystoscopy, your doctor inserts a thin tube with a small camera (cystoscope) through the urethra and into your bladder. During the biopsy, your doctor will take a sample of tissue to be looked at more closely under a microscope.
Bladder cysts might also be discovered during a diagnostic procedure for an unrelated condition. For example, a doctor might notice that you have cysts in your bladder during an evaluation for hip replacement surgery.
Usually bladder cysts don’t cause any problems. However, they can sometimes lead to complications, including:
- infection in the cyst
- urinary obstruction (blockage)
Most cysts inside the bladder don’t cause problems and don’t require any treatment. If the cyst is causing severe symptoms, or if it ruptures or becomes infected, it may be removed by surgery.
If your doctor believes your cysts were related to urinary tract infections or urinary tract stones, you’ll also receive treatment for those conditions.
Bladder cysts are usually benign lesions in the bladder. If you have a bladder cyst, that doesn’t mean you have cancer. Most bladder cysts don’t cause any symptoms and won’t require any treatment.
Your doctor will want to monitor your cyst(s) over time because if you have a bladder cyst, you may be at a higher risk of developing bladder cancer in the future. If you have any of the symptoms of bladder cysts, or if you experience recurrent urinary tract infections, see your doctor for an evaluation.