A Case of Acute Lymphocytic Leukaemia with t(3;13) and Central Nervous System Leukemia after Allogenic Cord Blood Transplantation

Background: Acute lymphoblastic leukemia (ALL) is a neoplastic cancer characterized by clonal expansion of leukemic cells in lymph organs and bone marrow. Lots of kinds of different chromosomal translocation can be found in those leukemic cells. However, the role of the abnormal chromosomals and genes in leukemogenesis is not yet fully understood. Identifying new chromosomal translocation can facilitate a better understanding of pathogenesis of this disease.

Case presentation: We report a rare case of acute lymphocytic leukaemia with t(3;13)(q29,q21). The patient was diagnosed pre-B-ALL with no abnormal chromosomal or gene fusion and achieved complete remission (CR) after induction chemotherapy. Ten months later, she relapsed in the consolidation with cytogenetics test showing 46,XX,t(3;13)(q29,q21). Given no CR after 2 chemotherapy regimens, she received salvage cord blood transplantation. Regular intrathecal methotrexate was applied to prevent central nervous system leukemia. Good graft-versus-leukemia (GVL) effect was induced by daily injection of low dose of IL-2 two months post transplantation. Minimal residual disease (MRD) negativity was maintained until central nervous system leukemia was found 8 months after transplantation. A whole exome sequencing was performed. Nine driver mutation genes and seven tumor genes were found.

Conclusions: We highly suspect that the relapse in central nervous system after transplantation is associated with the rare chromosomal translocation.