Proliferative, reparative, and reactive benign bone lesions that may be confused diagnostically with true osseous neoplasms.

Diagnostic problems attending intraosseous and parosteal pseudoneoplastic lesions can be radiographic, or histological, or both. Proliferations in this category may contain cellular fibro-osseous or chondro-osseous tissues that are difficult to separate microscopically from those seen in various true neoplasms of the bones. This review considers the clinicopathologic features of fibrous dysplasia, benign fibro-osseous lesions of the jawbones, osteofibrous dysplasia, metaphyseal fibrous defect, giant-cell reparative granuloma, "brown tumor" of hyperparathyroidism, synovial chondrometaplasia, aneurysmal bone cyst, tumefactive chronic osteomyelitis, proliferative Paget disease, and polyvinylpyrrolidone storage disease of bone.