Fibrous cortical defect (nonossifying fibroma) of the mandibular ramus: report of 2 cases

Fibrous cortical defect, also known as metaphyseal fibrous defect and nonossifying fibroma, among other terms, is a benign, non-neoplastic proliferative process that is relatively common in the long bones of skeletally immature adolescents. Although the lesion is thought to be a developmental abnormality or defect, the exact etiopathogenesis is largely unknown. The lesion has a limited growth potential and good treatment outcome. This process is very rare in the gnathic bones, and only a few sporadic case reports are documented. This article presents the clinicopathologic features of 2 additional cases and reviews the relevant literature in attempt to identify key features and facilitate rendering definitive diagnosis for this rare entity.