Acute leukemias vs Chronic leukemias
How to tell Acute leukemias and Chronic leukemias apart when a board question makes them look alike.
Acute equals blasts and rapid marrow failure; chronic equals mature clonal cells with CLL smudge cells or CML BCR-ABL myeloid expansion.
Side by side
ALL and AML present with rapid marrow failure from blasts; ALL is lymphoblast disease, while AML is myeloblast disease often with Auer rods and myeloperoxidase positivity.
CLL and CML are mature-cell clonal leukemias; CLL has mature fragile lymphocytes and smudge cells, while CML has BCR-ABL with granulocytic expansion and low LAP; both can transform but often present indolently.
Acute leukemias arise from immature precursor expansion that rapidly suppresses normal hematopoiesis.
Chronic leukemias involve more mature clonal cells, either mature B cells in CLL or myeloid lineage proliferation from BCR-ABL signaling in CML.
Blasts, cytopenias, high marrow blast burden, TdT in ALL, and Auer rods or MPO positivity in AML support acute leukemia.
Smudge cells support CLL; Philadelphia chromosome/BCR-ABL, basophilia, and low leukocyte alkaline phosphatase support CML.
The trap
A high white count is nonspecific; maturity, lineage markers, and signature smear/genetic clues decide the leukemia.
Watch it explained
The repair move
For any leukemia, ask acute versus chronic first, then lymphoid versus myeloid: (1) peripheral or marrow blasts above 20 percent equals acute leukemia (TdT-positive and CD10-positive lymphoblasts in ALL; Auer rods, MPO-positive cells, t(15;17) ATRA-responsive acute promyelocytic leukemia in AML); (2) mature clonal cells equal chronic leukemia (smudge cells with mature CD5-positive and CD20-positive B cells equals CLL, often elderly and asymptomatic; Philadelphia chromosome / BCR-ABL fusion plus basophilia plus low leukocyte alkaline phosphatase equals CML, treat with tyrosine kinase inhibitor like imatinib, dasatinib, or nilotinib); (3) age tilts add probability (ALL in children, AML in middle-aged adults, CLL in elderly Western patients, CML in middle-aged adults). The cure rate for ALL in children is high; APL has the best AML prognosis with ATRA-based therapy.
Try a free question
CoreA child has fever, bruising, bone pain, anemia, thrombocytopenia, and lymphoblasts that are TdT positive. Which diagnosis is most likely?
Show answer and explanation
Answer: A. ALL. A child with marrow failure and TdT-positive lymphoblasts most likely has ALL.
Why the other choices are tempting
- B. AML is myeloblast disease and often has Auer rods or MPO positivity.
- C. CLL is a mature B-cell leukemia of older adults.
- D. CML is BCR-ABL myeloid proliferation with granulocytes and basophils.
- E. Leukemoid reaction is reactive neutrophilia without blasts or clonal markers.
Flashcards
Tap a card to flip it.
What feature makes leukemia acute?
A high burden of immature blasts with rapid marrow failure makes leukemia acute.
What clue points to AML?
Myeloblasts with Auer rods or myeloperoxidase positivity point to AML.
Quick answers
What is the fastest way to tell Acute leukemias from Chronic leukemias?
Acute equals blasts and rapid marrow failure; chronic equals mature clonal cells with CLL smudge cells or CML BCR-ABL myeloid expansion.
What is the key clue for Acute leukemias?
ALL and AML present with rapid marrow failure from blasts; ALL is lymphoblast disease, while AML is myeloblast disease often with Auer rods and myeloperoxidase positivity.
What is the key clue for Chronic leukemias?
CLL and CML are mature-cell clonal leukemias; CLL has mature fragile lymphocytes and smudge cells, while CML has BCR-ABL with granulocytic expansion and low LAP; both can transform but often present indolently.
What is the common trap with Acute leukemias vs Chronic leukemias?
A high white count is nonspecific; maturity, lineage markers, and signature smear/genetic clues decide the leukemia.