title: Benign and Malignant Proliferative Fibro-osseous and Osseous Lesions of the Oral Cavity of Dogs.
abstract: Ossifying fibroma (OF) and fibrous dysplasia (FD) are benign, intraosseous, proliferative fibro-osseous lesions (PFOLs) characterized by replacement of normal bone by a fibrous matrix with various degrees of mineralization and ossification. Osteomas are benign tumors composed of mature, well-differentiated bone. Clinical, imaging, and histologic features of 15 initially diagnosed benign PFOLs and osteomas of the canine oral cavity were evaluated. Final diagnoses after reevaluation were as follows: OF (3 cases), FD (4 cases), low-grade osteosarcoma (LG-OSA) (3 cases), and osteoma (5 cases). Histology alone often did not result in a definitive diagnosis for PFOL. OF appeared as a well-circumscribed, radiopaque mass with some degree of bone lysis on imaging. Most lesions of FD showed soft tissue opacity with bone lysis and ill-defined margins. Low-grade OSA appeared as a lytic lesion with a mixed opacity and ill-defined margins. Osteomas were characterized by a mineralized, expansile, well-circumscribed lesion. Although histologic features of PFOLs were typically bland, the lesions diagnosed as LG-OSA had some features of malignancy (eg, bone invasion or a higher mitotic index). Treatment varied widely. Of the 10 dogs with benign PFOL or osteoma with known outcome (10/12), 9 showed either complete response (6/10) or stable disease (3/10) after treatment. Of the 2 dogs with LG-OSA with known outcome, 1 showed complete response after curative intent surgery, but 1 patient had recurrence after partial maxillectomy. Definitive diagnosis of mandibular/maxillary PFOL is challenging via histopathologic examination alone, and accurate diagnosis is best achieved through assimilation of clinical, imaging, and histopathologic features.
authors.affiliation: Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA mariasol@vet.upenn.edu.
authors.forename: M
authors.initials: M
authors.lastname: Soltero-Rivera
authors.affiliation: Department of Pathology and Toxicology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: J B
authors.initials: JB
authors.lastname: Engiles
authors.affiliation: Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Reiter
authors.affiliation: Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: J
authors.initials: J
authors.lastname: Reetz
authors.affiliation: Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Lewis
authors.affiliation: Department of Pathology and Toxicology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Sánchez
mesh_terms: D000818:Animals; D001859:Bone Neoplasms / Q000473:pathology / Q000662:veterinary; D004283:Dog Diseases / Q000473:pathology*; D004285:Dogs; D018214:Fibroma, Ossifying / Q000473:pathology / Q000662:veterinary; D005357:Fibrous Dysplasia of Bone / Q000473:pathology / Q000662:veterinary; D009055:Mouth / Q000473:pathology; D009059:Mouth Diseases / Q000473:pathology / Q000662:veterinary*; D009062:Mouth Neoplasms / Q000473:pathology / Q000662:veterinary*; D010016:Osteoma / Q000473:pathology / Q000662:veterinary
keywords: bone neoplasms; canine; fibrous dysplasia; oral cavity; oral pathology; ossifying fibroma; osteoma; osteosarcoma