MLT GlobeHematology: WBC disorders & leukemias – page 8
145 Hematology MCQs on WBC disorders & leukemias with answers and explanations.
Under the WHO 5th edition, AML with erythroid differentiation (pure erythroid leukemia) requires erythroid precursors of at least 80% of marrow cells with pronormoblasts of at least:
The WHO 5th edition defines this entity by ≥80% erythroid precursors with ≥30% pronormoblasts; it is strongly linked to biallelic TP53 changes. Myeloblast percentage is not used in this definition.
A newborn with Down syndrome has circulating blasts that disappear without treatment within 3 months. Which gene is typically mutated in these blasts?
Transient abnormal myelopoiesis in Down syndrome is caused by GATA1 mutations in megakaryoblasts and usually resolves spontaneously, though some infants later develop myeloid leukemia.
Under the WHO 5th edition, a patient with MDS-type dysplasia and 12% marrow blasts is best classified as:
MDS-IB2 has 10–19% marrow blasts (or 5–19% in blood, or Auer rods); MDS-IB1 has 5–9% marrow or 2–4% blood blasts. AML usually needs ≥20% blasts unless a defining genetic change is present.
A healthy 75-year-old has normal blood counts, but sequencing finds a DNMT3A mutation at 8% variant allele frequency. This is best called:
CHIP is a somatic myeloid driver mutation (VAF ≥2%) without cytopenia or a diagnosed hematologic neoplasm. MDS requires cytopenia and morphologic dysplasia or defining genetics.
An elderly man has skin nodules and pancytopenia. Blasts are CD4+, CD56+, CD123 bright, TCL1+ and negative for MPO and CD3. The diagnosis is:
Co-expression of CD4, CD56, bright CD123 and TCL1 without lineage markers is typical of BPDCN, which often starts in the skin. Monocytic AML expresses CD14/CD64 and lysozyme.