Giant-cell reparative granuloma of the hand and foot bones.

Giant-cell reparative granuloma (GCRG) is an uncommon benign reactive intraosseous lesion. It occurs in the skull, jaw, hand, foot, and facial bones and rarely in other skeletal sites. It is a solitary, lytic, expanded lesion and infrequently may extend into the surrounding soft tissue. Histologically, it is composed of fibrous stroma with spindle-shaped fibroblasts, multinucleated giant cells, and inflammatory mononuclear cells. Areas of hemorrhage are uniformly present. It may be difficult to distinguish this entity from an aneurysmal bone cyst, giant-cell tumor, or brown tumor of hyperparathyroidism because of roentgenographic and histologic similarities. Accurate diagnosis is essential for appropriate treatment; serum calcium, phosphorus, and parathyroid hormone levels should be measured. Curettage and bone graft are effective treatments for both primary lesions and recurrences. Second recurrences are rare.