ider(9)(q10)t(9;22)(q34;q11) is a recurrent chromosomal abnormality in acute lymphoblastic leukemia and lymphatic blastic phase of chronic myelogenous leukemia

A case of adult B lymphoblastic leukemia with ider(9)(q10)t(9;22)(q34;q11.2) and der(19)t(1;19)(q23;p13.3)

In B lymphoblastic leukemia/lymphoma (B-ALL/LBL), t(9;22)(q34;q11.2) and t(1;19)(q23;p13.3) are recurrent cytogenetic abnormalities. The concurrent occurrence of both abnormalities is very rare, and only 3 cases have been previously reported. Here, we report a case of adult B-ALL with ider(9)(q10)t(9;22)(q34;q11.2) and der(19)t(1;19)(q23;p13.3). A literature review revealed that ider(9) (q10)t(9;22) is a rare variant of t(9;22) with a deletion of the short arm of chromosome 9. Fifteen cases of ider(9)(q10)t(9;22) have been reported. This abnormality is specific to precursor B-lymphoid neoplasms, such as B-ALL or B-lymphoid blast phase of CML, and is associated with disease progression or short survival. The cytogenetic abnormality t(1;19) is also specific to B-ALL. In most instances of t(1;19), TCF3 is fused to PBX1; however, a few cases have identical translocations but no TCF3-PBX1 fusion, as was observed in our patient. We describe the first case of ider(9)(q10)t(9;22) in combination with TCF3-PBX1 negative t(1;19). The patient underwent imatinib therapy in addition to intensive chemotherapy, but failed to achieve remission.

[A Case of Acute Lymphoblastic Leukemia with ider(9)(q10)t(9;22)(q34;q11.2).]

ider(9)(q10)t(9;22)(q34;q11.2) is an isochromosome for the long arm of a derivative chromosome 9 generated by a t(9;22), resulting from the deletion of the short arm of chromosome 9. It is known to be rarely observed in acute lymphoblastic leukemia (ALL) or lymphoblastic crisis transformed from chronic myelogenous leukemia. We herein describe a 26-year-old female patient with precursor B-cell ALL, cytogenetically characterized by ider(9)(q10)t(9;22). Fluorescence in situ hybridization analysis showed two ABL-BCR fusion signals on the derivative chromosome 9 and one BCR-ABL fusion signal on the derivative chromosome 22. Although a t(9;22) and a deletion of the short arm of chromosome 9 are known to be associated with a poor prognostic factor in acute lymphoblastic leukemia, a larger study is needed to determine the prognosis of ider(9)(q10)t(9;22) cases.