Snapshot A 60-year-old man presents with fever, long-standing fatigue, and shortness of breath on exertion. He also complains of easy bruising and occasional bleeding from his gums. On physical exam, he has cervical lymphadenopathy and marked hepatosplenomegaly. Peripheral blood smear shows large blasts. Introduction Acute leukemia with pancytopenia Epidemiology median onset 65 years of age Subtypes M3 aka acute promyelocytic leukemia (APML) t(15;17) disruption of retinoic acid receptor (RAR) required for myeloblast maturation associated with DIC presence of Auer rods peroxidase positive eosinophilic cytoplasmic inclusions acute megakaryoblastic leukemia associated with Down syndrome < 5 years of age (recall leukemia in Down syndrome occurring in > 5 years of age = ALL) acute monocytic leukemia infiltration of gums Risk factors alkylating chemotherapy radiation myeloproliferative disorders Down syndrome Presentation Symptoms of pancytopenia (high WBC count but WBCs are dysfunctional) fatigue dyspnea infection due to dysfunctional blasts bleeding Physical exam lymphadenopathy fever hepatosplenomegaly Evaluation Peripheral blood smear > 20% blasts in blood smear Most accurate test = flow cytometry Bone marrow biopsy with cytogenetics myeloblasts with Auer rods in APL myeloperoxidase (MPO) positive CBC anemia thrombocytopenia ↓ mature WBCs Differential Diagnosis ALL Myelodysplastic syndrome CML blast crisis Leukemoid reaction Treatment Initial treatment with chemotherapy to induce remission cytarabine Bone marrow transplant after remission especially for cytogenetics revealing high chance of relapse All-trans-retinoic acid (ATRA) to those with M3 (APL) Prognosis, Prevention, and Complications Prognosis prognostic indicator is cytogenetics 90% complete response rate from initial chemotherapy in those with good cytogenetics relapse rate > 50% with median survival 3-12 months Complications febrile neutropenia DIC gout tumor lysis syndrome