Lymphoblastic lymphoma.

Lymphoblastic lymphoma (LBL) is a neoplasm of immature B cells committed to the B-(B-LBL) or T-cell lineage (T-LBL) that accounts for approximately 2% of all lymphomas. Although histological features are usually sufficient to distinguish lymphoblastic from mature B- or T-cell neoplasms, of greater importance for diagnosis is the characterization of immunophenotype by flow cytometry. LBL occurs more commonly in children than in adults, mostly in males. A bone marrow involvement <25% (or 20% according to WHO) formally distinguishes LBL from ALL. The prognosis of LBL has dramatically improved with the use of intensive ALL-type chemotherapy regimens, which includes intensive intrathecal chemotherapy prophylaxis and consolidation with mediastinal irradiation. Patients with adverse prognostic features assessed by postinduction CT/positron emission tomography scans (PET) and minimal residual disease analysis (MRD) should be considered for high-dose chemotherapy and stem cell transplantation. Further therapeutic progresses are expected from the introduction of new drugs and targeting agents.