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Oral Tumors, Malignant 715

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ORAL TUMORS, MALIGNANT Clinical photographs of a 9-year-old dog with malignant spindle cell sarcoma at
the right mandibular body. A, Rostrodorsal view at right mandible, with tumor located in the area of the third and
fourth premolars (P3 and P4) and first molar (M1). B, Right total mandibulectomy (resected specimen is shown); right
commissuroplasty and crown reduction with vital pulp therapy of left mandibular canine tooth were performed. C,
Same dog presenting for its 2-week re-exam; note sutures at lip skin still in place and an adhesive tape muzzle in
position that limits range of mouth opening postoperatively. D, Dog presenting for its 1-year re-exam. This dog had an
excellent quality of life for 4.5 years postoperatively and died of unrelated causes. (Copyright Dr. Alexander M. Reiter,
University of Pennsylvania.)

• Radiation therapy offers good long-term it can obscure histologic exam of margins PEARLS & CONSIDERATIONS
control for treatment of microscopic disease, of excised tissue and may increase the
but bulky tumors rarely respond well. likelihood of wound dehiscence, which Comments
• Piroxicam 0.3 mg/kg PO q 24h in dogs may can result in the need for further surgical • Incisional biopsy should be performed for
slow the progression of some carcinomas. intervention (e.g., repair of an oronasal larger oral masses. Excisional biopsy may be
Short-term (10 days) use of piroxicam in cats fistula). curative but carries the risk of inadequate
appears to be safe at 0.3 mg/kg PO q 24h. • Sublingual or cervical sialoceles may tumor removal. When submitting excisional
Further studies are necessary to determine occur if transection of salivary ducts is biopsies, request that the pathologist evaluate
long-term gastrointestinal safety in cats. If necessary; these ducts should be ligated if margins for neoplastic cells. Clean margins
prescribed long-term for cancer palliation, transected. according to histologic exam do not rule
the author prescribes 0.3 mg/kg q 48h. out the possibility of recurrence, but animals
Recommended Monitoring with clean margins have a better long-term
Nutrition/Diet • Oral exam to monitor for local recurrence prognosis.
Soft food/esophagostomy tube (p. 1106) if 1 month after surgery and at a maximum • Dental radiography is invaluable for providing
necessary because of inability to prehend or of 6-month intervals thereafter. diagnostic and treatment planning informa-
chew food • Thoracic radiographs and lymph node palpa- tion for oral tumors. Benign tumors tend
tion should be performed every 6 months. to displace teeth that often remain firmly
Drug Interactions seated, whereas more aggressive tumors cause
Piroxicam and other nonsteroidal antiinflam- PROGNOSIS & OUTCOME root and alveolar bone resorption, which
matories may cause extensive gastric ulceration; can manifest as very mobile (floating) teeth.
avoid concurrent use of corticosteroids, and • Median survival time for most malignant Benign tumors may have a smooth layer
consider gastric protectants such as misoprostol. oral tumors after surgical excision has been of reactive bone surrounding the neoplastic
7-12 months. However, when surgeons tissue, whereas a malignant tumor often
Possible Complications obtain clean surgical margins in the absence exhibits destruction of cortical bone, with
• Recurrence of primary tumor; at least 1 cm of of microscopic metastasis, patients can be formation of a classic radiographic sunburst
clinically and radiographically healthy tissue cured. appearance.
surrounding malignant tumors should be • Prognosis for SCC is good if found while • Right or left total mandibulectomy (incorrectly
removed; many locally aggressive tumors still surgically resectable. called hemimandibulectomy) and maxillec-
3
(fibrosarcoma, peripheral nerve sheath • Malignant melanomas > 8 cm (2 × 2 × tomy surgeries carry with them the potential
tumor, malignant melanoma) require even 2 cm) have a high incidence of microscopic for profuse bleeding. Blood type and cross-
wider margins. metastasis at the time of diagnosis. matching may be warranted preoperatively.
• Intraoperative or postoperative bleeding: • Mandibular osteosarcoma has been reported • Sublingual edema seen within 48 hours after
having blood products available is important to have a lower metastatic rate and better mandibulectomy should not be confused
for mandibulectomy and maxillectomy prognosis than appendicular osteosarcoma. with a sublingual sialocele (ranula). Edema
procedures (p. 1169). • Tonsillar SCC in dogs commonly metastasizes usually resolves without treatment.
• Dehiscence of the surgical site: avoid using to regional lymph nodes, with 85% having • Pigmentation is not a reliable indicator of
electrocautery on mucosal edges because regional metastasis at necropsy. tumor type. About 40% of oral malignant

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