What is a brown tumor?
A brown tumor is one manifestation of hyperparathyroidism which occurs as a result of excess osteoclastic activity and represents localized accumulation of fibrous tissue and giant cells. Hemosiderin deposition gives the characteristic brown hue to this lesion on gross pathology. It should be noted that this is not a neoplastic lesion. On radiography, one or more lytic foci are seen in the bones.