Neoplasias of the oral and pharyngeal cavities are relatively common in the dog and cat. They rank as the fifth and seventh most common locations for tumor diagnosis, respectively. The annual incidence of oral and pharyngeal neoplasia in dogs is 20 per 100,000, with malignant melanoma and squamous cell carcinoma (SCC) diagnosed most commonly. The annual incidence rate is lower in cats (11 per 100,000), with the predominant neoplastic types being SCC and fibrosarcoma.,
Predisposing factors in the development of oral neoplasia include the patient's age, gender, breed, size, and pigmentation of the oral mucosa. Geriatric patients are predisposed in general, although 25% of fibrosarcomas have been reported to occur in young, large-breed dogs.Papillary SCC, virus-induced papillomatosis, and undifferentiated malignancies may also be included in the differential diagnosis for young dogs with oral masses., Male dogs have been reported to be at risk for malignant melanoma and fibrosarcoma. Breeds with an increased risk for oral neoplasia include the German Shepherd, Short-Haired Pointer, Weimaraner, Golden Retriever, Boxer, Chow Chow, and Cocker Spaniel., Large-breed dogs have a higher incidence of fibrosarcoma and nontonsillar SCC, whereas small breeds have a higher incidence of malignant melanoma and tonsillar SCC., Dogs with heavily pigmented oral mucosa are predisposed to malignant melanoma.
Malignant oral neoplasms have a guarded to poor prognosis regardless of their size or location in the oral cavity. The prognosis may be affected by the size of the lesion and the patient's age and species. Dogs younger than 6 years of age with SCC mesial to the second premolar have a better prognosis than older dogs with neoplasms in other locations. Cats with oral SCC have a shorter tumor-free interval than dogs regardless of the type of treatment., The most positive prognosis for oral SCC in dogs is attained with both surgery and radiation therapy. The location of SCC in cats is an important prognostic indicator, with rostral mandibular lesions having the longest survival time. In general the prognosis is poor for cats with SCC due to the difficulty of local control and varied response to radiation and chemotherapy. Oral malignant melanoma may be resected locally with tumor-free margins, but regional or distant metastasis usually occurs. Tumor-free margins for oral fibrosarcoma are more difficult to achieve, which makes local recurrence likely. A 1-year survival rate of 71% has been reported for dogs with mandibular osteosarcoma treated with surgery only; another study indicated less favorable results with surgery only, reporting a median survival time of 5.5 months.,
Benign oral neoplasms and odontogenic neoplasms, including epulides, have an excellent prognosis after complete surgical excision.[47-50]