The bone marrow image was left shifted and the myelogram showed a large number of basophils with 5% primitive cells. Basophilic mesophilic and late granulocytes are also increased, with left shifted nuclei and coarse basophilic granules in the cytoplasm. Then, why does the patient appear to have a left shift in the bone marrow image phenomenon? Here is a brief introduction: the left shift of the bone marrow image is a manifestation of basophilic granulocytic leukemia, some patients with acute granulocytic leukemia and monocytic leukemia have t(6;9)(p23;q34) abnormality, basophils increase in the bone marrow, but not in the peripheral blood, while patients with CML have t(9;22)(q34;q11) abnormality, and both diseases have chromosome 9 (q34) abnormality, and both have basophilic granulocytes, and both have basophilic granules. Abnormalities and both have basophilia, suggesting that the chromosome 9 breakpoint gene may influence basophil production.Peterson et al. performed an ultrastructural analysis of leukemic primitive cells from 455 cases of patients with acute leukemia, and found that acute basophilic leukemia was present in 8 cases, accounting for less than 2% of acute leukemias. However, Quattrin statistics showed that of the 2,152 cases of hematologic malignancies admitted to the Naples Hospital in Italy from 1959 to 1973, this disease accounted for 4.5% of acute leukemias. The disease is characterized by the presence of immature basophils (more than 1/3 of the total number of leukocytes) in the blood, which persist throughout the course of the disease.