Abstract: Objective:To explore the clinical characteristics, the diagnostic framework, and the treatment methods of B cell lymphoblastic lymphoma (B-LBL), and to clarify the progress of diagnosis and treatment of B-LBL to improve the clinician's understanding of the disease and provide the guidance for prognostic evaluation and therapeutic options. Methods: The clinical data including symptoms, physical signs, ancillary testings,diagnosis, treatment and disease prognosis of a child suffered from B-LBL were retrospectively analyzed; in the meantime, the relative literatures were reviewed. Results: The patient was definitly diagnosed as B-LBL according to the clinical characteristics and received combination therapy with vincristine, daunorubicin, L-asparaginase, and prednisone as the first course, along with the intrathecal injection of methotrexate and dexamethasone to prevent central nervous system leukemia (CNS-L). The patient achieved complete remission (CR) 25 d after the first circle chemotherapy but was diagnosed as degree 4 myelosuppression. Therefore, the second cycle combination therapy was adjusted with cyclophosphamide, cytarabine and 6-MP, and the intrathecal injection to prevent CNS concomitantly. Degree Ⅳ myelosuppression appeared repeatedly after 2 cycles and the combination chemotherapy was reajdusted. So mercaptopurine and high dose of methotrexate were given as the 4th cycle,and CNS was prevented continously. The patient kept CR until the second cycle finished but get recurrence after the third chemotherapy(prolymphocytes 10%). Then remission and recurrence were found in the disease counrse during which mary chemotherapy methods were attempted until the patient got stable CR after treatment for 31 months. Then the patient was treated with oral mercaptopurine (50 g·d^-1) and methotrexate (25 mg per week) and kept disease-free survival for more than 3 years. Conclusion: B-LBL is a rapidly developed disease with the bone marrow involvement occurring in the short term and easy to relapse during treatment. However, it is extremely easy to transform to recurrent and refractory B-LBL after the first remission. It is of great importance to estimate the risk stratification and to evaluate the prognosis of LBL patients in order to treat as soon as possible for the improvement of one's life quality and the prolongation of survival.

Key words: refractory lymphoma, prognostic evaluation, lymphoblastic lymphoma, BFM-90 protocal