Philadelphia Chromosome-positive Acute Lymphoblastic Leukemia Incidentally Detected by Fluorodeoxyglucose-positron Emission Tomography/Computed Tomography at a Health Checkup

We herein report a case of Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-ALL) that was incidentally detected by fluorodeoxyglucose-positron emission tomography ((18)F-FDG PET)/computed tomography (CT) at a health checkup. At that time, the findings of a physical examination and blood tests were all normal, except for the diffuse bone marrow uptake (maximum standardized uptake value: 6.3). One month later, when the blood counts remained in the normal ranges, a bone marrow examination confirmed the diagnosis of Ph-ALL. Although a diffuse bone marrow uptake of (18)F-FDG is observed in some benign conditions, physicians should also consider the possibility of hematological malignancies, including acute leukemia, even when that is the only abnormal finding.