Pb1836 burkitt leukemia/lymphoma in children: cytogenetic characteristics and outcome

Background: Burkitt Leukemia/Lymphoma (BL/L) is a rare, highly aggressive hematological malignancy. Although children diagnosed with advanced stage disease have a poorer prognosis, current therapeutic protocols achieve an overall survival rate in children of up to 90%. Cytogenetically, BL/L is characterized by the translocations t(8;14) and the variant t(8;22) and t(2;8) which juxtapose immunoglobulin sequences with the c-MYC oncogene, leading to its constitutional expression which is crucial for the BL/L pathogenesis. Aims: The aim of our study is: a) to present the clinical characteristics, the immunophenotype and the chromosomal abnormalities of BL/L patients, b) to estimate the therapeutic efficacy of the current treatment protocols. Methods: Four children, diagnosed with BL/L and treated in our center in the last decade are included in this study. Five colour FACS immunophenotype and cytogenetics were applied at diagnosis. All children were treated according to the FAB/LMB96 protocol for BL/L. All remain in follow-up. Results: The age of diagnosis ranged from 4 to 14 years (mean: 8.5yrs). The male to female ratio was 4/0, and confirmed the male preponderance that is described in the literature.The most common clinical manifestations were prolonged mild fever, fatigue and lack of appetite. One child presented with lower limb myalgia, caused by an abdominal paravertebral lymphoid mass. WBC count ranged from 6.000 to 12.000/ml for all children except one case where excessive leukocytosis, with WBC count over 85.000/ml, was observed. Lactate dehydrogenase (LDH) ranged from 3.031 to 7.075U/L (mean:5.000). All 4 patients's blasts shared the same immunophenotypic features, ie: CD45+++CD19+CD10+CD20+skappa+. Cytogenetic evaluation revealed aneuploidy in two patients, including one case with monosomy 4 and one case with heavy hyperploidy (78,XY). Immunoglobulin-MYC translocation was found in all patients, including 3 cases with the t(8;14) translocation and one case with the t(8;22) variant. In the case with the heavy hyperploidy, a double t(8;14) was observed. All patients were treated according to the FAB/LMB96 protocol, and achieved complete first remission. All remain in first complete remission, with a mean follow-up time of 4.4 years, without late effects Summary/Conclusion: Immunophenotypic features were typical for the diagnosis and did not show any variations related to cytogenetics. Cytogenetic abnormalities such as monosomy 4, heavy hyperploidy (78,XY) or a double t(8;14) that were observed in our cases had no negative impact on the outcome. Despite the small number of patients, our findings appear promising and confirm the favorable prognosis of children with BL/L. Our results confirm that FAB/LMB96 is an effective protocol for the treatment of childhood BL/L.