On osteitis deformans (Paget's disease) and its relation to osteitis fibrosa and osteomalacia

Woven bone overview: structural classification based on its integral role in developmental, repair and pathological bone formation throughout vertebrate groups

“…Early observation of the phenomenon Knaggs (1925) recognised that intramembranous bone formation involves two different cell populations. Discussing pathological bone formation in osteitis deformans (Paget's Disease), Knaggs observed that, once original bone disappear, there is "the substitution of a vascular connective tissue (osteogenic tissue) in place of it and its intertrabecular marrow and the formation of new bone from this connective tissue, in the first instance always by metaplasia……The term 'metaplasia' is used here to distinguish bone formation direct from the connective tissue from that which is associated with rows of osteoblasts.…”

“…Paget's disease of bone (osteitis deformans) occurs in adults, generally 50 years old or older. Histopathological descriptions have shown woven bone formation early in the active stages of the disorder, although eventually the predominant findings are osteoclastic bone resorption and synthesis of lamellar bone with a mosaic pattern (Dickson et al, 1945;Freund, 1929;Jaffe, 1933;Knaggs, 1925;Meunier et al, 1980;Schmorl, 1932;Seitz et al, 2009). Highly cellular collections of woven bone are prominent in benign bone tumours and other pathological bone-forming lesions such as osteoid osteoma, within the cellular fibrovascular central nidus, osteoblastoma, where the slow growing disorder allows for formation of SOBLs and lamellar bone on woven deposits (Mirra et al, 1989;Czerniak, 2016b), fibrous dysplasia (Czerniak, 2016c), secondary hyperparathyroidism (Krempien et al, 1975) and chronic osteomyelitis (Mirra et al, 1989).…”