PERIPHERAL OSSIFYING FIBROMA: CLINICAL FEATURES, HISTOPATHOLOGY AND TREATMENT
Author: Sanketh DS, MDS
INTRODUCTION AND ETIOLOGY
Peripheral ossifying fibroma(POF) is a tumor like growth occurring quite commonly in the oral cavity and represents a reactive process rather than a neoplasm. It has been referred to by a variety of terms like peripheral cemento-ossifying fibroma, peripheral fibroma with calcification, ossifying fibrous epulis and peripheral odontogenic fibroma. However POF should not be confused for peripheral odontogenic fibroma as the latter is a distinct entitiy and is a rare soft tissue counterpart of the odontogenic tumor, central odontogenic fibroma! In addition, POF is not considered to be the soft tissue counterpart of central ossifying fibroma. The latter is a benign fibro-osseous neoplasm of the jaw bones.
The cause for this lesion appears to be local irritating factors like dental plaque, calculus, ill-fitting prostheses, poorly made dental restorations and micro-organisms and is believed to arise from the periodontal ligament or the periosteum. Researchers also believe that some POFs initially develop as pyogenic granulomas that with time become fibrous and undergo subsequent calcification.
This lesion predominantly occurs in teenagers and young adults with the average age of diagnosis being 10-19 years. Approximately 2/3rds of the cases are reported to occur in females. POF occurs almost equally on both maxilla and mandible, although some reports reveal a slight predilection for maxilla.
POF exclusively occurs on the gingiva and frequently anterior to the molars in the incisor-cuspid region. The clinical appearance is similar to pyogenic granuloma and it appears as a nodular mass on the interdental papilla. Its colour may range from pink to red and the surface of the lesion may be frequently ulcerated. The lesion is either sessile or pedunculated and is not greater than 2cm in size although large lesions have been reported. Some cases have been reported to cause displacement of adjacent teeth.
Microscopy reveals an intact or frequently an ulcerated layer of stratified squamous epithelium. The stroma or the connective tissue is highly cellular consisting of numerous fibroblasts along with delicate collagen fibrils. This lesion is characteristically more cellular than a fibroma and not as vascularised as a pyogenic granuloma, although older POFs may be more fibrous than early lesions. POFs are characterised by the presence of areas of calcification throughout the stroma. Calcifications may be in the form of
a) immature woven or mature lamellar bone,
b) dystrophic calcifications appearing as tiny globules of basophilic masses and
c) ovoid masses of basophilic cementum like material.
Remember that peripheral ossifying fibroma exclusively occurs on the gingiva. And the first set of differentials to be considered when diagnosing a soft tissue lump on the gingiva are Pyogenic granuloma, Peripheral giant cell granuloma and Peripheral ossifying fibroma. An irritational fibroma could also be considered especially with older POFs being firm and pink in clinical appearance. Metastatic tumors, peripheral odontogenic tumors, mesenchymal tumors like hemangioma and squamous cell carcinoma could also be considered.
Local surgical excision is the treatment of choice with submission of the specimen for a microscopic examination. A recurrence rate of approximately 8-16% has been reported, hence care must be taken to excise the lesion down to the periosteum and to scale the adjacent teeth in order to remove any source of local irritation to prevent recurrence.
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OTHER (HACKDENTISTRY) PRACTICE/STUDY RESOURCES