Childhood Leukemias - book cover

Diagnosis and Classification

Reprinted from Childhood Leukemias with permission from Cambridge University Press; edited by St. Jude pediatric oncologist, Ching-Hon Pui, MD.

Precise diagnosis and classification are essential to successful treatment and biologic study of the childhood leukemias.  In broadest terms, the leukemias are classified as acute versus chronic and as lymphoid versus myeloid.  The vast majority of childhood leukemia cases are acute, unlike those in adults. The most common subtype, acute lymphoblastic (lymphocytic or lymphoid) leukemia (ALL) accounts for 75% to 80% of all childhood cases, with acute myeloid (myelocytic, myelogenous or nonlymphoblastic) leukemia (AML) comprising approximately 20% and chronic myeloid leukemia (CML) approximately 2%.

Careful examination of bone marrow is essential to establishing the diagnosis of leukemia because as many as 20% of patients with acute leukemia lack circulating blast cells at diagnosis, and the morphology of leukemic cells in peripheral blood may differ from that in marrow.

Since the late nineteenth century, the first step in classifying acute leukemia has been to distinguish ALL from AML... For therapeutic purposes, it is important to distinguish ALL with myeloid-associated antigen expression (My+ ALL) from AML with lymphoid-associated antigen expression (Ly+ AML), using lineage-specific markers to define the primary lineage.  Treatment of individual cases should be based on the primary disease process (i.e., ALL vs. AML).


Childhood Leukemias is available in the libraries of most medical schools and from major book sellers.

Ching-Hon Pui, M.D.
St. Jude Children's Research Hospital
Publisher: Cambridge University Press
ISBN: 0521581761