Hybrid peripheral giant cell granuloma and peripheral ossifying fibroma lesion: A rare case report and review of the literature

Hybrid lesions containing a similar component to the giant cell granuloma (GCG) associated with the central odontogenic fibroma (COF) and fibro-osseous lesions have been reported in the literature since 1992; in contrast, peripheral cases are extremely rare. Thus, the purpose of this manuscript is to report a case of a hybrid lesion constituted by peripheral giant cell granuloma (PGCG) and peripheral ossifying fibroma (POsF), emphasizing the clinical, radiographic, histopathological, therapeutic and prognostic aspects of such lesion. In that way, our case presentation comprised a 31-year-old feodermic female patient that presented a large asymptomatic exophytic lesion in the left mandibular alveolar mucosa, radiographically showing an irregular radiopaque area within the soft tissue lesion. An excisional biopsy was performed under local anesthesia. Histopathological analysis displayed a fragment of oral mucosa lined by parakeratinized and atrophic stratified squamous epithelium with ulcerated areas; the lamina propria exhibited dense connective tissue containing numerous inflammatory multinucleated giant cells (MGCs) permeated by fusiform cells, blood vessels, hemorrhage and hemosiderosis; in addition, deposition of trabecular bone matrix intermixed by MGCs, proliferation of fibroblasts and collagen fibers was observed. When this association between PGCG and POsF occurs, the possibility of a PGCG exhibiting bone formation should be rule out. Therefore, the hybrid PGCG and POsF may represent a diagnostic challenge to pathologists, and more cases with histopathologic features similar to our case should be reported in order to elucidate the questionable histogenesis of this lesion.