title: Cytopenia, dysplasia, and monocytosis: a precursor to chronic myelomonocytic leukemia or a distinct subgroup? Case reports and review of literature.
abstract: Chronic myelomonocytic leukemia (CMML) consists of disorders with overlapping dysplastic and proliferative features. The diagnosis of CMML requires absolute monocytosis (> 1000/μL) in addition to other criteria outlined by the World Health Organization (WHO) classification.(1) Monocytosis not reaching 1000/μL has been observed in myelodysplastic syndrome (MDS) and presents a diagnostic challenge in classification especially if increases in leukocyte count occurring during disease shifts the monocyte count into the absolute range. We discuss the laboratory and clinical features of 3 patients with myelodysplasia and associated monocytosis. Absolute neutropenia was the dominant feature at presentation, with mild anemia, thrombocytopenia, monocytosis (as a percentage), multilineage dysplasia, and increased myeloblasts, consistent with a diagnosis of refractory anemia with excess blasts (RAEB). Absolute monocytosis fulfilling the diagnostic criteria for CMML developed over 6-8 months, prompting a change in diagnosis. Two of 3 patients had normal cytogenetic examinations. JAK2 V617F mutation was detected after transformation to CMML in 1 of them; in the other, a novel translocation t(5;12)(p13;q24) was observed at the time of progression to acute leukemia. The use of different diagnostic terminologies--MDS, dysplasia with reactive monocytosis, myeloproliferative, and myeloproliferative/myelodysplastic syndromes by different and even the same pathologists at different times created confusion among the clinicians and patients. The disease course in these 3 patients was characterized by better survival and prolonged time to progression to acute leukemia, than predicted based on the original diagnosis of RAEB, suggesting that MDS with monocytosis may represent a subgroup distinct from MDS or CMML.
authors.affiliation: Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA. zsingh@uams.edu
authors.forename: Zeba N
authors.initials: ZN
authors.lastname: Singh
authors.forename: Ginell R
authors.initials: GR
authors.lastname: Post
authors.forename: Elias
authors.initials: E
authors.lastname: Kiwan
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Maddox
mesh_terms: D000368:Aged; D002869:Chromosome Aberrations; D005260:Female; D006801:Humans; D007621:Karyotyping; D015477:Leukemia, Myelomonocytic, Chronic / Q000150:complications / Q000175:diagnosis* / Q000235:genetics / Q000401:mortality; D007964:Leukocytosis / Q000150:complications / Q000175:diagnosis* / Q000235:genetics; D008297:Male; D009154:Mutation / Q000235:genetics; D009190:Myelodysplastic Syndromes / Q000150:complications / Q000175:diagnosis* / Q000235:genetics; D010198:Pancytopenia / Q000150:complications / Q000175:diagnosis* / Q000235:genetics