In order to establish the diagnosis and prognosis of tumors of the oral cavity, a comparative study was carried out in 130 dogs considering age, sex, breed, clinical aspects, exfoliative cytology as well as histopathology.

Exfoliative cytology revealed:

100 percent negative for benign non-odontogenic tumors, 97.91 percent negative benign odontogenic tumors and 77.92 percent positive for malignant tumors.

Histopathology showed:

59.23 percent malignant tumors (33.08 percent malignant melanoma, 9.23 percent squamous cell carcinoma, 5.38 percent osteosarcoma, 2.31 percent fibrosarcoma, 2.31 percent angiosarcoma, 1.54 percent malignant mesenchymal tumors, 1.54 percent malignant fibrohistiocytoma, 1.54 percent lymphoma, 0.77 percent leyomyosarcoma, 0.77 percent epithelioid sarcoma and 0.77 percent angiofibrosarcoma); 36.92 percent benign odontogenic tumors (25.38 percent peripheral odontogenic fibroma, 10.0 percent ossifyng fibroma and 1.54 percent odontoma) in addition to 3.85 percent benign non-odontogenic tumors (1.54 percent fibroma, 0.77 percent plasmocytoma, 0.77 percent pilomatrixoma and 0.77 percent giant tumor cells). These results permit us to conclude that exfoliative cytology was an efficient, safe, quick and noninvasive method and coul be used for early evaluation of oral cancer.