Urinary Tract Metastases
Urinary tract metastases refer to cancers that have spread (metastasized) to parts of the urinary system—such as the kidneys, ureters, bladder, or urethra—from tumors that began elsewhere in the body. These metastatic deposits are uncommon but may occur with cancers such as melanoma, breast cancer, lung cancer, stomach cancer, or lymphoma. Findings are often subtle, and many cases are discovered incidentally on imaging performed for cancer staging or follow-up.
What is it?
Urinary tract metastases occur when cancer cells spread through the bloodstream or lymphatic system from another organ to the kidneys, ureters, bladder, or urethra. Kidney metastases are more common than ureter or bladder metastases, but all can occur. These lesions may appear as small masses, wall thickening, or obstructing abnormalities depending on the location and type of cancer.
Imaging—especially CT or MRI—helps detect metastatic lesions and assess their impact on urinary drainage. Ultrasound may identify kidney lesions but is less sensitive for ureters or bladder involvement. Additional tests such as cystoscopy may be needed if bladder lesions are suspected.
Important to Know
Urinary tract metastases indicate advanced disease and require coordinated care between oncology and urology teams. Treatment focuses on controlling the primary cancer and addressing symptoms such as obstruction or bleeding. Some metastatic lesions may cause hydronephrosis (kidney swelling) or urinary symptoms if they block urine flow.
Red flag symptoms include visible blood in the urine, new flank pain, sudden difficulty urinating, recurrent urinary infections, or unexplained weight loss. These symptoms may indicate obstruction or active disease requiring urgent evaluation.