ABSTRACT
The oral cavity is the entry point of the gastrointestinal tract. It is where digestion begins with mastication of ingesta, which is mixed with salivary enzymes and passed through the oropharynx to the esophagus. The oral cavity is most commonly sampled due to the presence of ulcerative lesions and/or masses. The presence of oral masses is one of the most common reasons for cytologic examination of the oral cavity. Melanoma is the most common malignant oral tumor of the dog. The neoplastic cells are of neural crest origin and, as such, can have a pleomorphic appearance, exhibiting morphologic features of both epithelial and mesenchymal cells. Squamous cell carcinoma is the second most common oral neoplasm in dogs and the most common oral cancer in cats, where it often occurs in the frenulum of the tongue. Oral fibrosarcoma is the third most common oral tumor of the dog and the second most common oral tumor of the cat.
