Objective FTo investigate the clinical characteristics of atypical chronic myeloid leukemia (aCML) and characterize the aCML.

Methods FFrom 2003 to 2007, the consecutive samples of 54 MDS/MPD patients in Sino-US Shanghai Leukemia Cooperative Group were collected by prospective methods and diagnosed with WHO classification. We identified 9 aCML cases and analyzed the clinical and laboratory data of these cases.

Results FThe median age of 9 cases was 66 years old(range 38~78y). The ratio of male and female is 1:1.25. Median hemoglobin concentration was 76.5g/L(range 43.3~116), median white blood cell count 27.5×109/L(range 7.55 ~317.2), median neutrophil percentage 66.4%(range 43.3~83.5), median basophil percentage 2.86%(range 0.24~5.79), median monocyte percentage 7.59%(range 0.92~16.3), median platelet 77.6×109/L(range 20.7 ~504)and median marrow blast percentage 2.5 %(range 0.5~6). Abnormal karyotype occurred in 20% of all patients. Median survival was 11.5 months(2.5 `44months).

Conclusions FaCML occurs rarely and is associated with a poor prognosis. The major distinguishing features of aCML are Ph(−)or BCR/ABL(−)and severe dysgranulopoiesis. In addition, hepatosplenomegaly and leukocytosis are less prominent in aCML than chronic myeloid leukemia(CML) and chronic myelomonocytic leukemia (CMML). Anemia is much severe than CML and CMML.

Disclosures: No relevant conflicts of interest to declare.

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