A patient with hyperparathyroidism secondary to chronic renal failure
had multiple bony lesions with increased activity on both immediate st
atic as well as delayed scintiphotos. One lesion in the distal femur w
as also exceptionally hot on the flow phase. Plain radiographs demonst
rated lytic lesions with sclerotic margins and a narrow zone of transi
tion. Open biopsy revealed histology consistent with brown tumor (oste
oclastoma).