Mast cell leukemia (MCL) is a rare and aggressive hematologic malignancy with an extremely poor prognosis, for which no standard treatment regimen has been established. We herein reported the clinical data of a 67-year-old female MCL patient whose initial symptom was fatigue. Diagnosis of the aleukemic MCL subtype (KIT D816V-negative) was confirmed through multi-site bone marrow biopsies combined with morphological, immunophenotypic, immunohistochemical, and molecular biological analyses. Following two cycles of chemotherapy with azacitidine combined with imatinib, the patient achieved morphological complete remission in the bone marrow. However, the patient ultimately died due to cerebral hemorrhage secondary to bone marrow suppression. This case demonstrated that the combined regimen of azacitidine and imatinib has a good therapeutic effect on non-D816V mutant MCL, and is worthy of further clinical investigation.