Metaphyseal fibrous defects.

Nonossifying fibromas and fibrous cortical defects are the most common benign lesions of the skeletal system. They are frequently detected incidentally on radiographs taken for an unrelated reason. The diagnosis is routinely made solely on the basis of the history, physical examination, and radiographic appearance. The incidence of multifocal nonossifying fibroma is typically underestimated in patients initially found to have a solitary lesion; the use of a limited skeletal survey rather than bone scan may help detect multifocal lesions in this population. Small, asymptomatic lesions may be followed over time using serial radiographs. Incisional biopsy, curettage, and bone grafting are indicated for large lesions that raise concern for impending pathologic fracture, for lesions that have become painful, and for lesions whose characteristics prevent a definitive radiographic diagnosis. Pathologic fractures involving these lesions should be treated with cast immobilization until the fracture has healed, followed by biopsy, curettage, and bone grafting.