Multifocal metachronous giant cell tumor in a 15-year-old boy.

We report a case of multifocal metachronous giant cell tumor (GCT) that involved the fibula, tibia, and sacrum of a 15-year-old boy. Multifocal GCT of bone presenting in children is an exceedingly rare phenomenon; however, there is evidence that multifocal GCT presents, on average, at a younger age than solitary GCT. Pediatric radiologists should be aware of this when encountering a single lesion with characteristic radiographic features of GCT and when encountering multiple lytic skeletal lesions.