Urothelial papilloma

By Jason Wasserman MD PhD FRCPC
June 12, 2025

A urothelial papilloma is a benign (non-cancerous) tumour that develops from cells lining the inside surface of the urinary tract. While it usually forms in the bladder, it can appear anywhere along the urinary tract. After removal, some papillomas may regrow, but importantly, they do not become cancerous over time.

Understanding the urinary tract

The urinary tract is a group of organs that helps your body remove waste and extra water in the form of urine. It includes:

• Kidneys: These filter your blood and produce urine.

• Ureters: Tubes that carry urine from the kidneys to the bladder.

• Bladder: A muscular sac that stores urine until it is ready to leave your body.

• Urethra: The tube through which urine leaves your body.

The lining inside the urinary tract is composed of specialized cells called urothelial cells, which form a protective barrier known as the urothelium.

What are the symptoms of a urothelial papilloma?

The most common symptom of a urothelial papilloma is blood in the urine, which causes the urine to appear pink, red, or brown in colour. Other possible symptoms include:

• Pain or discomfort when urinating.

• The need to urinate more frequently or urgently.

Some papillomas may cause no noticeable symptoms and may be discovered incidentally during medical exams or procedures done for other reasons.

What causes a urothelial papilloma?

Doctors and researchers do not currently know precisely what causes urothelial papillomas to develop. Unlike some other growths in the urinary tract, there are no identified risk factors or known irritants linked specifically to this type of tumour.

What does a urothelial papilloma look like under the microscope?

Under a microscope, a urothelial papilloma consists of normal urothelial cells arranged into long, finger-like growths. Pathologists describe this pattern as “papillary” or “exophytic,” meaning it grows outward from the inner surface of the urinary tract. The cells in a urothelial papilloma resemble healthy urothelial cells, indicating that the tumour is not cancerous.

What is the difference between urothelial papilloma and papillary urothelial carcinoma?

Although the names sound similar, urothelial papilloma and papillary urothelial carcinoma are very different types of tumours:

• A urothelial papilloma is benign (non-cancerous). It rarely recurs after removal and does not spread to other parts of the body.

• Papillary urothelial carcinoma is a malignant (cancerous) tumour. It can return after removal, grow deeper into the tissues, and potentially spread to other parts of the body.

Clearly distinguishing between these two conditions is very important because they require different treatments and follow-up care.

How is a urothelial papilloma diagnosed?

Your doctor may first suspect a urothelial papilloma if they observe a growth during a procedure called cystoscopy. In this procedure, a thin tube with a camera is inserted through the urethra into the bladder to examine its inner surface.

However, a definitive diagnosis of urothelial papilloma can only be made after the tumour is removed. After removal, the tumour tissue is sent to a pathologist, who examines it under the microscope to confirm that it is benign and not cancerous.

How is a urothelial papilloma treated?

The primary treatment for a urothelial papilloma is surgical removal. Typically, doctors remove these growths through a procedure called transurethral resection (TUR), which is performed through the urethra. Once removed, additional treatments such as chemotherapy or radiation therapy are not necessary, since papillomas are benign.

Follow-up care after treatment

Although urothelial papillomas are benign, doctors may recommend periodic follow-up appointments, especially if symptoms recur. Follow-up usually involves urine tests, cystoscopy, or other imaging tests to make sure the tumour has not returned.

Questions to ask your doctor

• How do we know for sure my tumour is a papilloma and not cancer?

• Do I need any further treatment after the tumour is removed?

• What are the chances of this tumour growing back?

• How often should I return for follow-up visits?

• Are there specific symptoms that might mean the tumour has returned?

• Should I make any lifestyle changes or precautions to avoid recurrence?