Treatment of a canine high grade lingual mast cell tumor with radiation therapy and chemotherapy: case report

ABSTRACT An 8 year old female boxer was presented with salivation, halitosis and dysphagia. In the clinical examination, an ulcerated mass in the middle third of the tongue was observed, measuring 3.5 x 4.0cm. Histopathology and immunohistochemistry the confirmed diagnosis of a high-grade mast cell tumor. Surgical treatment (partial glossectomy) was declined by owner, and radiotherapy was indicated. The protocol consisted of fifteen daily fractions of 300 cGy each. The equipment used was an orthovoltage unit. The tumor had complete clinical remission after the fourth session, and mild mucositis was the only side effect observed. Systemic chemotherapy was performed with vinblastine and lomustine, alternated every 14 days, during four months. There is no evidence of local recurrence or metastasis in this patient twenty-two months after treatment. The combination of radiation therapy and chemotherapy can be considered as an alternative therapy in cases of unresectable mast cell tumors. It led to complete and durable remission of an aggressive tumor, with great quality of life.