A noninductive tumor of odontogenic epithelium occurs within the tooth bearing regions of the jaw in dogs and fits the conventional definition of ameloblastoma, which is distinct from, and less common than, canine acanthomatous ameloblastoma. In order to clarify the clinical and radiological features of this uncommon odontogenic tumor in dogs, we performed a retrospective study of 20 dogs that were diagnosed between 2007 and 2015. Follow-up information was obtained for 17 of 20 dogs. The study group of dogs showed no apparent age, breed, or gender predilection. Conventional ameloblastoma is typically slow growing, well demarcated, and locally destructive. Tumors most commonly occurred as a mass or focal bony swelling within the maxilla (13/20) or mandible (7/20). Based on cases with available diagnostic imaging, as either dental radiographs or computed tomographic images, the tumors were usually intraosseous and caused mixed lytic/proliferative bone changes. Nevertheless, conventional ameloblastomas did not aggressively infiltrate adjacent tissues and recurrence was not observed within the study group, even in patients with narrow surgical margins or treatment by cyst enucleation.

Lateral periodontal cysts (LPCs) are odontogenic epithelial cysts composed of nonkeratinized epithelial cells that are in the category of developmental cysts, rather than inflammatory cysts. Lateral periodontal cysts are rare both in people and domestic animals; they are associated with vital teeth and located lateral to a tooth root. Lateral periodontal cysts are typically asymptomatic lesions that are characterized radiographically as a unilocular lucency with well-defined corticated borders. Canine acanthomatous ameloblastoma (CAA) is the most common odontogenic neoplasm in dogs and rarely presents as a cystic lesion. This case report describes the diagnosis and treatment of a cyst that occurred as a swelling apical to a gingival mass that was diagnosed histologically as CAA. Surgical management by conservative gingivectomy, cyst enucleation, and bone grafting was an effective treatment in this patient.

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