Abstract
The patient was a male in his 60s. He was diagnosed as having acute myeloid leukemia (AML) on the basis of the finding of pancytopenia and blasts in the peripheral blood and 27.4% blasts in the bone marrow. However, because of left pneumonia and abnormally high CRP levels, chemotherapy was postponed to prioritize the treatment of pneumonia. About one month later, the pneumonia improved and the patient showed recovery of hematopoiesis of leukocytes and platelets. Moreover, another bone marrow biopsy revealed a marked decrease in the proportion of blasts to 2.4%. This phenomenon is called spontaneous remission of leukemia, and various causes such as infection, blood transfusions, and drugs have been speculated, but the detailed mechanism is unclear. In addition, this phenomenon is often transient and the disease type may change at the time of relapse; therefore, continued and detailed observation is necessary. Furthermore, when AML is associated with severe infection, the blast percentage may be lower than the baseline blast percentage, so caution is required at the time of diagnosis.
