Acute Myelogenous Leukemia (AML)

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

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