Case report 695: Cementifying fibroma of the proximal end of the tibia.

A case of a cementifying fibroma in the proximal end of the tibia in a 31-year-old woman is presented. The lesion was expanding but well-defined with amorphous central calcification. The unique, calcified, cementum-like particles in a fibrous stroma have been reported in only four previous cases in long bones. The histological and radiographic differences between a cementifying fibroma, bone cysts with cementum, and a true cementoma are discussed. The radiological differential diagnosis of fibrous dysplasia, giant cell tumor, and low grade central osteosarcoma was considered.