Blast crises CML are characterized by:

Ans. b (Blast cells in blood >/= 20%). (Ref. Harrison, 17th, Chapter 104; 18th/Chapter 109. ; Robbins, Pathology, 7th, 314, 697)CML# Disease acceleration is defined by:- Development of increasing degrees of anemia unaccounted for by bleeding or therapy;- Cytogenetic clonal evolution; or- Blood or marrow blasts between 10 and 20%,- Blood or marrow basophils 20%, or- Platelet count <100,000/L.# Blast crisis is defined as:- Acute leukemia, with blood or marrow blasts 20%.- Hyposegmented neutrophils may appear (Pelger-Huet anomaly).# Very low leukocyte alkaline phosphatase i.e. LAP score is feature of CML (vs. leukemoid reaction).# Imatinib is DOC for CML.Blast cells can be classified as myeloid, lymphoid, erythroid, or undifferentiated, based on morphologic, cytochemical, and immunologic features. Occurrence of de novo blast crisis or following imatinib is rare.