The inv(7)(p15q34) chromosomal abnormality which juxtaposes part of the HOXA gene cluster on 7p15 to the TCRβ locus on 7q34, has been described in a subset of cases of T-cell lymphoblastic leukemia, but its presence in cases of B-cell lymphoblastic leukemia is virtually unknown. Herewith, we report a case of a B-cell lymphoblastic leukemia with inv(7)(p15q34). The patient received standard induction chemotherapy, which failed to produce remission. After treatment with blinatumomab, a bispecific T-cell engager, the follow-up bone marrow biopsy showed no evidence of persistent/ relapsed B-cell lymphoblastic leukemia. The unique cytogenetics of this case may have contributed to its resistance of standard induction chemotherapy.