Veterinary Society of
Surgical Oncology



  • tumors of nasal cavity represent approximately 1% of all tumors in dogs and less common in cats
  • etiologic factors include exposure to smoke, indoor kerosene or coal combustion and flea spray
  • sex predisposition in cats: male with a male-to-female ratio of 2:1
  • median age: 10 years although cats with non-epithelial tumors may present at an earlier age


  • nasal tumors are malignant in 91% cats
  • 43% of nasal tumors in cats are epithelial (50% ADC and 50% SCC) and 28% LSA (71% B-cell, 17% epitheliotropic T cell, and 12% non-epitheliotropic T cell)
  • 25%-40% of malignant tumors are sarcomas such as FSA, CSA, OSA, undifferentiated sarcoma, rhabdomyosarcoma, HSA, leiomyosarcoma, myxosarcoma, and malignant fibrous histiocytoma
  • nasal LSA is rare in both species, but more common in cats and not associated with FeLV infection
  • other round cell tumors include plasmacytoma, transmissible venereal tumor, MCT, and histiocytoma
  • other nasal tumors include malignant melanoma and paranasal meningioma
  • nasal tumors, regardless of histologic type, are characterized by locally invasive growth
  • metastatic rate is low at diagnosis but reported in up to 50% of dogs at necropsy
  • metastatic sites include lymph nodes and lungs ± bone reported in 2 dogs
  • benign nasal tumors include adenoma (19% of epithelial tumors in cats), basal cell tumor, fibroma, and neurofibroma
  • nasal vestibule is the most common site for feline nasal SCC, malignant melanoma, and basal cell tumor


General Considerations

  • history, clinical signs, survey radiographs, CT, and tissue biopsy
  • hematology and clotting profile to exclude bleeding disorders: platelet count, PCV, ACT, PT, and APTT
  • lymph node aspirates are positive in 10% and thoracic radiographs are usually normal at presentation
  • CSF should be collected if CNS involvement: increased CSF pressure, protein, and rarely cell count are abnormal

Clinical Signs

  • intermittent and progressive unilateral epistaxis ± mucopurulent discharge
  • epistaxis more common with epithelial tumors in cats
  • other clinical signs: sneezing, reverse sneezing, stertorous respiration, dyspnea, facial deformity, epiphora, and neurologic signs (i.e., seizures, behavioural changes, and obtundation) due to direct invasion of cranial vault
  • seizures more common in cats with olfactory neuroblastoma due to extension into the brain
  • mean duration of clinical signs prior to presentation is 3 months
  • DDx: bleeding diathesis, hypertension, bacterial or fungal rhinitis, and developmental anomalies


Survey Radiographs

  • nasal radiographs determine extent of disease, presumptive diagnosis, and locate an area for biopsy
  • views: lateral, dorsoventral, frontal sinus, open mouth oblique, and open mouth ventrodorsal
  • radiographic pattern depends on histologic type, duration, and previous treatment
  • mixed pattern of conchal destruction ± increased soft tissue opacity
  • opacification of the ipsilateral frontal sinus is often due to impaired sinus drainage, but extension of the neoplastic process into the frontal sinus can also occur
  • less defined and more destructive appearance with aggressive nasal tumors
  • early neoplasia is difficult to differentiate from rhinitis
  • unilateral increase in nasal opacity with attenuation or obliteration of normal conchal pattern is characteristic of early epithelial nasal neoplasia
  • radiographic appearance becomes more heterogenous due to progressive conchal destruction with tumor progression and growth
  • nasal septum can be deviated or destroyed by neoplastic process, but this is difficult to assess
  • peripheral signs of nasal neoplasia includes soft tissue swelling, facial bone destruction, and periosteal new bone formation, and these signs are usually associated with highly aggressive neoplasms

Computed Tomography

  • CT is preferred for determination of extent of disease and planning for radiation therapy
  • useful for determining extent of disease and involvement of cribriform plate and orbit


  • trans-nostril technique preferred for core biopsy although rhinoscopic and open techniques also used
  • techniques: punch biopsy, large-bore plastic cannula, curette, or grasping (i.e., melon ball) forceps
  • measure from the external nares to the medial canthus to prevent penetration of cribriform plate
  • mild resistance is usually discernible when tumor tissue is encountered
  • other techniques: nasal wash with fluid retrieval for cytologic examination (usually unrewarding), brush cytology (often non-diagnostic for mesenchymal tumors), and rhinoscopic biopsy (although samples are small and superficial)
  • complications: mild to moderate hemorrhage
  • hemorrhage is usually self-limiting but carotid ligation is occasionally required

Clinical Staging

WHO Staging System

Modified Staging System



  • palliative
  • nasal neoplasia is usually advanced with bone invasion and critical location adjacent to eyes and brain
  • acute and chronic morbidity with dorsal rhinotomy
  • no improvement in survival time with surgery compared to conservative management or surgery and radiation therapy compared to radiation therapy alone
  • principal indication for surgery is rostral nasal tumors (i.e., nasal planum and vestibule)
  • unilateral or bilateral carotid artery ligation may be required to control epistaxis

Photodynamic Therapy

  • photodynamic therapy has been used to treated 1 cat and 3 dogs with nasal tumors using pyropheophorbide-a-hexyl ether as the photosensitizing agent
  • photodynamic therapy is well tolerated with no cutaneous sensitization, but facial swelling is common and resolves within 72 hours
  • clinical signs are controlled for 2 weeks to > 54 weeks

External Beam Radiation Therapy

General Considerations

  • CT is preferred for planning of radiation field and dosing to limit exposure of normal tissue
  • role of surgical debulking prior to radiation therapy is unknown
  • surgical debulking is required for orthovoltage but optional for cobalt and megavoltage radiation therapy
  • dose: 18 fractions at 3 Gy per fraction for 54 Gy total dose
  • accelerated dose: 10 fractions at 4.2 Gy per fraction for 42 Gy total dose


  • oral mucositis, rhinitis, and radiation-induced moist desquamation for 4-8 weeks
  • treatment of oral mucositis includes tannic acid, glutamine (1.3 g/m 2 q 8 hrs PO), and benzydamine
  • ocular changes (i.e., KCS, corneal ulcers, and cataracts) if eyes included in radiation field and dose > 40 Gy


  • intracavitary therapy using radioactive isotopes
  • potential problems include dose distribution and radiation exposure to personnel


Nasal Lymphosarcoma

  • MST 1,397 days for cats with nasal LSA treated with radiation therapy alone
  • MST 151 days for cats with nasal LSA treated with chemotherapy alone
  • MST 337 days for cats with nasal LSA treated with radiation therapy and chemotherapy, with a 12-month survival rate 46%

Other Nasal Tumors

  • mean survival time 382 days to 19 months for cats with non-LSA nasal tumors treated with radiation therapy alone, with 1-year survival rate 44%-63% and 2-year survival rate 17%





Ipsilateral tumor with no or minimal bone destruction


Bilateral tumor with moderate bone destruction


Bilateral tumor with extranasal extension




Unilateral or bilateral tumor confined to nasal passages without frontal sinus involvement


Bilateral tumor extending into frontal sinuses with erosion of any bone of the nasal passage

Back to top