Peripheral Odontogenic Fibroma

Epulis

Typical Signalment

• Most common benign tumour found in the oral cavity in dogs
• Less common in cats
• Seen in dogs of any age but more common in those > 6years old

Description

Peripheral odontogenic fibroma is a benign tumour that arises from the periodontal ligament. It was previously known as a fibromatous epulis and ossifying epulis depending on the degree of mineralization. They present as firm, smooth swellings of the gingiva and are normally indistinguishable from gingival hyperplasia.

Not to be confused with Acanthomatous Ameloblastoma.

Diagnosis

Clinical Signs

• halitosis
• oral bleeding
• dental disruption or loss
• facial or mandibular deformity
• excessive salivation
• growth protruding from the mouth
• dysphagia occurs rarely

Diagnostic Imaging

Radiographs are required to differentiate this benign neoplasm from malignant or locally aggressive lesions. Skull radiographs will evaluate the oral lesion itself and thoracic radiography to evaluate for metastasies (if a malignancy is a diagnostic possibility). Radiographs typically show a soft tissue opacity in the the gingiva region with varying degrees of mineralization. Bone involvement is not a feature of this neoplasm. Radiography cannot be used to differentiate a peripheral odontogenic fibroma from a hyperplastic gingival lesion.

Biopsy

An incisional biopsy is required to obtain a definitive diagnosis

Treatment

An excision of the neoplasm should be performed. The depth of the excision is determined by the location of the origin of the neoplasm at the periodontal ligament. Excision may be at the gingival level or a deep resection involving the extraction of the affected tooth and curettage of the alveolar socket.

Prognosis

Good following surgical resection. Recurrence is common following incomplete surgical resection.

References

• Tutt, C., Deeprose, J. and Crossley, D. (2007) BSAVA Manual of Canine and Feline Dentistry (3rd Edition) BSAVA

• Merck & Co (2008) The Merck Veterinary Manual

From Pathology

Canine Epulis (Courtesy of Alun Williams (RVC))

• aka: Fibromatous epulis of periodontal ligament origin

Neoplastic

• 17% of cases.
• Proliferation of fibrous tissue with variety of osteoid, cementum or dentine-like material.
• Isolated strands or islands of odontogenic epithelium always present (ie: suggesting induction of connective tissue by the epithelial cells).
• The stroma contains neoplastic fibroblasts, with varying cellularity.
• The overlying epitheluim is normal.

With thanks to Andrew Jefferies (Cambridge) and Alun Williams (RVC) for providing access to their lecture materials

J Comp. Path. 1992 (106), 169-182 The Histological Nature of Epulides in Dogs F. J. M. Verstraete*, A. J. Ligthelmf and A. WeberT. ... review of 154 oral 'epulis' from dogs reviewed with the current (at the time) human literature.