Partial parotid sialoadenectomy in a horse with parotid ductal carcinoma: Surgical description and case report.

OBJECTIVES: To describe the surgical findings, histopathological features, and long-term outcome for a horse with parotid salivary carcinoma. STUDY DESIGN: Case report ANIMALS: Twelve year old American Quarter Horse gelding. METHODS: The gelding was presented for a 10 x 10 cm swelling below the base of the right ear. Ultrasonographic examination revealed a mass involving the right parotid salivary gland. Incisional biopsy was consistent with parotid carcinoma. The tumor was marginally excised. The lateral wall of the guttural pouch was excised with the mass and was reconstructed with a porcine small intestinal submucosal (SIS) sheet. Cisplatin beads were implanted in the wound bed prior to closure. Firocoxib (0.1 mg/kg orally, daily, every 24 h) treatment was initiated. RESULTS: Postoperative complications included right-sided facial nerve paralysis, difficulty with deglutition of fibrous feeds, and surgical site dehiscence. Wound healing was achieved by second intention. Partial improvement in nerve function was observed within the first 6 months. At 12 months postparotidectomy, no sign of tumor reoccurrence or metastatic disease was present, and the gelding returned to work. CONCLUSION: Partial parotid sialoadenectomy was performed with a favorable long-term outcome. Regional anatomic knowledge is crucial.