Definition of Lymphoma, lymphoblastic Lymphoma, lymphoblastic: A rapidly moving, aggressive form of lymphoma that is most often seen in children or young adults. Since it is a tumor consisting of early lymphocyte precursors (lymphoblasts) it is believed to represent the same disease entity as acute lymphoblastic leukemia (ALL). The World Health Organization (WHO) classification has unified lymphoblastic lymphoma and lymphoblastic leukemia into one entity known as precursor B- or T-cell lymphoblastic leukemia/lymphoma. Treatment may include chemotherapy, radiation, surgery, medications, and bone marrow transplant. Last Editorial Review: 7/1/2016 Back to MedTerms online medical dictionary A-Z List Need help identifying pills and medications?