Burkitt Lymphoma is the fastest-growing type of B-cell non-Hodgkin lymphoma. It causes the cells in the lymphatic system to abnormally grow, eventually causing tumors. The lymphatic system is part of the immune system and includes the lymph nodes, spleen, thymus, bone marrow and lymphocytes, a specific type of white blood cell. Tumors are often found in the abdomen, live, spleen, jaw and other organs.