title: Ameloblastic fibro-odontoma associated with a retained molar in an Oldenburg mare.
abstract: An 11-year-old Oldenburg mare presented with a 3-month history of weight loss and swelling of the posterior right mandible. Physical examination and radiographs showed a soft-tissue mass in the right mandible with foci of mineralization, periosteal proliferation, and a retained molar. The tumor increased in size over several weeks, and the mare was euthanized. On necropsy, a 24 cm × 15 cm × 15 cm firm, white mass had obliterated the posterior right mandible. The mass was multinodular with discrete clusters of blood-filled cystic spaces. Histologically, the mass was composed of neoplastic odontogenic epithelium and pulpal mesenchyme with an accumulation of eosinophilic material resembling dentin or enamel. Microscopic and immunohistochemical staining features of the neoplasm were most consistent with an ameloblastic fibro-odontoma.
authors.affiliation: University of Georgia, College of Veterinary Medicine, Department of Pathology, 501 DW Brooks Drive, Athens, GA 30602, USA. sknowles@uga.edu
authors.forename: Susan
authors.initials: S
authors.lastname: Knowles
authors.forename: Uriel
authors.initials: U
authors.lastname: Blas-Machado
authors.forename: Abigail M
authors.initials: AM
authors.lastname: Butler
authors.forename: Sara E
authors.initials: SE
authors.lastname: Gomez-Ibañez
authors.forename: Michael Q
authors.initials: MQ
authors.lastname: Lowder
authors.forename: Richard A
authors.initials: RA
authors.lastname: Fayrer-Hosken
mesh_terms: D000818:Animals; D005260:Female; D006734:Horse Diseases / Q000473:pathology*; D006736:Horses; D008339:Mandibular Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D008963:Molar; D009808:Odontogenic Tumors / Q000473:pathology / Q000662:veterinary*; D009810:Odontoma / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*