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Diseases of musculoskeletal system. By Dr. Abdelaty S hawky Dr. Gehan Abdel monem. Paget's disease of bone. Paget's disease of bone ( osteitis deformans ) is a localized, although sometimes multifocal, skeletal disorder of unknown cause.
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Diseases of musculoskeletal system By Dr. AbdelatyShawky Dr. Gehan Abdel monem
Paget's disease of bone (osteitisdeformans) is a localized, although sometimes multifocal, skeletal disorder of unknown cause. • Is an acquired disorder of bone growth and remodelling. • It usually occurs after the age of 40, increases in incidence with aging, and has slight male preponderance.
The skeletal involvement may be limited to a single bone (monostotic) or affect many bones (polyostotic), notably the pelvis, femur, tibia, spine, and skull. • The affected bones may be weakened by resorption or enlarged by bone formation although defective, new-bone formation. • In the final stage of the disease, dense bone is formed, but it is poorly organized and predisposed to fracture and deformity.
* Etiopathogenesis: Is a disorder of bone remodeling. • Increased numbers of osteoclasts initiate the remodeling abnormality with increased bone resorption at affected sites. Coupled with areas of new bone formation, with the deposition of architecturally disorganized new bone. • As a consequence of this localized increase in bone turnover, there is a characteristic radiographic appearance of areas of osteolysis juxtaposed areas of new bone formation.
There is marked frontal bossing in this patient with Paget disease. Involvement of the skull in Paget disease can lead to cranial nerve compression, nerve deafness, optic atrophy
* Histopathology: • The bone changes are divisible into three phases defined radiologically: the osteolytic phase, the mixed osteolytic and osteoblastic phase, and a final osteosclerotic phase.
Osteolytic phase: In this section of bone, a multinucleated osteoclast is seen actively resorbing the surrounding bone
* Complications: • Pathological fracture of affected bones. • Hyperdynamic circulation caused by bone hypervascularity, resulting in high-output left ventricular failure; • Neoplastic transformation into bone sarcoma: most commonly, osteogenic sarcoma; less often, fibrosarcoma; and, rarely, giant cell tumor.