Misdiagnosis of Multiple Bone Metastases Due to Increased FDG Uptake in Polyostotic Fibrous Dysplasia

Abstract

It is well know that FDG is taken up by different tumor and active inflammation. Focal uptake of FDG may cause false-positive results in certain benign conditions. Fibrous dysplasia is a benign disorder of unknown cause in which the normal bone structure is replaced by fibrous connective tissue. X-ray CT and bone scan with technetium-99m-phosphate complexes has been used as a tool for diagnosing fibrous dysplasia. There have been very few reports of this, even if sometimes fibrous dysplasia showed increased FDG activity, it would be difficult to use PET to evaluate the disease because fibrous dysplasia does not always have increased metabolic activity. We report a rare case with polyostotic fibrous dysplasia which was misdiagnosed as multiple bone metastases due to increased FDG uptake in multiple foci of the whole body bones.