TOTAL UNILATERAL HEMIMANDIBULECTOMY IN A DOG WITH MELANOMA - A CASE REPORT

Abstract

Oral melanoma is the most prevalent malignant neoplasm of the oral cavity in dogs and is characterized by rapid tissue growth and high metastatic potential. Diagnosis frequently occurs at advanced stages and is established through clinical, imaging, and laboratory examinations. The treatment of choice is surgical excision, which may be combined with adjuvant therapies such as chemotherapy and immunotherapy. The prognosis is generally guarded to unfavorable due to the biological aggressiveness of the disease and its high rate of local recurrence and distant metastasis. This case report aims to describe the diagnosis, surgical management, and clinical outcome of a dog submitted to total left unilateral hemimandibulectomy for oral malignant melanoma. A 15-year-old, ovariohysterectomized, female Shih-Tzu was presented with a history of progressive swelling in the left mandibular region, accompanied by intense halitosis, ptyalism, oral bleeding, and dysphagia. Physical examination revealed a firm, ulcerated nodule on the left mandible. Preoperative assessment included complete blood count, serum biochemical profile, thoracic radiographs, abdominal ultrasonography, and cardiological evaluation, with no findings precluding the procedure. Total left unilateral hemimandibulectomy with ipsilateral submandibular and retropharyngeal lymphadenectomy was performed, followed by layered closure. Histopathological analysis confirmed malignant melanoma with lymph node metastasis. The postoperative period was uneventful, with adequate wound healing, voluntary return to eating, and significant quality-of-life improvement. Five months postoperatively, pulmonary metastasis was detected, leading to humane euthanasia. Total unilateral hemimandibulectomy proved to be a viable and effective procedure for local control of canine oral melanoma, promoting pain relief and quality of life, although the long-term prognosis remains guarded.