Childhood pre-B cell acute lymphoblastic leukemia with translocation t(1;19)(q21.1;p13.3) and two additional chromosomal aberrations involving chromosomes 1, 6, and 13: a case report

BACKGROUND The translocation t(1;19)(q23;p13), which results in the TCF3-PBX1 chimeric gene, is one of the most frequent rearrangements observed in B cell acute lymphoblastic leukemia. It appears in both adult and pediatric patients with B cell acute lymphoblastic leukemia at an overall frequency of 3 to 5%. Most cases of pre-B cell acute lymphoblastic leukemia carrying the translocation t(1;19) have a typical immunophenotype with homogeneous expression of CD19, CD10, CD9, complete absence of CD34, and at least diminished CD20. Moreover, the translocation t(1;19) correlates with known clinical high risk factors, such as elevated white blood cell count, high serum lactate dehydrogenase levels, and central nervous system involvement; early reports indicated that patients with translocation t(1;19) had a poor outcome under standard treatment. CASE PRESENTATION We report the case of a 15-year-old Syrian boy with pre-B cell acute lymphoblastic leukemia with abnormal karyotype with a der(19)t(1;19)(q21.1;p13.3) and two yet unreported chromosomal aberrations: an interstitial deletion 6q12 to 6q26 and a der(13)t(1;13)(q21.1;p13). According to the literature, cases who are translocation t(1;19)-positive have a significantly higher incidence of central nervous system relapse than patients with acute lymphoblastic leukemia without the translocation. Of interest, central nervous system involvement was also seen in our patient. CONCLUSIONS To the best of our knowledge, this is the first case of childhood pre-B cell acute lymphoblastic leukemia with an unbalanced translocation t(1;19) with two additional chromosomal aberrations, del(6)(q12q26) and t(1;13)(q21.3;p13), which seem to be recurrent and could influence clinical outcome. Also the present case confirms the impact of the translocation t(1;19) on central nervous system relapse, which should be studied for underlying mechanisms in future.