Acanthomatous Ameloblastoma

Also known as: Acanthomatous Epulis — Peripheral Ameloblastoma — Basal Cell Carcinoma — Adamantinoma

Description

Ameloblastoma (Courtesy of Alun Williams (RVC))

This is a benign but locally invasive odontogenic tumour that appears in the gingiva, often surrounding and displacing the adjacent teeth. The lesions have a raised and cauliflower appearance and are slow growing. Eventually the lesions can become very large and involve the jaw bone.

Signalment

Common oral tumour in dogs but rarely occurs in cats.

Diagnosis

Clinical Signs

Include halitosis, oral bleeding, dental disruption or loss, facial or mandibular deformity, excessive salivation, growth protruding from the mouth and rarely dysphagia.

Diagnostic Imaging

Skull radiography may show a soft tissue opacity in the area of the gingiva with lytic invasion of the underlying alveolar bone. If a malignant neoplasm is a diagnostic possibility, thoracic radiography should be carried out to evaluate for lung metastases.

Biopsy

Required for a definitive diagnosis and incisional biopsy is the technique of choice. When undertaking cytological or grab procedures it is more difficult to obtain a representative sample.

Pathology: Islands and sheets of mature odontogenic epithelium within a collagenous fibrous connective tissue stroma of low/moderate cellularity will be noticed. Each of the islands is bounded by a row of tall columnnar cells. These palisading cells exhibit polarisation away from the basement membrane and have cytoplasmic vacuolation. Central cells have a basaloid appearance. The tumour is often infiiltrating into the underlying bone.

Treatment

Surgical resection is the best option with margins of at least 1cm. Radiation therapy may be considered in patients where wide surgical excision is not possible, however there is a risk of malignant transformation of the tumour at a later stage.

Prognosis

Good following complete surgical excision.

Acanthomatous Ameloblastoma Learning Resources
Literature Search Search for recent publications via CAB Abstract (CABI log in required)	Acanthomatous Ameloblastoma publications

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

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