Table 2.

Characteristic features of giant, multinucleated osteoclasts in bone disorders

Condition	Detached osteoclasts	Osteoid	Osteoblasts	Abnormal marrow	Other features
Long-term therapy with aminobisphosphonates	Increased; approximately 30% apoptotic	Low-to-normal	Low-to-normal	No	Low-to-normal bone turnover
Hyperparathyroidism	No, but rare osteoclast apoptosis might be noted	Increased	Increased	Peritrabecular fibrosis	Prominent, deep resorption cavities
Paget disease	Often, but no apoptosis unless treated with an aminobisphosphonate	Increased	Increased	Fibrosis and increased blood vessels	Mosaic architecture, woven bone
Giant cell tumor	Yes, but no apoptosis	Present in about one-third of cases	Rare	Plump or ovoid-shaped cells interspersed with giant cells	Cyst formation, hemorrhages, mitotic figures
Fibrous dysplasia	Yes, but no apoptosis unless treated with an aminobisphosphonate	Might be excessive	Retracted from the bone perimeter	Long spindle-shaped fibroblasts and loose reticulin fibers	Lesions resembling chinese characters, large osteocytic lacunae, woven bone