This is a medical question of type : information 
 What is (are) AIDS-Related Lymphoma ? 
 Key Points
                    - AIDS-related lymphoma is a disease in which malignant (cancer) cells form in the lymph system of patients who have acquired immunodeficiency syndrome (AIDS).    - There are many different types of lymphoma.    - Signs of AIDS-related lymphoma include weight loss, fever, and night sweats.    - Tests that examine the lymph system and other parts of the body are used to help detect (find) and diagnose AIDS-related lymphoma.    - Certain factors affect prognosis (chance of recovery) and treatment options.
                
                
                    AIDS-related lymphoma is a disease in which malignant (cancer) cells form in the lymph system of patients who have acquired immunodeficiency syndrome (AIDS).
                    AIDS is caused by the human immunodeficiency virus (HIV), which attacks and weakens the body's immune system. The immune system is then unable to fight infection and disease. People with HIV disease have an increased risk of infection and lymphoma or other types of cancer. A person with HIV disease who develops certain types of infections or cancer is then diagnosed with AIDS. Sometimes, people are diagnosed with AIDS and AIDS-related lymphoma at the same time. For information about AIDS and its treatment, please see the AIDSinfo website.   AIDS-related lymphoma is a type of cancer that affects 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 brain, stomach, thyroid gland, and skin.   Sometimes AIDS-related lymphoma occurs outside the lymph nodes in the bone marrow, liver, meninges (thin membranes that cover the brain) and gastrointestinal tract. Less often, it may occur in the anus, heart, bile duct, gingiva, and muscles.
                
                
                    There are many different types of lymphoma.
                    Lymphomas are divided into two general types:         -  Hodgkin lymphoma.    -  Non-Hodgkin lymphoma.        Both Hodgkin lymphoma and non-Hodgkin lymphoma may occur in patients with AIDS, but non-Hodgkin lymphoma is more common. When a person with AIDS has non-Hodgkin lymphoma, it is called AIDS-related lymphoma. When AIDS-related lymphoma occurs in the central nervous system (CNS), it is called AIDS-related primary CNS lymphoma.   Non-Hodgkin lymphomas are grouped by the way their cells look under a microscope. They may be indolent (slow-growing) or aggressive (fast-growing). AIDS-related lymphomas are aggressive. There are two main types of AIDS-related non-Hodgkin lymphoma:         -  Diffuse large B-cell lymphoma (including B-cell immunoblastic lymphoma).    -  Burkitt or Burkitt-like lymphoma.        For more information about lymphoma or AIDS-related cancers, see the following PDQ summaries:         -  Adult Non-Hodgkin Lymphoma Treatment     -  Childhood Non-Hodgkin Lymphoma Treatment     -  Primary CNS Lymphoma Treatment     -  Kaposi Sarcoma Treatment