Kidney Tumors

Kidney tumors, also called renal tumors, are growths in the kidneys that can be benign or cancerous.

The kidneys are two bean-shaped organs about the size of a fist in the abdomen. They remove waste and extra water from the blood and help keep chemicals such as sodium, potassium and calcium balanced in the body. Kidneys also make hormones that help control blood pressure and stimulate bone marrow to make red blood cells.

Benign kidney tumors are slow-growing, noncancerous, and do not spread to surrounding tissues. Some benign kidney tumors include:

• Renal adema
• Renal oncoctoma
• Angiomyolipoma
• Fibroma
• Lipoma

A cancerous (malignant) kidney tumor can grow unchecked, invade healthy tissue and spread to other parts of the body. If it goes untreated, it can interfere with other organs and become life-threatening. Some cancerous kidney tumors include:

• Renal cell cancer
• Transitional cell cancer
• Wilms’ tumor

Many kidney tumors are found by chance and have no symptoms. When symptoms do occur, they may include:

• Blood in urine
• Pain or lump in lower back
• Feeling very tired
• Loss of appetite
• Unexpected weight loss
• Fever that isn’t caused caused by an infection that does not go away
• Anemia (low red blood cell count)

Doctors do not know what causes kidney tumors, but there are certain risk factors that increase the chance of malignant tumors. These risks include the following:

• Obesity
• Poor diet
• Family history of high blood pressure
• Kidney dialysis
• Heredity
• Smoking
• Drinking a lot of alcohol