Peripheral ossifying fibroma: A 20-year retrospective study with focus on clinical and morphological features

Abstract

Background: Peripheral Ossifying Fibroma (POF) is a reactive hyperplastic lesion that exclusively occurs in the gingiva and is characterized by the deposition of dystrophic calcification, cementum-like tissue, and immature and mature bone within the connective tissue. The objective of the present study was to perform a retrospective analysis of clinicopathologic features of POF.

Material and methods: Clinical and histopathological data were obtained from biopsy records and histopathological reports from a Brazilian reference service in Oral Pathology (1999 - 2020). Morphological analysis was performed to evaluate features related to the mesenchymal component, inflammatory infiltrate, ulceration, and mineralized tissue.

Results: A total of 270 POFs were diagnosed during the study period. A higher frequency was observed in females (71.9%) between the third (22.9%) and fourth (23.3%) decades of life. The anterior upper gingiva (29.1%) was the most affected region. Mature (86.7%) and immature (52.6%) bone tissue were the most frequent. There was a significant association between immature bone deposition and lesions with size ≤ 1.7 cm (p = 0.041); immature bone and cement-like tissue deposition with an evolution time ≤ 16 months (p < 0.001); deposition of immature bone and mesenchymal hypercellularization (p < 0.001); deposition of dystrophic calcification and the presence of ulceration (p < 0.001).

Conclusions: The clinical characteristics corroborate the findings in the literature. The heterogeneous distribution and quantity of mineralized tissues found in the analyzed cases support the theory that the different mineralized tissues constitute a spectrum of clinical maturation of POF.

Figure 1

Clinical aspect of peripheral ossifying fibroma - Nodular and pedunculated lesion in anterior upper gingiva, exhibiting erythematous areas.

Figure 2

Histopathological features of the peripheral ossifying fibroma (hematoxylin and eosin) - Lesions showing deposition of (A - 1000 µm) mature bone, (B - 100 µm) immature bone, (C - 200 µm) cementum-like tissue, and (D - 50 µm) dystrophic calcification. Bone tissue deposition in (E - 100 µm) hypercellularized and (F - 50 µm) hypocellularized areas. Chronic inflammatory infiltrate close to mineralized tissue (G - 200 µm). Ulceration (H - 200 µm).

Figure 3

Spearman's rank correlation matrix among the type of mineralized tissues. Green represents a positive correlation and red is a negative correlation, as shown in the color key (* represents a statistically significant result).