Kidney tumors are abnormal growths of cells in the kidney. They can be benign (non-cancerous) or malignant (cancerous). Kidney tumors are relatively rare, accounting for only about 2% of all adult cancers.

Most kidney tumors are found incidentally when a person has an imaging test (such as a CT scan or MRI) for another reason. However, some people with kidney tumors may have symptoms, such as blood in the urine or a mass in the abdomen.

If a kidney tumor is found, additional testing will be needed to determine if it is benign or malignant. This may involve needle biopsy, in which a small sample of tissue is removed for examination under a microscope. If the tumor is determined to be cancerous, surgery will be necessary to remove it. In some cases, chemotherapy or radiation therapy may also be used.