Adult kidney cancer has no known cause and may be discovered incidentally through examinations for other conditions. It is often widespread when initially found. Recent scientific understanding points to a genetic cause, more so than other cancers.
Adult kidney cancer is detected in one of three ways: Patients have blood in the urine, with or without a mass and /or pain in their flank; an abnormality is seen on an abdominal CAT scan or renal ultrasound; or the patient has signs of metastases, and a search for a primary source leads to the diagnosis of renal cancer.
Childhood kidney cancer, know as Wilm's tumour, occurs primarily in children younger than seven. At least 30 percent of Wilm's tumour cases are caused by inherited factors.