 |  | Rudolph's Pediatrics Section 24. Neoplastic Disorders > Part 2. Hematologic Malignancies > Chapter 449. Acute Lymphoblastic LeukemiaAcute Lymphoblastic Leukemia: IntroductionJames B. Nachman | |
Topics Discussed: acute lymphocytic leukemia; b-cell development; leukemia; leukemia, b-cell, acute; leukemia, lymphocytic, acute, childhood; leukemia, t-cell; medical oncology; t-cell development.
Sections: References.
Excerpt:"Acute lymphoblastic leukemia (ALL)
is the most common childhood malignancy, accounting for almost 25% of
cancer diagnoses seen in children younger than age 15 years. Patients with
more than 25% lymphoid blasts in the bone marrow are considered
to have leukemia regardless of the presence of extramedullary disease. Patients
who have an extramedullary lymphoid mass and 5% to 25% lymphoid
blasts in the marrow are considered to have lymphoblastic lymphoma
with marrow involvement. There are approximately 2400 new cases
of ALL diagnosed in children and adolescents less than 20 years
of age each year in the United States.1The peak
incidence of ALL is in the 2- to 6-year-old age group. The incidence
of ALL appears to be highest in Hispanic children and lowest in
African American children.2In the developmental pathway of lymphocytes (see Fig.
449-1), maturation to the mature B-cell and T-cell state occurs
without the necessity of antigenic stimulation—so-called
antigen independent differentiation. When a B or T cell combines
with its specific antigen, proliferation
and differentiation occur, resulting in long-lived memory cells
for antigen recognition and plasma cells which secrete antibody
or T cells with various effector functions, such as cytotoxicity,
B-cell help, cytokine secretion, and so on. In B-lineage acute lymphoblastic
leukemia (ALL), approximately 98% of patients show a B-precursor
immunophenotype. The rare patient with mature B-cell leukemia has
a..."
The content above is only an
excerpt. For full access, log into an existing user account below, purchase an annual subscription, or
purchase a short-term subscription to the complete website.
offers pediatrics students,
educators, and practioners access to leading McGraw-Hill texts, interactive imaging
content, exclusive multimedia, and flexible curricular tools.
Timed access to all of AccessPediatrics
24 hours for $29.95
48 hours for $49.95
Or