Acute Myocardial Infarction during Induction Chemotherapy for Acute MLL t(4;11) Leukemia with Lineage Switch and Extreme Leukocytosis.

INTRODUCTION: In patients with acute leukemias hemorrhage is the most frequent problem. Vein thrombotic events may appear rarely but arterial thromboses are exceptionally rare. We present a patient with acute leukemia and bilateral deep leg vein thrombosis who developed an acute myocardial infarction (AMI) during induction chemotherapy. The etiology and treatment of AMI in patients with acute leukemia, which is a rare occurrence, is discussed.

CASE OUTLINE: In April of 2012 a 37-year-old male presented with bilateral deep leg vein thrombosis and malaise. Laboratory data were as follows: Hb 118 g/L, WBC 354 x 10(9)/L (with 91% blasts in differential leukocyte count), platelets 60x109/L. Bone marrow aspirate and immunophenotype revealed the presence of acute lymphoblastic leukemia. Cytogenetic analysis was as follows: 46,XY,t(4;11)(q21:q23) [2]/62-82,XYt(4;11)[18]. Molecular analysis showed MLL-AF4 rearrangement. The patient was on low molecular weight heparin and combined chemotherapy according to protocol HyperCVAD. On day 10 after chemotherapy he got chest pain. Three days later AMI was diagnosed (creatine kinase 66 U/L, CK-MB 13U/L, troponin 1.19 µg/L). Electrocardiogram showed the ST elevation in leads D1, D2, aVL, V5 and V6 and "micro q" in D1. On echocardiography, hypokinesia of the left ventricle and ejection fraction of 39% was found. After recovering from AMI and restoring left ventricle ejection fraction to 59%, second course of HyperCVAD was given. The control bone marrow aspirate showed 88% of blasts but with monoblastic appearance. Flow cytometry confirmed a lineage switch from lymphoblasts to monoblasts. In further course of the disease he was treated with a variety of chemotherapeutic combinations without achieving remission. Eventually, palliative chemotherapy was administered to reduce the bulk of blasts. He died five months after the initial diagnosis.

CONCLUSION: AMI in young adults with acute leukemia is a very rare complication which may occur in patients with very high white blood cell count in addition with presence of a CD56 adhesion molecule and other concomitant thrombophilic factors. The treatment of AMI in patients with acute leukemias should include antiplatelet and anticoagulant therapy, even with more aggressive methods depending on patient's age and clinical risk assessment.