The role of peripheral blood, bone marrow aspirate and especially bone marrow trephine biopsy in distinguishing atypical chronic myeloid leukemia from chronic granulocytic leukemia and chronic myelomonocytic leukemia

Objectives: To better realize the features of peripheral blood (PB), bone marrow (BM) aspirate and especially BM trephine biopsy in atypical chronic myeloid leukemia (aCML). Methods: We studied PB, BM smears in 35 cases of aCML and compared with 84 cases of chronic granulocytic leukemia chronic phase (CGL-CP), 39 cases of chronic myelomonocytic leukemia (CMML). In addition, we evaluated characteristics of BM trephine biopsies in 21 cases of aCML and compared with 68 cases of CGL-CP, 20 cases of CMML. Results: All aCML patients presented with leukocytosis (median WBC 17.3 x 10<SU9</SU/L), 48% had moderate anemia, and 85% had thrombocytopenia. Values of monocytes, eosinophils, basophils, percentage of immature granulocytes and monocytes (0.63 +/- 0.41 x 10<SU9</SU/L, 0.18 +/- 0.16 x 10<SU9</SU/L, 0.09 +/- 0.08 x 10<SU9</SU/L, 6.27 +/- 3.09%, and 2.46 +/- 1.75%, respectively) were useful in distinguishing aCML from CGL-CP and CMML groups. The BM smears showed that striking dysgranulopoieis (100%), dyserythropoiesis (48.6%), percentage of blasts, nucleated erythrocytes, monocytes, eosinophils, and basophils (2.45 +/- 2.06%, 7.76 +/- 2.89%, 1.30 +/- 1.21%, 1.47 +/- 1.60%, and 1.15 +/- 1.08%, respectively) were all important parameters for a diagnosis of aCML. On BM trephine sections, aCML was characterized as hypercellularity, a moderate degree of reticulin fibrosis (71.4%), lymphocytopenia (76.2%), plasmacytopenia (90.5%), abnormal localization of immature precursors (28.5%), and absence of eosinophilia, basophilia, monocytosis. Furthermore, BM imprints, immunohistochemical, and cytochemical staining findings provided important morphological reference to BM trephine sections and made the identification of nucleated cells more convenient. Conclusions: Besides the findings observed in PB and BM aspirate, features of BM trephine biopsy (including BM trephine section, BM imprint, immunohistochemical, and cytochemical staining) can also aid in the diagnosis of aCML.