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Tumors of the Nose and Paranasal Sinuses |  |
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Tumors of the nose and paranasal sinuses account for 1-2% of all canine or feline tumors. The incidence in dogs is twice that in cats; incidence is also higher in males of both species than in females. The mean age at time of diagnosis is 10.5 yr for dogs and 12 yr for cats. In dogs, 80% of these tumors are malignant, and 60-70% are carcinomas, of which adenocarcinoma is the most common. In dogs, the ethmoturbinates tend to be the site of
predilection. Dolichocephalic and mesocephalic breeds appear to be at higher risk than brachycephalic breeds. In cats, 90% of nasal tumors are malignant, the most common being carcinomas and lymphomas. Tumors of the nose and paranasal sinuses typically are very invasive locally and metastasize infrequently; metastasis is more likely in carcinomas and usually occurs late in the disease. Common sites of metastasis are regional lymph nodes, lungs, and brain. Invasion of the paranasal
sinuses tends to be greater in dogs than in cats. In general, if untreated, survival is 3-5 mo after diagnosis. |
| Chronic nasal discharge is the most common clinical finding; it may be mucoid, mucopurulent, or serosanguinous. Initially, discharge is unilateral but often becomes bilateral. Periodic sneezing, epistaxis, and respiratory stertor may occur. Facial and oral deformities result from destruction of bony or soft-tissue sinonasal structures. Retrobulbar extension of these tumors results in exophthalmos and exposure keratitis. Secondary epiphora may occur if the nasolacrimal duct is
blocked. Late in the disease, CNS signs (eg, disorientation, blindness, seizures, stupor, and coma) may develop if the tumor extends into the cranial vault. |
| Diagnosis is based on history and clinical findings and elimination of other causes of nasal discharge, sneezing, or facial deformation. Nasal radiographs or computed tomography typically show increased density of the nasal cavity and frontal sinuses as well as evidence of bone destruction. Computed tomography is vastly superior to plain radiography in diagnosis of chronic nasal diseases. Definitive diagnosis is based on biopsy of tumor tissue. |
| Treatment largely depends on tumor type and extent of disease. The treatment of choice for canine nasal adenocarcinoma is radiation therapy. Aggressive surgical excision, chemotherapy, radiation therapy, or combinations for other tumor types afford a more favorable prognosis when diagnosis is made early. |
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