Brown tumors are seen in:
Brown tumors are highly vascular lytic lesions of the skeleton seen in both primary and secondary hyperparathyroidism. They result from the accumulation of abundant fibrovascular tissue and osteoclast like giant cells. Ref: Robbin's Basic Pathology, 7th Edition, Pages 1186, 1286; Ohopaedic Pathology By Vincent J. Vigorita, Bernard Ghelman, Douglas Mintz, 2007, Page 187.
Hypeparathyroidism
Pigmented villonodular synovitis
Osteomalacia
Neurofibromatosis