B-lineage lymphoblastic lymphoma is a clinicopathologic entity distinct from other histologically similar aggressive lymphomas with blastic morphology

BACKGROUND. The authors present clinical, histopathologic, and immunophenot ypic data regarding B-lineage lymphoblastic lymphoma (B-LBL), a rare entity that has not been extensively studied. To emphasize some of its unique cli nical characteristics, the authors compare B-LBL with a group of histologic ally similar, very aggressive lymphomas, T-lineage lymphoblastic lymphoma ( T-LBL) and the blastoid variant of mantle cell lymphoma (BVMCL); all were e valuated concurrently. METHODS. Clinical data were obtained on 29 patients with very aggressive ly mphomas (12 B-LBLs, 10 T-LBLs, and 7 BVMCLs) from whom paraffin-embedded ma terial was available. The diagnoses were confirmed on review of the hematox ylin and eosin-stained slides and the immunophenotype data. RESULTS, The mean age of patients with B-LBL was 39 years. Patients present ed with both lymph node and extranodal disease, although involvement of the mediastinum and bone marrow was infrequent. Four were Stage I, 3 were Stag e II, 2 were Stage III, and 3 were Stage IV. B-LBL patients were treated pr imarily with cyclophosphamide, hydroxydaunomycin, vincristine, and predniso ne (CHOP), and one patient underwent allogeneic bone marrow transplantation . The mean follow-up time was 30 months. Seven of 11 had no evidence of dis ease at 48 months, whereas 4 patients were dead of disease at 5.6 months. T he overall median survival was 24 months. The clinical characteristics of B -LBL patients differed significantly from those of T-LBL patients; there wa s more frequent bone marrow and mediastinal involvement in T-LBL cases (P = 0.03 and 0.04, respectively). T-LBL patients were also less likely to achi eve a complete remission than B-LBL patients (P = 0.02). The mean age of BV MCL patients significantly exceeded that of B-LBL patients (P = 0.03). CONCLUSIONS, The authors believe that the distinction of B-LBL from its his tologic mimics, T-LBL and BVMCL, has important clinical implications. Patie nts with B-LBL present differently from those with the other very aggressiv e lymphomas studied, and they achieve complete remissions more often than T -LBL patients. Cancer 1999;85:2648-54. (C) 1999 American Cancer Society.