Pediatric Acute Lymphocytic Leukemia
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Introduction
ALL comprises perhaps 85% of childhood leukemias. It has a peak incidence of 1-5 years.
The Case of...
a simple case introducing clincial presentation and calling for a differential diagnosis to get students thinking.
Causes and Risk Factors
The causes of ALL are largely unknown.
Some possible risk factors include:
- ionizing radiation
- potentially response to viral infections
- EBV
- prior chemotherapy
- Down syndrome
- chromosome fragility syndromes
- inherited mutations: TEL-AML
Pathophysiology
Pre-B cell (common) ALL
- large cells
- pre-B cell phenotype
- Tdt positive
- CALLA (CD10) positive
- surface Ig negative/positive
- CD19/20 positive
T-cell ALL
- often mediastinal mass
- may have skin involvement
- often v high WCC (>100 x 109/L)
- CD2+, CD3+
- surface Ig -
Mature B-cell ALL
- lymphadenopathy common
- WCC often low
- CD19+
- surface IgG +
- "Burkitt's type" leukemia
- often presents as advanced B-cell lymphoma
Infant ALL
- poor prognosis
- commonly mixed lineage, or null
- come from high up in the progenitor chain
- characteristic genetic mutations:
- MLL gene rearrangement (t 4:11)
Signs and Symptoms
- history
- physical exam
History
- pallor and tiredness from anemia
- recurrent infections
- bruising and bleeding from thrombocytopenia
- constitutional symptoms: fever, night sweats, weight loss
- lymphadenopathy
- hepatosplenomegaly
- testicular enlargement
- headaches and cranial nerve palsies
- skin rashes
- occasional mediastinal masses
- bone pain and fractures
- gum hypertrophy
Physical Exam
Investigations
- lab investigations
- diagnostic imaging
Lab Investigations
CBC
- may be normal or mildly abnormal
- usually pancytopenia
- anemia with normal or increased MCV
- blasts in peripheral blood
- occasional hyperleukocytosis
bone marrow
- biopsy: histology and immunocytochemistry
- smear: morphology, flow cytometry, cytogenetics, molecular genetics
lumbar puncture
lymph node biopsy
mass biopsy
Diagnostic Imaging
Differential Diagnosis
Treatments
chemotherapy
- induction with multi-agents
- consolidation blocks
- intensification blocks
- maintenance
- 2 years in girls, 3 years in boys
craniospinal and testicular radiotherapy
intrathecal chemotherapy with methotrexate
stem cell transplants
supportive care:
- infection prophylaxis and treatment
- blood and platelet transfusions
- organ-specific support
- nutrition
- psychosocial care
Consequences and Course
It is now possible to stratify patients within at least four risk categories, and base treatment accordingly.
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Resources and References
Topic Development
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