Diagnostic Criteria

Childhood acute myeloid leukemia (AML) is diagnosed when the bone marrow has 20% or greater blasts or when a lower blast percentage is present but molecular evaluation reveals an AML-defining genetic abnormality.[1] For information about the defining abnormalities, see the World Health Organization (WHO) Classification System for Childhood AML section.

Leukemia is considered to be disseminated in the hematopoietic system at diagnosis, even in children with AML who present with isolated chloromas (also called granulocytic or myeloid sarcomas). These children invariably develop AML in months to years if they do not receive systemic chemotherapy. AML may invade nonhematopoietic (extramedullary) tissue such as meninges, brain parenchyma, testes or ovaries, or skin (leukemia cutis). Extramedullary leukemia is more common in infants than in older children with AML.[2] In one retrospective analysis, leukemia cutis did not have an adverse impact on outcomes of infants when they were treated with traditional chemotherapy.[3]