Metabolic changes in osteoclasts isolated from children with fibrous dysplasia

Children with fibrous dysplasia have specific areas of local bony overgrowth. The in vitro metabolism of osteoclasts obtained from involved disease areas of two patients with idiopathic monostotic fibrous dysplasia and one patient with polyostotic fibrous dysplasia were compared with osteoclasts isolated from noninvolved bone in the same individuals and normal controls. The osteoclasts from the involved regions formed similar resorption lacunae compared with osteoclasts isolated from both normal and noninvolved bone. Calcium release into the media, a function of cell-mediated resorption, was decreased in involved osteoclasts compared with osteoclasts derived from normal or noninvolved bone (p < 0.05). Osteoclasts from regions of in vivo abnormal growth exhibited normal mineral metabolism in vitro.