Representative peripheral blood and BM smears from patients with CMML. (A) Peripheral blood smear showing monocytosis with morphologically normal monocytes. May-Grünwald-Giemsa (MGG) staining; magnification, ×400. (B) Peripheral blood smear showing monocytes with nuclear and cytoplasmic abnormalities. MGG staining; magnification, ×1250. (C) BM smear showing high cellularity and hyperplasia of the granulocytic series with < 10% blasts (CMML-1). Erythroid cells are morphologically normal. MGG staining; magnification, ×1000. (D) BM smear from a patient with CMML-2 showing hyperplasia of monocytes and their precursors. The sum of blasts plus the promonocytes is 18%. MGG staining; magnification, ×1000.