Typical morphologic findings in PB and marrow of a CML patient prior to treatment and after 8 months on imatinib mesylate.
(A) The pretreatment PB smear shows leukocytosis with circulating granulocytic precursors and basophilia, typical of chronic-phase CML (WBC count, 38.7 × 109/L; platelet count, 207 × 109/L). (B) After 8 months of imatinib mesylate treatment, the PB shows adequate counts and normal morphology (WBC count, 3.5 × 109/L; platelet count, 148 × 109/L). (C) The pretreatment bone marrow aspirate is hypercellular, with marked myeloid hyperplasia and M/E ratio exceeding 10:1. (D) The bone marrow aspirate at 8 months is mildly hypocellular with an M/E ratio of 1:1 owing to decreased myeloid precursors and a relative increase in erythroid precursors. Histiocytes are mildly increased. (E,G) Pretreatment bone marrow biopsy with hypercellularity (more than 95%) and marked myeloid and megakaryocytic hyperplasia, typical of chronic phase CML. (F,H) At 8 months, the biopsy shows borderline hypocellularity (30% to 40%) with mildly decreased myeloid and relatively increased erythroid precursors. Panels A, B show original magnification × 600; panels C, D, × 400; panels E, F, × 200; panels G, H, × 600. Panels A-D are Wright-Giemsa–stained; panels E-H are hematoxylin and eosin–stained.
