Oral tumours

• Oral tumours - overview

  Tumours can arise from bine, teeth or soft tissue structures of the lower (mandible) or upper (maxilla) jaw, or the tongue or the pharynx.

  Most tumours of the oral cavity are malignant:

  • Malignant melanoma and squamous cell carcinoma most common in dogs.
  • Squamous cell carcinoma most common in cats.

  Other malignant tumours include:

  • Fibrosarcoma
  • Osteosarcome
  • Multilobular osteochondrosarcoma
• Oral tumours - melanoma and amelanotic melanoma

  Melanotic melanomas look dark, if there is no pigment then it is amelanotic melanoma. The way the tumour behaves dictates how you want to treat it. There is a vaccine for melanoma tumours, but you will have to debulk the tumour first.

  
• Oral tumours - squamous cell carcinomas in dogs and cats

  Likely to bleed, can exfoliate quite well, can get a diagnosis through an impression smear and the ones that are eroded.

  Lesions in the cat can be benign (stomatitis lesions in the cat look quite similar to this). The treatment is radiotherapy and also possibly surgery in the fist, follow up adjunctive therapy is radiotherapy as the tumour is very radio-sensitive.
• Oral tumours - mandible and maxillary fibrosarcoma

  Can’t really differentiate these, could be amelanotic melanoma or benign. Have to send these to the lab to find out what they are is it will dictate you surgery.

  
• Oral tumours - Maxillary and mandibular osteosarcoma

  Anything breaking through like the one on the left is worrying, very unlikely to be a benign lesion. Can be invasive and infected or could be simple and just involve the mucosa.

  
• Oral tumours - clinical signs

  Presence of a mass in the oral cavity, can get changes of confirmation in the face depending on where the tumour is. Increased salivation, blood in the saliva, odorous breath. Swelling on the face or bulging of the eye (exopthalmos) - maxillary tumours may grow into the ocular cavity and press on the eye.

  Bloody nasal discharge. Difficulty eating or pain on opening the mouth, weight loss and enlarged lymph nodes in the neck region.

  Loose teeth, especially in aniMacs with generally good teeth, Amy be indicative of cancer-induced bone loss, especially in cats.
• Oral tumours - Diagnositics

  Physical exam - concomitant problems, size and site of oral mass, evaluation of regional lymph nodes.

  Blood tests

  FNA - often non-diagnostic as requires the lesion to exfoliate.

  Core biopsy - histopathology (bony lesions might prove difficult to obtain representative sample).

  Imaging of the skull

  • Conventional radiography, CT scan.

  Staging - conventional radiography, if you don’t have CT could do dental radiogrpahs.
• Oral tumours - treatment options

  Treatment options depend on the location of the tumour and on the type of tumour - benign tumours excised with 1cm margins, malignant tumours excised with 2-3cm margins.

  Mandibulectomy - taking away some of the lower jaw.

  Maxillectomy - taking away some of the upper jaw.

  Immunotherapy for melanoma in dogs.
• Surgical aftercare of oral surgery

  Most animals discharged 2-5 days after surgery, depending on the level of surgery, comfort and ability to eat soft food.

  Return for re-check 7-10 days post-op.

  Restrictions:

  • Analgesia - can do local nerve blocks.
  • Antibiotics
  • Restrictive collar to prevent self-traumatisation.
  • Limited exercise.
  • Soft canned food or soaked kibble for 2-3 week post-op.
  • No chews, raw-hide or chewing toys for at least 3-4 weeks post-op.
• Post-op complications of oral surgery

  Incision breakdown requiring further surgery to repair. Bleeding from the nose following maxillectomy. Increased salivation - may persist for some weeks.

  Mandibular drift following Mandibulectomy.

  Difficulties - usually not a problem in dogs but a common problem in cats.

  Recurrence of tumour.
• General outcomes or oral tumour surgery

  Tumour type and staging dependant.

  • Fibrosarcoma continues to have high local recurrence rebate requiring adjunctive radiation therapy or further surgery.
  • Benign tumours may be cured as long as clean margins have been acheived.