Acute Lymphoblastic Leukemia
•
Causes a wide spectrum of syndromes
– From involvement of bone marrow and peripheral
blood(leukemias) to those that cause masses
(lymphomas) in lymphoid organs.
•
Arise from the HSC, the common lymphoid
progenitor cell OR differentiated progenitors of
the T or B cell lineage
– T cell malignancies more aggressive, often involve
extranodal/extramedullary sites like skin, CNS,
mediastinum
– Neoplastic B cells secrete monoclonal proteins( IgM, IgG,
IgA) inappropriately causing increased viscosity of blood,
impairing blood flow
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Hematologic disorders characterized by malignant neoplastic
proliferation and accumulation of immature and dysfunctional
hematopoietic cells in the bone marrow.
Abnormality is an acquired genetic mutation within a
lymphoid precursor cell that gives rise to a clone of malignant
lymphocytes
These “cells” proliferate in an unregulated manner and do not
develop into mature cells
Additionally, they have an enhanced ability to self-renew and
have a resistance to cell death.
•
Seen in young children
– Peak incidence between 2-5 years old
• Onset symptoms can be insidious or abrupt
– Prognosis with treatment good, if no treatment
received, survival very short
•
Another peak seen in 60’s
– Onset symptoms rapid, fatigue, infections, bruising
– Prognosis not good
•
Symptoms are related to the replacement of
normal marrow elements with leukemic
lymphoblasts
– Anemia, thrombocytopenia, neutropenia
– Fever, weight loss, pallor, fatigue
– Petechiae and eechymoses present in half of the
patients
– Bone pain due to expansion of bm with leukemic
cells
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WBC variable from 0.1->50 x 109/L
◦ Usually around 10-12 x 109/L
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Neutropenia
Lymphoblasts
Normocytic, normochromic anemia
Thrombocytopenia (48-52 x 109/L)
Peripheral Blood
Bone marrow
Homogeneity of morphology of
lymphoblasts
Peripheral blood
Bone Marrow
Heterogeneous morphology of
lymphoblasts
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Age
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Blood
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Morphology
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Cytochemistry
◦ AML - mainly in adults
◦ ALL - common in children
◦ AML - anemia, neutropenia, thrombocytopenia, myeloblasts and
promyelocytes
◦ ALL - anemia, neutropenia, thrombocytopenia, lymphoblasts and
prolymphocytes
◦ AML - blasts are medium to large with more cytoplasm which may contain
granules, Auer rods, fine nuclear chromatin, distinct nucleoli
◦ ALL - blasts are small to medium with scarce cytoplasm, no granules, fine
nuclear chromatin and indistinct nucleoli
◦ AML - positive peroxidase and Sudan black B, negative TdT
◦ ALL - negative peroxidase and Sudan black B, positive TdT
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Two subgroups
◦ B-cell neoplasms
 Precursor B cell
 Mature B cell neoplasms
◦ T-cell neoplasms
 Precursor T cell
 Mature T cell neoplasms
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Three phases:
◦ Induction Therapy: eradicate blast population
◦ CNS prophylactic phase: Irradiation
◦ Cytoreductive or Maintenance chemotherapy
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McKenzie, Shirlyn B., and J. Lynne. Williams.
"Chapter 25." Introduction. Clinical
Laboratory Hematology. Boston: Pearson,
2010. Print.