What is cancer of the renal pelvis or ureter?

Cancer of the renal pelvis or ureter starts in the cells of the renal pelvis (a hollow part of each kidney) or ureter (a tube that connects each kidney to the bladder). A cancerous (malignant) tumour is a group of cancer cells that can grow into nearby tissue and destroy it. The tumour can also spread (metastasize) to other parts of the body.

Diagram of the location of the kidneys and ureters
Diagram of the location of the kidneys and ureters

Cells in the renal pelvis or ureter sometimes change and no longer grow or behave normally. In some cases, changes to these cells can cause cancer. Most often, cancer starts in urothelial cells that line the inside of the renal pelvis or ureter. This type of cancer is called urothelial carcinoma (also called transitional cell carcinoma). It makes up about 90% of all upper urinary tract tumours. Urothelial carcinoma starts in the renal pelvis more often than the ureter, but it can also be found in both places at the same time.

Rare types of renal pelvis and ureter cancer can also develop. These include squamous cell carcinoma and adenocarcinoma of the renal pelvis or ureter.

The renal pelvis and ureter

The renal pelvis and ureter are part of the urinary system and make up the upper urinary tract. The renal pelvis is a hollow part in the middle of each kidney. The ureters are thin tubes that connect the kidneys to the bladder. Each ureter is about 25 to 30 cm (10 to 12 inches) long.

Urine (pee) is your body’s liquid waste and is made by the kidneys. It collects in the renal pelvis then travels along the ureters to the bladder where it is stored. When the bladder is full of urine, it passes out of the body through the urethra.

Diagram of inside the kidney
Diagram of inside the kidney

Layers of the renal pelvis and ureter

The walls of each renal pelvis and ureter are made up of 3 main layers of tissue.

The urothelium is the inner lining of each renal pelvis and ureter. It continues as the lining for the bladder and urethra. It is made up of urothelial cells (also called transitional cells), which can stretch and change shape as urine flows. The urothelium is also called the transitional epithelium.

The lamina propria is a thin layer of connective tissue that surrounds the urothelium of each renal pelvis and ureter. It contains blood vessels, nerves and glands.

The muscularis propria is a thick, outer muscle layer of each renal pelvis and ureter. It is made up of muscle that works automatically without you thinking about it (called smooth muscle). It pushes urine from the kidney down to the bladder.

Other tissues that surround the kidneys and ureters are:

  • adventitia – loose connective tissue that covers the kidneys and ureters
  • fat – a layer of fat that surrounds the renal pelvis, kidney and ureter

Expert review and references

Cancerous tumours of the renal pelvis and ureter

Urothelial carcinoma (also called transitional cell carcinoma) is a cancerous tumour of the renal pelvis and ureter that can spread (metastasize) to other parts of the body. Cancerous tumours are also called malignant tumours.

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