Acute myeloid leukemia with new complex t(8;21;22) induced hemophagocytic lymphohistiocytosis: A case report

The balanced translocation t(8;21;22)(q22;q22;q11.2) is not reported previously, although t(8;21)(q22;q22) is seen in approximately 7% of adults and most frequent abnormality in children with newly diagnosed acute myeloid leukemia (AML). AML-associated hemophagocytic lymphohistiocytosis (HLH) is a rare event, reported only of limited numbers. The present study reports a very rare case of t(8;21;22)(q22;q22;q11.2) with AML, not reported previously, and developed HLH at the same time.

A 15-year-old girl presented with a history of bleeding gums and high fever, leukocytosis, anemia, and thrombocytopenia. While waiting the result of bone marrow aspirate, the HLH-associated examinations were abnormal. Bone marrow aspirate showed a hypercellular marrow with 1% myeloblasts. The cytogenetic and molecular studies revealed the presence of abnormal karyotype-46, XX, t(8;21;22)(q22;q22;q11.2) and RUNX1-RUNX1T1 fusion gene. Genetic detections of HLH showed heterozygous genetic variants in lysosomal trafficking regulator (LYST). Hence, she was diagnosed with AML with t(8;21;22)(q22;q22;q11.2) and HLH.

All HLH clinical symptoms disappeared after the 4 weeks treatment of HLH. Then the patient received standard AML induction chemotherapy and the leukemia relapsed after 2 cycles of high-dosed consolidation therapy. Eventually, the patient received emergent paternal haploidentical hematopoietic stem cell transplantation based on the complex variant translocation, leukemia replased state and HLH with compound heterozygotes mutation, and achieved sustained remission with RUNX1-RUNX1T1 negative for more than 1 year.

Patients with some specific recurrent cytogenetic abnormalities should be diagnosed with AML regardless of the blast count, for example t(8;21). We should improve the understanding of complex variant translocations. HLH-related genetic mutations were not only found in primary HLH, but also in second HLH.