What is peripheral ossifying fibroma?
Peripheral ossifying fibroma is a benign swelling of the gum, most commonly seen in teenagers and young adults. It is derived from cells of the periodontal ligament and is usually classified as a reactive hyperplasia but sometimes as a benign neoplasm. There was considerable confusion in the terminology used in the literature until it was distinguished from peripheral odontogenic fibroma in a recent WHO classification. It is sometimes also called peripheral cemento-ossifying fibroma but is quite distinct from the central cemento-ossifying tumour of bone.
Who gets peripheral ossifying fibroma?
Peripheral ossifying fibroma is a fairly common lesion, representing 1-3% of all oral biopsies in most series. It has been reported from birth to old age, but peaks in the teenage years. It is rare in children in relation to primary dentition (milk teeth) and incidence declines after the age of 30 years. Together with a female predominance, this suggests a hormonal influence on its development. Trauma or irritation caused by dental restorations or prostheses, plaque under the gum or calculus are also believed to play a role.
Peripheral ossifying fibroma occurs only on the gums, developing between the teeth (interdental papilla). It is seen most commonly in the upper jaw towards the front. The most common site is related to an incisor or cuspid tooth.
It can be:
- red or pink in colour
- a smooth or pebbled irregular surface
- ulcerated or not
- a broad base limpet-like attachment or less often on a short stalk (pedunculated)
- small, but very large lesions have been reported
The most common presentation of a peripheral ossifying fibroma is as a slow growing, ulcerated, red, outward growing lump less than 2cm in diameter in an adolesecent. It can reach a considerable size quite quickly, but there is often a delay of months or years before presenting for treatment, depending on the degree of discomfort, aesthetic appearance and development of ulceration.
Clinically it can be difficult to distinguish from other common lumps in the mouth such as pyogenic granuloma, oral irritation fibroma, giant cell fibroma or peripheral giant cell granuloma.
How is peripheral ossifying fibroma diagnosed?
Because of its clinical similarity to commoner lesions in the mouth, it is almost always diagnosed on biopsy and pathology examination. The histology is characteristic with bone, cement or calcium deposits in cellular connective tissue. X-rays rarely show involvement of the underlying jaw bone.
The peripheral ossifying fibroma should be completely excised and sent for histology examination. Extraction of teeth is rarely required. In addition, any predisposing causes should be treated such as plaque or irritation from a dental prosthesis.
Unusually for benign lesions, the recurrence rate is high, up to 20%, occurring on average 12 months following initial excision. Therefore regular follow-up is required.
If surgery is not performed the lesion continues to grow and may cause destruction of nearby bone.