Key Points for This Section

Wilms tumor and other childhood kidney tumors are diseases in which malignant (cancer) cells form in the tissues of the kidney. Having certain genetic syndromes or birth defects can increase the risk of developing Wilms tumor. Having certain conditions may be associated with renal cell carcinoma. Possible signs of Wilms tumor and other childhood kidney tumors include a lump in the abdomen and blood in the urine. Tests that examine the kidney and the blood are used to detect (find) Wilms tumor and other childhood kidney tumors. Wilms tumor and other childhood kidney tumors are usually diagnosed and removed in surgery. Certain factors affect prognosis (chance of recovery) and treatment options.

Wilms tumor and other childhood kidney tumors are diseases in which malignant (cancer) cells form in the tissues of the kidney.

Wilms tumor

Wilms tumor and other kidney tumors are diseases in which malignant (cancer) cells are found in the kidney. In Wilms tumor, one or more tumors may be found in one or both kidneys. There are two kidneys, one on each side of the backbone, above the waist. Tiny tubules in the kidneys filter and clean the blood, taking out waste products and making urine. The urine passes from each kidney through a long tube called a ureter into the bladder. The bladder holds the urine until it is passed from the body.

Wilms tumor may spread to the lungs, liver, or nearby lymph nodes.

Diffuse hyperplastic perilobar nephroblastomatosis (DHPLN) is a condition in which abnormal tissue grows on the outer part of one or both kidneys. Children with DHPLN are at risk for developing a type of Wilms tumor that grows quickly. Frequent follow-up testing is important for at least 7 years after the child is diagnosed with DHPLN.

Other kidney tumors

Clear cell sarcoma of the kidney, rhabdoid tumor of the kidney, neuroepithelial tumor of the kidney, renal cell cancer (RCC), and mesoblastic nephroma are also childhood kidney tumors, but they are not related to Wilms tumor.

• Clear cell sarcoma of the kidney is a type of kidney tumor that may spread to the lung, bone, brain, and soft tissue.
• Rhabdoid tumor of the kidney is a type of cancer that occurs mostly in children under age 2. It grows and spreads quickly, often to the lungs and brain.
• Neuroepithelial tumors of the kidney are rare and usually occur in young adults. They grow and spread quickly.
• Renal cell carcinoma occurs rarely in children. The tumor can spread to the lungs, bones, liver, and lymph nodes.
• Mesoblastic nephroma is a tumor of the kidney that is usually diagnosed within the first 3 months of life. It may also be found during an ultrasound before birth. Mesoblastic nephroma occurs more often in males than females.

Having certain genetic syndromes or birth defects can increase the risk of developing Wilms tumor.

Anything that increases your risk of getting a disease is called a risk factor. Wilms tumor may be part of a genetic syndrome that affects growth or development. A genetic syndrome is a set of symptoms or conditions that occur together and is usually caused by abnormal genes. Certain birth defects can also increase a child's risk for developing Wilms tumor. The following genetic syndromes and birth defects have been linked to Wilms tumor:

• WAGR (Wilms tumor, aniridia, ambiguous genitalia, and mental retardation) syndrome.
• Beckwith-Wiedemann syndrome.
• Hemihypertrophy.
• Denys-Drash syndrome.
• Cryptorchidism.
• Hypospadias.

Children with these genetic syndromes and birth defects should be screened for Wilms tumor every three months until age 8. An ultrasound test may be used for screening.

Having certain conditions may be associated with renal cell carcinoma.

Renal cell carcinoma may be related to the following conditions:

• Von Hippel-Lindau disease (an inherited condition that causes abnormal growth of blood vessels).
• Tuberous sclerosis (an inherited disease marked by noncancerous fatty cysts in the kidney).
• Neuroblastoma and/ or sickle cell disease.

Possible signs of Wilms tumor and other childhood kidney tumors include a lump in the abdomen and blood in the urine.

These and other symptoms may be caused by kidney tumors. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur in the child:

• A lump, swelling, or pain in the abdomen.
• Blood in the urine.
• Fever for no known reason.

Tests that examine the kidney and the blood are used to detect (find) Wilms tumor and other childhood kidney tumors.

The following tests and procedures may be used:

• Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
• Complete blood count (CBC): A procedure in which a sample of blood is drawn and checked for the following:
  • The number of red blood cells, white blood cells, and platelets.
  • The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
  • The portion of the blood sample made up of red blood cells.
• Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it.
• Liver function test: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by the liver. A higher than normal amount of a substance can be a sign that the liver is not working as it should.
• Renal function test: A procedure in which blood or urine samples are checked to measure the amounts of certain substances released into the blood or urine by the kidneys. A higher or lower than normal amount of a substance can be a sign that the kidneys are not working as they should.
• Urinalysis: A test to check the color of urine and its contents, such as sugar, protein, blood, and bacteria.
• Ultrasound exam: A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. An ultrasound of the abdomen is done to diagnose a kidney tumor.
• CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
• Abdominal x-ray: An x-ray of the organs inside the abdomen. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
• Biopsy: The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer.

Wilms tumor and other childhood kidney tumors are usually diagnosed and removed in surgery.

Once a kidney tumor is found, surgery is done to find out whether or not the tumor is cancer. If the tumor is only in the kidney, the surgeon will remove the whole kidney (nephrectomy). If there are tumors in both kidneys or if the tumor has spread outside the kidney, a piece of the tumor will be removed. In any case, a sample of tissue from the tumor is sent to a pathologist, who looks at it under a microscope to check for signs of cancer.

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis (chance of recovery) and treatment options depend on the following:

• How different the tumor cells are from normal kidney cells.
• The stage of the cancer.
• The type and size of the tumor.
• The age of the child.
• Whether the tumor can be completely removed in surgery.
• Whether the cancer has just been diagnosed or has recurred (come back).
• Whether there are any abnormal chromosomes or genes.
• Whether the patient is treated by pediatric experts with experience in treating patients with Wilms tumor.

Glossary Terms

The area of the body that contains the pancreas, stomach, intestines, liver, gallbladder, and other organs.

An x-ray of the organs inside the abdomen. An x-ray is a type of radiation that can pass through the body and onto film, making pictures of areas inside the body. X-rays may be used to help diagnose disease.

Not normal. An abnormal lesion or growth may be cancerous, premalignant (likely to become cancer), or benign.

The bones, muscles, tendons, and other tissues that reach from the base of the skull to the tailbone. The backbone encloses the spinal cord and the fluid surrounding the spinal cord. Also called spine, spinal column, and vertebral column.

A large group of single-cell microorganisms. Some cause infections and disease in animals and humans. The singular of bacteria is bacterium.

A rare, overgrowth disorder in which babies are large at birth and may develop low blood sugar. Other common symptoms are a large tongue, large internal organs, and defects of the abdominal wall near the navel. Beckwith-Wiedemann syndrome increases the risk of developing certain cancers, especially Wilms tumor.

The removal of cells or tissues for examination by a pathologist. The pathologist may study the tissue under a microscope or perform other tests on the cells or tissue. There are many different types of biopsy procedures. The most common types include: (1) incisional biopsy, in which only a sample of tissue is removed; (2) excisional biopsy, in which an entire lump or suspicious area is removed; and (3) needle biopsy, in which a sample of tissue or fluid is removed with a needle. When a wide needle is used, the procedure is called a core biopsy. When a thin needle is used, the procedure is called a fine-needle aspiration biopsy.

The organ that stores urine.

A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.

A procedure in which a sample of blood is examined to measure the amounts of certain substances made in the body. An abnormal amount of a substance can be a sign of disease in the organ or tissue that produces it.

A tube through which the blood circulates in the body. Blood vessels include a network of arteries, arterioles, capillaries, venules, and veins.

A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

Part of a cell that contains genetic information. Except for sperm and eggs, all human cells contain 46 chromosomes.

A rare type of kidney cancer, in which the inside of the cells look clear when viewed under a microscope. Clear cell sarcoma can spread from the kidney to other organs, most commonly the bone, but also including the lungs, brain, and soft tissues of the body.

CBC. A test to check the number of red blood cells, white blood cells, and platelets in a sample of blood. Also called blood cell count and CBC.

A condition in which one or both testicles fail to move from the abdomen, where they develop before birth, into the scrotum. Cryptorchidism may increase the risk for development of testicular cancer. Also called undescended testicles.

Computed tomography scan. A series of detailed pictures of areas inside the body taken from different angles; the pictures are created by a computer linked to an x-ray machine. Also called computed tomography scan, computerized tomography, computerized axial tomography scan, and CAT scan.

A sac or capsule in the body. It may be filled with fluid or other material.

A rare disorder that causes kidney failure before age 3, abnormal development of the sexual organs, and, in most cases, Wilms tumor (a type of kidney cancer). Children with Denys-Drash syndrome are also at high risk of some other types of cancer. Also called DDS.

The process of identifying a disease, such as cancer, from its signs and symptoms.

Widely spread; not localized or confined.

An increase in body temperature above normal (98.6 degrees F), usually caused by disease.

Monitoring a person's health over time after treatment. This includes keeping track of the health of people who participate in a clinical study or clinical trial for a period of time, both during the study and after the study ends.

The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein.

Inherited; having to do with information that is passed from parents to offspring through genes in sperm and egg cells.

Refers to the genitalia (external and internal sex organs and glands).

The substance inside red blood cells that binds to oxygen in the lungs and carries it to the tissues.

An abnormal increase in the number of cells in an organ or tissue.

Transmitted through genes that have been passed from parents to their offspring (children).

Use of a syringe and needle to push fluids or drugs into the body; often called a "shot."

One of a pair of organs in the abdomen. Kidneys remove waste from the blood (as urine), produce erythropoietin (a substance that stimulates red blood cell production), and play a role in blood pressure regulation.

A large organ located in the upper abdomen. The liver cleanses the blood and aids in digestion by secreting bile.

A blood test to measure the blood levels of certain substances released by the liver. A high or low level of certain substances can be a sign of liver disease.

One of a pair of organs in the chest that supplies the body with oxygen, and removes carbon dioxide from the body.

A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called lymph gland.

Cancerous. Malignant tumors can invade and destroy nearby tissue and spread to other parts of the body.

Surgery to remove a kidney or part of a kidney. In a partial nephrectomy, part of one kidney or a tumor is removed, but not an entire kidney. In a simple nephrectomy, one kidney is removed. In a radical nephrectomy, an entire kidney, nearby adrenal gland and lymph nodes, and other surrounding tissue are removed. In a bilateral nephrectomy, both kidneys are removed.

Cancer that arises in immature nerve cells and affects mostly infants and children.

Having to do with tissue made up of sensory cells, such as tissue found in the ear, nose, and tongue.

A part of the body that performs a specific function. For example, the heart is an organ.

A doctor who identifies diseases by studying cells and tissues under a microscope.

Having to do with children.

An exam of the body to check for general signs of disease.

A type of blood cell that helps prevent bleeding by causing blood clots to form. Also called a thrombocyte.

The likely outcome or course of a disease; the chance of recovery or recurrence.

A molecule made up of amino acids that are needed for the body to function properly. Proteins are the basis of body structures such as skin and hair and of substances such as enzymes, cytokines, and antibodies.

To become well and healthy again.

To come back or to return.

RBC. A cell that carries oxygen to all parts of the body. Also called RBC and erythrocyte.

The most common type of kidney cancer. It begins in the lining of the renal tubules in the kidney. The renal tubules filter the blood and produce urine. Also called hypernephroma.

A test in which blood or urine samples are checked for the amounts of certain substances released by the kidneys. A higher- or lower-than-normal amount of a substance can be a sign that the kidneys are not working the way they should. Also called kidney function test.

A malignant tumor of either the central nervous system (CNS) or the kidney. Malignant rhabdoid tumors of the CNS often have an abnormality of chromosome 22. These tumors usually occur in children younger than 2 years.

Something that may increase the chance of developing a disease. Some examples of risk factors for cancer include age, a family history of certain cancers, use of tobacco products, certain eating habits, obesity, lack of exercise, exposure to radiation or other cancer-causing agents, and certain genetic changes.

Checking for disease when there are no symptoms. Since screening may find diseases at an early stage, there may be a better chance of curing the disease. Examples of cancer screening tests are the mammogram (breast), colonoscopy (colon), Pap smear (cervix), and PSA blood level and digital rectal exam (prostate). Screening can also include checking for a person’s risk of developing an inherited disease by doing a genetic test.

Refers to muscle, fat, fibrous tissue, blood vessels, or other supporting tissue of the body.

A computer picture of areas inside the body created by bouncing high-energy sound waves (ultrasound) off internal tissues or organs. Also called an ultrasonogram.

The extent of a cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer, and whether the cancer has spread from the original site to other parts of the body.

A doctor who removes or repairs a part of the body by operating on the patient.

A procedure to remove or repair a part of the body or to find out whether disease is present. An operation.

An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.

A set of symptoms or conditions that occur together and suggest the presence of a certain disease or an increased chance of developing the disease.

A group or layer of cells that work together to perform a specific function.

A genetic disorder in which benign (noncancerous) tumors form in the kidneys, brain, eyes, heart, lungs, and skin. This disease can cause seizures, mental disabilities, and different types of skin lesions.

An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancerous), or malignant (cancerous). Also called neoplasm.

A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echo patterns are shown on the screen of an ultrasound machine, forming a picture of body tissues called a sonogram. Also called ultrasonography.

The tube that carries urine from the kidney to the bladder.

A test that determines the content of the urine.

Fluid containing water and waste products. Urine is made by the kidneys, stored in the bladder, and leaves the body through the urethra.

A blood vessel that carries blood to the heart from tissues and organs in the body.

A rare inherited disorder in which blood vessels grow abnormally in the eyes, brain, spinal cord, adrenal glands, or other parts of the body. People with von Hippel-Lindau syndrome have a higher risk of developing some types of cancer. Also called VHL syndrome.

Refers to a blood cell that does not contain hemoglobin. White blood cells include lymphocytes, neutrophils, eosinophils, macrophages, and mast cells. These cells are made by bone marrow and help the body fight infections and other diseases. Also called WBC.

A disease in which malignant (cancer) cells are found in the kidney, and may spread to the lungs, liver, or nearby lymph nodes. Wilms tumor usually occurs in children younger than 5 years old.

A type of high-energy radiation. In low doses, x-rays are used to diagnose diseases by making pictures of the inside of the body. In high doses, x-rays are used to treat cancer.