Oral neoplasia of either benign or malignant type is of growing concern among veterinarians and their clients. This is likely due to the fact that these tumors are becoming more prevalent with our aging pet population. Oral tumors are the fourth most common malignancy reported in dogs, accounting for 3% of all canine malignant tumors, whereas they make up 6% of malignant tumors in cats. The majority of oral "growths" in the dog are benign epulides or gingival hyperplasia. In the cat, these growths are much more commonly malignant than benign.

Generally, the only effective remedy for malignant oral cancers is early, aggressive surgery. This means 2 cm margins around the clinical and radiographic margins of the tumor. In cats and small dogs this is often impossible, especially when the tumor is located deep in the mouth. Therefore, just like in human oncology, early detection and definitive treatment is the key to curing the problem.

Early detection may not occur, as most clients do not examine their pets' mouths often. Client education is worthwhile here, along with improved efforts by clinicians to undertake a thorough oral examination during routine physicals and dental prophylaxis. The most important time to evaluate the oral cavity is during general anesthesia.

Once a growth has been seen, accurate identification requires examination by histopathology, as there are numerous cases of lesions that look benign actually being malignant growths. Veterinarian may dismiss a small soft lump as appearing to be an epulis or hyperplasia, only to have the pet represent a few months later with inoperable cancer. Therefore, all oral masses regardless of appearance should be biopsied for histopathologic examination.

Benign appearing lesion was diagnosed as amelanotic melanoma. Pre-maxillectomy resulted in a complete cure.

The opposite situation also pertains, where a very aggressive appearing growth turns out to be caused by an infectious or immune-mediated disease process. However, if a tumor is diagnosed which does not fit clinical judgment of the case, be sure to discuss it with the pathologist involved. Providing the pathologist with a thorough history is very helpful, as oral tumors are commonly misdiagnosed in both humans and animals. This should include: signalment of the patient, previous biopsy/cytology results, longevity of the growth, radiographic signs of bone invasion (dental radiographs are preferred), and description of the gross appearance and exact location of the tumor.

Patient was presented for euthanasia based on "diagnosis" of squamous cell carcinoma elsewhere. Histopathology revealed eosinophilic granuloma. Patient fully recovered with steroid therapy.


Patient was presented for partial glossectomy for fibrosarcoma of the tongue. Re-biopsy revealed eosinophilic granuloma complex which resolved with steroid therapy.

[Contributed by Dr. Brook Niemiec, DAVDC, Newport Beach, CA]