Desmoplastic fibroma (fibromatosis) is rarely seen a primary tumor of bone. Its occurrence as a central lesion in the jaws is even more uncommon. It is rare tumor of bone, especially in the mandibule. In march 2004, a 15 year-old boy presented, with a 4 month history of gradual enlargement of the right mandibule. Painless intraoral and extraoral swelling, the cortical plate of bone overlying the lesions is expanded with thinning, erosion, and infiltration into the surrounding tissues. The lesion is similar to the one described on the articule.