ABSTRACT
Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic malignancy characterized by persistent monocytosis with overlapping features of both myeloproliferative neoplasm (MPN) and a myelodysplastic syndrome (MDS) [1–10]. Myelodysplastic component includes dysplasia, and myeloproliferative component includes leukocytosis and splenomegaly. Median age at diagnosis of CMML varies between 65 and 75 years and there is a 2:1 male predominance [11,12]. Some patients present with skin lesions due to leukemia cutis (see Chapter 44). Similar to blastic phase (crisis) of chronic myeloid leukemia (CML), some patients with CMML may directly present in the blastic phase (acute myeloid leukemia, AML). An algorithmic approach to monocytosis and CMML is presented in Figure 1.8 (Chapter 1).
