This is a medical question of type : information 
 What is (are) Wilms Tumor and Other Childhood Kidney Tumors ? 
 Key Points
                    - Childhood kidney tumors are diseases in which malignant (cancer) cells form in the tissues of the kidney.    - There are many types of childhood kidney tumors.         - Wilms Tumor     - Renal Cell Cancer (RCC)     - Rhabdoid Tumor of the Kidney     - Clear Cell Sarcoma of the Kidney     - Congenital Mesoblastic Nephroma     - Ewing Sarcoma of the Kidney     - Primary Renal Myoepithelial Carcinoma     - Cystic Partially Differentiated Nephroblastoma      - Multilocular Cystic Nephroma      - Primary Renal Synovial Sarcoma     - Anaplastic Sarcoma of the Kidney         - Nephroblastomatosis is not cancer but may become Wilms tumor.    - Having certain genetic syndromes or other conditions can increase the risk of Wilms tumor.    - Tests are used to screen for Wilms tumor.    - Having certain conditions may increase the risk of renal cell cancer.    - Treatment for Wilms tumor and other childhood kidney tumors may include genetic counseling.    - 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) and diagnose Wilms tumor and other childhood kidney tumors.    - Certain factors affect prognosis (chance of recovery) and treatment options.
                
                
                    Childhood kidney tumors are diseases in which malignant (cancer) cells form in the tissues of the kidney.
                    There are two kidneys, one on each side of the backbone, above the waist. Tiny tubules in the kidneys filter and clean the blood. They take out waste products and make urine. The urine passes from each kidney through a long tube called a ureter into the bladder. The bladder holds the urine until it passes through the urethra and leaves the body.
                
                
                    There are many types of childhood kidney tumors.
                    Wilms Tumor    In Wilms tumor, one or more tumors may be found in one or both kidneys. Wilms tumor may spread to the lungs, liver, bone, brain, or nearby lymph nodes. In children and adolescents younger than 15 years old, most kidney cancers are Wilms tumors.        Renal Cell Cancer (RCC)     Renal cell cancer is rare in children and adolescents younger than 15 years old. It is much more common in adolescents between 15 and 19 years old. Children and adolescents are more likely to be diagnosed with a large renal cell tumor or cancer that has spread. Renal cell cancers may spread to the lungs, liver, or lymph nodes. Renal cell cancer may also be called renal cell carcinoma.       Rhabdoid Tumor of the Kidney     Rhabdoid tumor of the kidney is a type of kidney cancer that occurs mostly in infants and young children. It is often advanced at the time of diagnosis. Rhabdoid tumor of the kidney grows and spreads quickly, often to the lungs or brain.    Children with a certain change in the SMARCB1 gene are checked regularly to see if a rhabdoid tumor has formed in the kidney or has spread to the brain:            - Children younger than one year old have an ultrasound of the abdomen every two to three months and an ultrasound of the head every month.     - Children one to four years old have an ultrasound of the abdomen and an MRI of the brain and spine every three months.              Clear Cell Sarcoma of the Kidney     Clear cell sarcoma of the kidney is a type of kidney tumor that may spread to the lung, bone, brain, or soft tissue. When it recurs (comes back) after treatment, it often recurs in the brain or lung.       Congenital Mesoblastic Nephroma     Congenital mesoblastic nephroma is a tumor of the kidney that is often diagnosed during the first year of life. It can usually be cured.        Ewing Sarcoma of the Kidney     Ewing sarcoma (previously called neuroepithelial tumor) of the kidney is rare and usually occurs in young adults. These tumors grow and spread to other parts of the body quickly.       Primary Renal Myoepithelial Carcinoma     Primary renal myoepithelial carcinoma is a rare type of cancer that usually affects soft tissues, but sometimes forms in the internal organs (such as the kidney). This type of cancer grows and spreads quickly.       Cystic Partially Differentiated Nephroblastoma      Cystic partially differentiated nephroblastoma is a very rare type of Wilms tumor made up of cysts.       Multilocular Cystic Nephroma     Multilocular cystic nephromas are benign tumors made up of cysts and are most common in infants, young children, and adult women. These tumors can occur in one or both kidneys.     Children with this type of tumor also may have pleuropulmonary blastoma, so imaging tests that check the lungs for cysts or solid tumors are done. Since multilocular cystic nephroma may be an inherited condition, genetic counseling and genetic testing may be considered. See the PDQ summary about Unusual Cancers of Childhood Treatment for more information about pleuropulmonary blastoma.       Primary Renal Synovial Sarcoma     Primary renal synovial sarcoma is a cyst-like tumor of the kidney and is most common in young adults. These tumors grow and spread quickly.       Anaplastic Sarcoma of the Kidney      Anaplastic sarcoma of the kidney is a rare tumor that is most common in children or adolescents younger than 15 years of age. Anaplastic sarcoma of the kidney often spreads to the lungs, liver, or bones. Imaging tests that check the lungs for cysts or solid tumors may be done. Since anaplastic sarcoma may be an inherited condition, genetic counseling and genetic testing may be considered.
                
                
                    Nephroblastomatosis is not cancer but may become Wilms tumor.
                    Sometimes, after the kidneys form in the fetus, abnormal groups of kidney cells remain in one or both kidneys. In nephroblastomatosis (diffuse hyperplastic perilobar nephroblastomatosis), these abnormal groups of cells may grow in many places inside the kidney or make a thick layer around the kidney. When these groups of abnormal cells are found in a kidney after it was removed for Wilms tumor, the child has an increased risk of Wilms tumor in the other kidney. Frequent follow-up testing is important at least every 3 months, for at least 7 years after the child is treated.
                
                
                    Treatment for Wilms tumor and other childhood kidney tumors may include genetic counseling.
                    Genetic counseling (a discussion with a trained professional about genetic diseases and whether genetic testing is needed) may be needed if the child has one of the following syndromes or conditions:          - A genetic syndrome or condition that increases the risk of Wilms tumor.    - An inherited condition that increases the risk of renal cell cancer.    -  Rhabdoid tumor of the kidney.    - Multilocular cystic nephroma.