A neoplasm of immature malignant lymphocytes (lymphoblasts) committed to the B-cell or T-cell lineage. Neoplasms involving the bone marrow and the peripheral blood are called precursor lymphoblastic leukemias or acute lymphoblastic leukemias. Neoplasms involving primarily lymph nodes or extranodal sites are called lymphoblastic lymphomas. -- 2003. The disease is MONDO_0003538 (precursor lymphoblastic lymphoma/leukemia). Also known as: precursor lymphoblastic leukemia/lymphoma, precursor lymphoid neoplasm.