MRI and 18F-FDG-PET/CT in a rare case of early (precursor) B-lymphoblastic leukaemia with bone involvement as initial manifestation.

A 4-year old girl presenting gait difficulty was referred for spine X-ray and Magnetic Resonance Imaging (MRI). MRI showed several diffuse hypointense signals in sacral and lumbar vertebrae. In order to exclude a possible lymphoproliferative disease a 18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) was requested. The PET/CT scan confirmed the MRI findings and demonstrated additional findings in the sternum. Therefore, a bone marrow biopsy was performed and a diagnosis of acute lymphoblastic leukaemia - early B type was made.