History
-A 9 years old golden retriever was presented to our clinic in Cairo with right nasal canal obstruction with abnormal growth occluding the right side. Abnormal growth “swelling” has a chronic progressive course resulting in respiratory manifestation and excessive nasal discharge.
-Squamous cell carcinoma was highly suspected.
-Computed tomography was recommended to allow visualization of the borders and extent of the tumor.
–Computed Tomography
-Showing abnormal swelling that extends from the nasal opening to the level of the canines
-The swelling completely obstructs the right nasal passage leading to respiratory manifestation
-Mild osteolysis with internasal septum deviation is apparent
Recommendations
-Pre- Canine tooth maxillelctomy is recommended “Nasal planum resection” with postoperative chemotherapeutic plan.
Nasal tumors account for approximately 1% of all tumors in dogs. The most common tumor type is carcinoma with adenocarcinoma being the most common sub-type of carcinoma. Sarcomas comprise most of the remaining tumors with chondrosarcoma and fibrosarcoma being most common.
The most common presenting signs for dogs with nasal tumors include: epistaxis, sneezing and nasal discharge. These signs tend to be chronic and progressive over weeks to months. The signs are typically refractory to antibiotics although some improvement can occur if secondary infection is present. It is important to note that the epistaxis and/or other nasal discharge will most often be unilateral in the case of a nasal tumor.
Many dogs with nasal tumors that occupy a substantial portion of the nasal lumen will also present with stertorous breathing. Less common signs of a nasal tumor include deformity of the nasal, frontal or periorbital bones and if the tumor has breached the calvarium.
Advanced imaging is necessary to investigate for a nasal tumor. the CT scan will allow for visualization of a tumor and identify the extent, location and any bone involvement. The CT scan will also allow for evaluation of the frontal sinuses and other sinus cavities.
If a foreign body or dental root abscess with oro-nasal fistula is present, the CT can be helpful in detecting this, however, foreign bodies are not always clearly identifiable on CT.
Although metastases to the lungs are uncommon for nasal tumors, it is usually advisable to image the chest, especially if the patient is going on to have advanced treatment for the nasal tumor. This can be done with chest radiographs or by imaging the chest with the CT scanner at the same time as the head CT.
Surgical techniques for removal of tumors that affect the nasal planum or the premaxilla have been described. For extensively invasive malignancies, these techniques may be inadequate if used alone to achieve wide surgical margins. An operative technique that combines resection of the nasal planum and premaxilla has been developed for extensive malignant tumors of the nasal planum or premaxilla.
Surgical Tips For Performing Nasal Planum Resection For Squamous Cell Carcinoma
Definition:Nasal planum resection or planectomy is a drastic surgical procedure in the treatment of malignant disease of the nasal cartilage. It involves circumferential resection of the nasal cartilage rostral to the nasal and incisive bone of the maxilla.
-Even though this is considered drastic surgery mainly due to the appearance of the patient post operatively it gives the best chance of resolution in the case of highly invasive squamous cell carcinoma (SCC).
Tip 1. Always discuss the postoperative appearance of the patient after the surgery with the client prior to the surgery. Often people don’t understand that the entire nasal cartilage will be removed and I find it best to show a picture of the post-operative appearance prior to surgery.
Tip 2. Surgery provides the best modality for a clinical cure. However it is considered invasive. Ideally surgery should not be delayed until the SCC has destroyed the entire nasal cartilage.
Tip 3. Thoracic radiographs are often unrewarding in detecting metastasis. Lymph node aspirates are generally more worthwhile to detect metastasis.
The patient is anaesthetised; the rostral maxilla is shaved and prepared for surgery. The patient is then placed in dorsal recumbency with a rigid foam block under the mandible to elevate the head. Patients should always be intubated. The junction between the cartilage and bone is determined.
Tip 4. Masses in the T4 category generally will not respond to a simple planum resection and will require osteotomy of the maxilla. These patients are not candidates for planum resection. If there is any doubt a CT should be performed to determine bone involvement.
Ideally 5mm margins should be taken between healthy and malignant tissue. A 15-scalpel blade should be used and a single cut performed to limit the haemorrhage. The cut is deep through the entire nasal cartilage and the underlying nasal turbinates to the incisive bone of the maxilla. All of this tissue needs to be removed. Once the tissue has been removed fine absorbable suture material is used to suture up the area. This can be performed in a simple interrupted fashion of a purse string like continuous fashion. Generally 5-0 polydioxone should be used. A small section of buccal mucosa and skin should be left ventral to the philtrum if possible. However if this it not possible due to invasion of the SCC this can be easily reconstructed.
Tip 5. I will generally cut one half of the nasal planum then apply a few simple interrupted sutures between skin and nasal mucosa. This limits the haemorrhage and the nasal mucosa slipping into the nasal cavity. I will then remove the other half in similar fashion.
A collar should be placed post surgery, this should be left on for 2 weeks till complete healing. I will generally continue IV fluids for 12 hours at maintenance. A single dose of antibiotics 30 minutes prior to surgery is all that is needed in these patients. Prolonged courses of antibiotics only lead to resistance and should not be given. Good pain control is essential to get these patients eating, buprenorphine is generally sufficient every 6 to 8 hours parentally. These patients need to be encouraged to eat, as smell is a large part of the feline appetite. Warmed tinned food is often a good option.
Tip 6. I will generally send them home with oral Buprenorphine (injectable formulation dosed orally). This will be absorbed through the mucous membranes of the oral cavity. I will administer a single injection the day after surgery of a NSAID once the patient is fully hydrated post surgery. There may be a small amount of bleeding post surgery and there can be increased sneezing in some patients associated with bleeding. This will resolve with time.
Tip 7. The removed section of nasal planum should ALWAYS be sent for histopathological examination even if you are 100% sure your margins are clear.
Prognosis
With clear surgical margins the prognosis is fair to good. Average survival time is around 600 days in the reported cases.2 Generally recurrence is uncommon with surgical treated cases with clear margins. In cases where margins are not clear radiation therapy is recommended as an adjuvant therapy. However patients need environmental management to prevent further exposure to harmful UV radiation and formation of new SCC on non-pigmented areas.
Text Sources
1.https://vet360.vetlink.co.za/surgical-tips-performing-nasal-planum-resection-squamous-cell-carcinoma/
2.http://www.vsecvet.com/nasal-tumors-dogs/
