Introduction
Acute myeloid leukemia (AML) is a clinical and genetic heterogeneous
disease that accounts for 15–20% of all childhood
leukemias.1 Accurate diagnosis and treatment
strategies have resulted in tremendous improvements in the overall
survival (OS) rate of pediatric AML, which is now nearly
60%.2-5 Different subtypes of AML vary in clinical
presentation characteristics and therapeutic effects. AML and
hyperleukocytosis have been associated with an unfavorable
prognosis,6,7 which can lead to a higher probability
of early death due to complications
of
leukostasis, tumor lysis syndrome, and
disseminated
intravascular coagulation
(DIC)
.8
Hyperleukocytosis has no explicit diagnostic criteria so far, but
usually
refers to white blood cell
(WBC)
counts greater than 100×109/L in the peripheral blood
of patients with acute leukemia.9 However,
it
should be noted that WBC counts below this arbitrary threshold can also
cause
leukocytosis-related
complications. Hyperleukocytosis has been defined as more than
50×109/L in some studies in adults with
AML.10-12To
our knowledge, no study has reported the characteristics and prognosis
of
hyperleukocytosis
(described as
WBC
count ≥50×109/L) in pediatric AML patients. The
objective of our study was to contribute to recognizing this group of
pediatric AML. In this study, we analyzed the clinical characteristics
(sex, age, cytogenetics, molecular biology) and outcome in an unselected
cohort of de novo non-M3 AML pediatric patients.