The histomorphologic spectrum of peripheral ossifying fibroma.

A series of 207 cases of peripheral ossifying fibroma was analyzed both clinically and histologically. Almost 60% of the lesions occurred in the maxilla, and in both jaws more than 50% occurred in the incisor-cuspid region. The lesion was most common in the second decade. Females were affected more frequently than males; the ratio was 1.7:1. The recurrence rate--16%--was relatively high. Histologically, in 66% of the cases the surface epithelium was ulcerated and in the remainder it was intact. The ulcerated lesions were composed of highly cellular fibroblastic connective tissue, whereas in the nonulcerated lesions part of the tissue was more collagenized. Both types contained mineralized products in the form of bone, cementum-like material, and/or a dystrophic type of calcification. The dystrophic calcification was most prevalent in the ulcerated lesions. The mean duration at time of excision for the ulcerated lesions was 5.6 months and for the nonulcerated lesions was 24 months. It is proposed that the ulcerated and nonulcerated lesions represent a spectrum of one lesion with different stages of maturation.