Ameloblastic fibro-odontoma in a bovine

ABSTRACT

Background: Ameloblastic fibro-odontoma is a benign tumor derived from odontogenic epithelium and mesenchymaltissue, which forms enamel and dentin. It is a rare neoplasm in all species. One of the most common sites for their occurrence is the anterior mandibules. The prevalence of this odontogenic tumor is higher in young animals and only few casesare described in cattle. The purpose of this article is describe the clinical, surgical and the histopathological characteristicof a fibro-odontoma case in a Jersey Cow.Case A 3-year-old Jersey cow was presented with a progressively growing mass in the anterior mandible displacing theincisor teeth. The mass measured approximately 12 cm diameter and there was a focal area of myiasis. The owner reportedweight loss and eating difficulties. The animal was treated with antibiotics for a few weeks but the conservative treatment failed, and the heifer underwent surgical removal of the lesion. The tumor was sent for histopathological evaluationat UFPR-Palotina Pathology laboratory. Microscopically, the excised mass was poorly delimited, and was composed oftumor cells of mesenchymal and epithelial origin which infiltrated and compressed surrounding tissues. Neoplastic cellswere arranged in bundles which multifocally formed dental sacs (dental follicles) of various sizes. These dental sacswere formed by neoplastic ameloblasts, and were surrounded by abundant fibrous connective tissue. The central zone ofthe tumor consisted of a loose, vacuolated neoplastic stellate reticulum. Mitotic figures were rare, and there was moderate anisokaryosis. In some areas, neoplastic ameloblasts surrounded the stellate reticulum. The presence of a sparse,well-organized basophilic extracellular matrix produced presumably by the tumor cells and interpreted as dentin. Thesemicroscopic characteristics led to the diagnosis of an...