This is a medical question of type : information 
 What is (are) Childhood Hodgkin Lymphoma ? 
 Key Points
                    - Childhood Hodgkin lymphoma is a disease in which malignant (cancer) cells form in the lymph system.    - There are two types of childhood Hodgkin lymphoma.     - Epstein-Barr virus infection increases the risk of childhood Hodgkin lymphoma.    - Signs of childhood Hodgkin lymphoma include swollen lymph nodes, fever, night sweats, and weight loss.    - Tests that examine the lymph system are used to detect (find) and diagnose childhood Hodgkin lymphoma.    - Certain factors affect prognosis (chance of recovery) and treatment options.
                
                
                    Childhood Hodgkin lymphoma is a disease in which malignant (cancer) cells form in the lymph system.
                    Childhood Hodgkin lymphoma is a type of cancer that develops in the lymph system, which is part of the body's immune system. The immune system protects the body from foreign substances, infection, and diseases. The lymph system is made up of the following:         -  Lymph: Colorless, watery fluid that carries white blood cells called lymphocytes through the lymph system. Lymphocytes protect the body against infections and the growth of tumors.    -  Lymph vessels: A network of thin tubes that collect lymph from different parts of the body and return it to the bloodstream.     -  Lymph nodes: Small, bean-shaped structures that filter lymph and store white blood cells that help fight infection and disease. Lymph nodes are located along the network of lymph vessels found throughout the body. Clusters of lymph nodes are found in the neck, underarm, abdomen, pelvis, and groin.    -  Spleen: An organ that makes lymphocytes, filters the blood, stores blood cells, and destroys old blood cells. The spleen is on the left side of the abdomen near the stomach.    -  Thymus: An organ in which lymphocytes grow and multiply. The thymus is in the chest behind the breastbone.    -  Tonsils: Two small masses of lymph tissue at the back of the throat. The tonsils make lymphocytes.    -  Bone marrow: The soft, spongy tissue in the center of large bones. Bone marrow makes white blood cells, red blood cells, and platelets.         Lymph tissue is also found in other parts of the body such as the stomach, thyroid gland, brain, and skin.   There are two general types of lymphoma: Hodgkin lymphoma and non-Hodgkin lymphoma. (See the PDQ summary on Childhood Non-Hodgkin Lymphoma Treatment for more information.)     Hodgkin lymphoma often occurs in adolescents 15 to 19 years of age. The treatment for children and adolescents is different than treatment for adults. (See the PDQ summary on Adult Hodgkin Lymphoma Treatment for more information.)
                
                
                    There are two types of childhood Hodgkin lymphoma.
                    The two types of childhood Hodgkin lymphoma are:         -  Classical Hodgkin lymphoma.    -  Nodular lymphocyte-predominant Hodgkin lymphoma.        Classical Hodgkin lymphoma is divided into four subtypes, based on how the cancer cells look under a microscope:         - Lymphocyte-rich classical Hodgkin lymphoma.     - Nodular sclerosis Hodgkin lymphoma.     - Mixed cellularity Hodgkin lymphoma.     - Lymphocyte-depleted Hodgkin lymphoma.