2.1Incidence

•Seventy-five percent of children with leukemia have acute lymphoblastic leukemia (ALL)

•Thirty-eight out of 1 million children are newly diagnosed with ALL annually

•Male to female ratio is 1:1.2

•Peak incidence, 2–5 years of age

•Incidence in white children is twice as high as in nonwhite children

2.2Clinical Manifestation

2.2.1General Aspects

•The history and symptoms reflect the degree of bone marrow infiltration by leukemic cells and the extramedullary involvement of the disease

•The duration of symptoms may be days to several weeks, occasionally several months

•Sometimes diagnosis in an asymptomatic child results from an incidental finding in a blood cell count

•Often low-grade fever, signs of infection, fatigue, bleeding (i.e., epistaxis, petechiae), pallor

Summary of characteristics and symptoms of 724 children with ALL (CCSG)