Lamellation in fibrous dysplasia: A clinicopathologic study.

Fibrous dysplasia (FD) is a maturation defect characterized by immature woven bones and stroma. However, especially in craniofacial bones, lamellation can be seen and this is associated with the maturation.To show maturation in FD and discuss the factors that may affect the maturation.Ninety-five FD cases were divided into three subgroups according to the lamellation percentage as Groups 1, 2 and 3 (low, moderate and high lamellation, respectively). Each group was compared in terms of the peritrabecular clefting (PTC), stromal cellularity and the age. The lesions under pressure and the ones that are not were compared in terms of lamellation percentage.A significant statistical difference was found between Groups 1 and 3 in terms of PTC, stromal cellularity, histologic pattern suggesting maturation (p<0.001, p<0.001, p=0.002, respectively).The findings suggested a strong relation between lamellation and maturation. Lamellation was more prominent in the bones under pressure than the others. Considering lamellation as a finding of maturation, it is possible to establish a relation between maturation and pressure. Therefore, future studies should focus on the question if the pressure could be a factor for maturation and it could be used for treating FD.