Leukemia, Acute Lymphoblastic (ALL) in Adults

Leukemia, Acute Lymphoblastic (ALL) in Adults is a topic covered in the 5-Minute Clinical Consult.

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Basics

Description

  • Acute lymphoblastic leukemia (ALL) in adults is the result of a clonal proliferation, survival, and impaired differentiation of immature lymphocytes. The World Health Organization (WHO) defines ALL as the presence of ≥25% lymphoblasts in the bone marrow (1), whereas the National Comprehensive Cancer Network (NCCN) uses a ≥20% as cutoff (2).
  • ALL and lymphoblastic lymphoma (LBL) can arise from the same precursor cell line, and therefore can be considered diseases along the same spectrum:
    • LBL presents as a mass, possibly, but not limited to, the mediastinum, with <25% blasts in the bone marrow.
    • ALL may present with a mass lesion but contains ≥25% bone marrow involvement.
  • Any organ can be affected.

Pregnancy Considerations
Many chemotherapy (CTX) drugs are teratogenic.

Pediatric Considerations
ALL is the most common malignancy in children—it accounts for 30% of all pediatric malignancies and 80% of pediatric leukemias (see “Acute Lymphoblastic Leukemia, Pediatric”).

Geriatric Considerations
Patients >60 years with ALL have a 42% mortality during induction CTX. The cause of death is usually CTX-related complications or relapse. Survival is often reduced due to poor tolerance of CTX, thus leading to dose reductions and ineffective medication delivery.

Epidemiology

  • Incidence of ALL is 1.7/100,000 per year.
  • Higher incidence in males, whites, those with history of radiation, CTX, or certain genetic disorders
  • Bimodal distribution: early peak at 4 to 5 years of age, second peak at ~50 years
  • 80% of cases occur in children, 20% in adults.

Etiology and Pathophysiology

Unknown in most patients

Genetics
  • Higher rates in monozygotic and dizygotic twins
  • Increased risk of ALL with diseases related to chromosomal instability: Bloom syndrome, Fanconi anemia, ataxia-telangiectasia, neurofibromatosis
  • Increased risk with inherited chromosomal abnormalities: Down syndrome, Klinefelter syndrome, etc.
  • See “Follow-Up Tests & Special Considerations.”

Risk Factors

  • Age >70 years, radiation exposure, and infection with HIV are risk factors for developing ALL.
  • Human T-cell lymphotropic virus type 1 is associated with adult T-cell ALL.
  • Epstein-Barr virus is associated with mature B-cell ALL.

-- To view the remaining sections of this topic, please or --

Basics

Description

  • Acute lymphoblastic leukemia (ALL) in adults is the result of a clonal proliferation, survival, and impaired differentiation of immature lymphocytes. The World Health Organization (WHO) defines ALL as the presence of ≥25% lymphoblasts in the bone marrow (1), whereas the National Comprehensive Cancer Network (NCCN) uses a ≥20% as cutoff (2).
  • ALL and lymphoblastic lymphoma (LBL) can arise from the same precursor cell line, and therefore can be considered diseases along the same spectrum:
    • LBL presents as a mass, possibly, but not limited to, the mediastinum, with <25% blasts in the bone marrow.
    • ALL may present with a mass lesion but contains ≥25% bone marrow involvement.
  • Any organ can be affected.

Pregnancy Considerations
Many chemotherapy (CTX) drugs are teratogenic.

Pediatric Considerations
ALL is the most common malignancy in children—it accounts for 30% of all pediatric malignancies and 80% of pediatric leukemias (see “Acute Lymphoblastic Leukemia, Pediatric”).

Geriatric Considerations
Patients >60 years with ALL have a 42% mortality during induction CTX. The cause of death is usually CTX-related complications or relapse. Survival is often reduced due to poor tolerance of CTX, thus leading to dose reductions and ineffective medication delivery.

Epidemiology

  • Incidence of ALL is 1.7/100,000 per year.
  • Higher incidence in males, whites, those with history of radiation, CTX, or certain genetic disorders
  • Bimodal distribution: early peak at 4 to 5 years of age, second peak at ~50 years
  • 80% of cases occur in children, 20% in adults.

Etiology and Pathophysiology

Unknown in most patients

Genetics
  • Higher rates in monozygotic and dizygotic twins
  • Increased risk of ALL with diseases related to chromosomal instability: Bloom syndrome, Fanconi anemia, ataxia-telangiectasia, neurofibromatosis
  • Increased risk with inherited chromosomal abnormalities: Down syndrome, Klinefelter syndrome, etc.
  • See “Follow-Up Tests & Special Considerations.”

Risk Factors

  • Age >70 years, radiation exposure, and infection with HIV are risk factors for developing ALL.
  • Human T-cell lymphotropic virus type 1 is associated with adult T-cell ALL.
  • Epstein-Barr virus is associated with mature B-cell ALL.

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