Periosteal ossifying fibroma of the palate.

An unusual case of the ossifying fibroma of a 54-year-old woman is reported. Clinically the lesion appeared as an exophytic mass on the hard palate and apparently originated outside of bone. Histologically the resected tumor is well encapsulated and made up of a richly cellular fibroblastic stroma containing foci of mature bone with a predominantly lamellar structure. While the possibility exists that the lesion is reactive, it appears to be a true neoplastic growth and a purely soft tissue process arising from the periosteum of the palate. Thus, we proposed the term periosteal ossifying fibroma for this distinct lesion in order to distinguish it from the common peripheral ossifying fibroma.