Therapy-related acute myeloid leukemia with chromosomal abnormalities involving t(9;22)(q34;q11) and t(3;21)(q26;q22) during chemotherapy for follicular lymphoma

This report describes a case of a patient who developed therapy-related acute myeloid leukemia five years after initiating chemotherapy for follicular lymphoma. The patient had been treated with multiple chemotherapeutic regimens, including anthracycline and etoposide (VP-16), as well as with radiation therapy for refractory follicular lymphoma over the preceding five years. The patient subsequently developed myelodysplastic syndrome (MDS) with karyotypic abnormalities of monosomy 7 and del (20) (q11; q13.3) followed by acute myeloid leukemia (AML) with an additional balanced translocation of t(9;22)(q34;q11) and t(3;21)(q26;q22). Reverse transcriptionpolymerase chain reaction amplification of the patient’s RNA showed a fusion transcript of minor BCR-ABL but not EVI1-RUNX1 (AML1) genes. Imatinib therapy resulted in regression of AML, but the patient soon became refractory to chemotherapy and died. Therapy-related acute leukemia develops mostly as non-lymphoid leukemia with unbalanced aberrations of monosomy 7 and 5 or balanced aberrations involving 11q23 and 21q22, but Philadelphia chromosome is uncommon. In addition, simultaneous occurrence of both t(9;22)(q34;q11) and t(3;21)(q26;q22) balanced aberrations in t-MDS/t-AML is a very rare event. The balanced translocations detected in this case suggest another mechanism by which t-AML can develop after chemotherapy and radiation therapy for follicular lymphoma.