Ossifying Fibroma in the Rostral Maxilla of Canis lupus familiaris

Abstract

Background: Ossifying fibroma (OF) is considered a rare occurrence in dogs and presents as a benign neoformation, with a low invasiveness, slow and progressive growth, smooth, firm, globose and pedunculated appearance, originating from cells of the periodontal ligament, its prominence is notable due to the presence of bone formation within the tumor mass. Diagnosis is made by histopathology and intraoral radiography. The recommended treatment is excision of this bone formation, with a good prognosis if removed completely. The aim of this paper was presents a literature review regarding the disease ossifying fibroma, together with a case study describing the diagnosis in Canis lupus familiaris.

Case: An approximately 8-year-old mixed-breed castrated male dog, weighing 7.3 kg,  was treated at the Veterinary Complex of the Centro Universitário Nossa Senhora do Patrocínio (CEUNSP), in Salto city, São Paulo state, Brazil. The patient had a firm, pigmented globose enlargement of the rostral maxilla. The treatment was carried out using the surgical technique of partial rostral maxillectomy under general inhalation anesthesia, performing assertive excision of the entire tumor region and its safety margin, with diagnosis made by macroscopic observation and histopathological examination associated with intraoral radiography, with a good prognosis according to our data which corroborate the literature, with the patient being monitored and no showing signs of local recurrence.

Discussion: The importance of complementary diagnostic tests, such as histopathological and radiographic exams, in the routine of veterinary dentistry is mandatory in order to establish the diagnosis and therapeutic monitoring of Ossifying Fibroma (OF) and in order to discard differential diagnosis like to the fibrous dysplasia, which has similar histopathological findings but can be differentiated through radiographic imaging, which shows the presence of intratumoral bone formation. In the present report, in agreement with the majority of cases described in the literature, the animal showed signs of neoplasms in a context of 4th-stage periodontal disease. It was castrated males are the most affected by this pathology, in addition, they mention that Golden Retriever dogs are the most predisposed to acquiring the lesion, however, the patient in this case was a small mixed-breed dog. Rostral partial maxillectomy under general inhalation anesthesia was performed as the treatment of choice, promoting the absence of recurrence up to the time of this report, in agreement with what has been reported in the literature about the good prognosis of OF when treated early and with adequate excision. It can be concluded that the treatment for ossifying fibroma is surgical and, as it has a benign behaviour, it does not cause metastasis. Monitoring is mandatory for all patients with all oral tumors, as it is a tool to help draw up a therapeutic protocol in the event of recurrence. A better prognosis can be considered for tumors in the rostral region of the mandible, which have easier surgical access for a wider safety margin. Veterinarians need to be aware of how to inspect the oral cavity during routine and emergency care, in order to identify changes in the oral cavity at an early stage. It is worth noting that well-educated carers can also recognize significant alterations in the oral cavity of their animals and consult a veterinarian so that an intervention can be carried out as quickly as possible.

Keywords: dentistry, odontogenic tumors, oral cavity, ossifying fibroma.

Título: Fibroma Ossificante em Maxila Rostral de Canis lupus familiaris

Descritores: cavidade oral, epulides ossificante, maxilectomia, tumores odontogênicos.