Brown Tumor is seen in:

Brown tumor is usually seen in excess osteoclastic activities, such as hyperparathyroidism. It is a repairative process rather than neoplastic. In hyperparathyroidism there is excess parathyroid hormone (PTH) secreted, which leads to excess calcium resorption from the bones leading to "ostitis fibrosa cystica". Ref: Harrison's Principles of Internal Medicine, 17th Edition, Page 1765; Robbins Pathologic Basis of Disease, 8th Edition, Pages 1218, 1128.