Abstract
There are many reports on the effective diagnosis of acute leukemia by MRI. Acute leukemia patients with the symptom of bone pain or joint pain frequently show abnormal MRI findings in the bone or bone marrow. Here, we report the case of a 7-year-old girl who presented to our hospital with leg pain and was diagnosed with precursor B-cell acute lymphoblastic leukemia (ALL). An abnormal MRI finding suggested leukemic infiltration in the left femur. Following induction therapy, complete bone marrow remission was confirmed and the MRI finding improved to some extent. After further therapy, MRI revealed a new abnormal finding in the femur bone marrow. Suspecting a relapse, we performed FDG-PET/CT, which revealed a normal finding. Because there were no relapse symptoms except for the MRI finding including the negative result of FDG-PET/CT, we assumed that this finding was bone marrow reconversion. The abnormal MRI finding improved gradually as therapy proceeded to completion. Sequential observation is important for distinguishing it from leukemia relapse, and an abnormal MRI finding in the bone marrow does not always indicate a relapse.
