Bilateral mandibular odontogenic fibroma (WHO type): Report of a case with 5-year radiographic follow-up

Abstract

Odontogenic fibromas are a rare benign odontogenic neoplasia, characterized by the presence of odontogenic epithelium with an inactive appearance in a cellular fibrous stroma. Histopathologically there are two types of odontogenic fibromas: an epithelium-poor type (simple type) and an epithelium-rich type (WHO or complex type). Depending on its primary location, two variables can be distinguished, one central or intraosseous and one peripheral or extraosseous. Several cases were published in the literature, but always as unique lesions, and when seen in a multiple manner, they were described as hamartomas associated with enamel dysplasia and other dental malformations. The following report describes a case of bilateral WHO-type central odontogenic fibromas in the premolar area of the mandible in a 13-year-old boy, with 5-year radiographic follow-up. The patient showed no clinical evidence of the lesions, just inclusion of the premolars, so the lesions were a radiographic finding. The teeth were extracted together with the lesions and they were sent for biopsy with a presumptive diagnoses of dentigerous cysts. Both samples were examined using routine techniques (hematoxylin and eosin with light microscopy), and a diagnosis of an odontogenic fibroma was made. The samples were stained with picro-sirius red and were examined under polarized light, which confirmed the diagnosis. We present the complete case with 5-year complete radiographic follow-up with the corresponding histopathological and histochemical characteristics.

Epithelium Rich Type Central Odontogenic Fibroma in Maxilla a Case Report and Review of Literature

“…Half of the cases present posterior to the first molar and up to one-third accompany an unerupted third molar [10]. 12% of COF exhibit radiopaque flecks scattered within the lesion [24]. Radiographic features are not pathognomic.…”

“…In Contrast to dental follicle, COF is a destructive lesion with persistent growth. Only 1 out of 57 of COF examined by Ramer et al, has reported to have features of dentigerous cyst [24]. Reviewing the literature, COF can have the following subtypes:…”

“…Then reports have changed to be equal between maxilla and mandible [23]. But updated records tell the opposite of that, being the maxilla is the common site of involvement [24]. Three cases reported in maxilla, two by Silverman and Knight and one case by Hamner and all were thought to be hyperplastic dental follicle [20].…”

“…MRI also can be a useful tool to distinguish COF from other tumor. Hara et al [24], dragged the attention for the benefit of using MRI as a relevant diagnostic tool to distinguish the COF from other odontogenic tumors and cystic lesions. By evaluating:…”

“…Radiographically, COF appear to have varying characteristics divided between unilocular and multilocular appearance with incidence of root resorption compared to desmoplastic type which have three more time to be multilocular appearance [28]. In conclusion, differentiation between both lesions is still difficult but one can consider the diagnosis of COF if it doesn't clearly shows features of desmoplastic fibroma [24]. Desmoplastic fibroma has abundant of collagen fibers separated by spindle-shaped fibroblasts with elongated or ovoid nuclei [12].…”