ALL in children, AML in adults, CLL in the elderly, CML in middle age
Mnemonic
Two axes: acute or chronic, myeloid or lymphoid.
- ALL - children, the commonest childhood cancer. Peak at 2 to 5. Blasts, TdT positive. Good prognosis. Associated with Down syndrome
- AML - adults, median 65. Auer rods. Acute promyelocytic (M3) carries t(15;17) and causes DIC, and is treated with all-trans retinoic acid
- CLL - the elderly, often incidental lymphocytosis. Smear (smudge) cells. Can transform to high grade lymphoma (Richter’s)
- CML - middle age. Philadelphia chromosome t(9;22), BCR-ABL, treated with imatinib. Massive splenomegaly, and may transform to blast crisis
“ALL in children, AML in adults, CML in middle age, CLL in the old”, roughly in decades.
Acute means blasts and marrow failure, so it presents over weeks with anaemia, infection and bleeding; chronic means mature cells, so it presents insidiously or incidentally.
Expansion
| Leukaemia | Typical age | Hallmark |
|---|---|---|
| ALL (acute lymphoblastic) | Children, peak 2 to 5 | Commonest childhood cancer; TdT positive; good prognosis; CNS and testicular sanctuary sites |
| AML (acute myeloid) | Adults, median 65 | Auer rods; acute promyelocytic subtype with t(15;17) causes DIC and responds to all-trans retinoic acid |
| CML (chronic myeloid) | 40 to 60 | Philadelphia chromosome t(9;22), BCR-ABL; treated with imatinib; may transform to blast crisis |
| CLL (chronic lymphocytic) | Over 60 | Smudge cells; often incidental lymphocytosis; warm autoimmune haemolytic anaemia; Richter transformation to lymphoma |
Acute leukaemias present with marrow failure: anaemia, infection from neutropenia, and bleeding from thrombocytopenia, with blasts on the film. They progress over weeks.
Chronic leukaemias progress over years and are often found incidentally on a blood count.
Auer rods in AML are needle-shaped azurophilic granules; their presence in acute promyelocytic leukaemia is associated with disseminated intravascular coagulation, which is a haematological emergency.
Imatinib in CML is the landmark example of targeted therapy, transforming a fatal disease into a chronic one by inhibiting the BCR-ABL tyrosine kinase.