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.摘要 1只8岁雌性拳师犬因流涎、口臭及吞咽困难就诊。临床检查发现其舌中三分之一段存在一处大小为3.5×4.0cm的溃疡性肿块。经组织病理学与免疫组织化学检查，确诊为高级别肥大细胞瘤。宠主拒绝接受外科治疗（舌部分切除术），遂采用放射治疗。治疗方案为每日1次、每次300cGy的分割照射，共15次，使用千伏级X线治疗机实施治疗。患犬在第4次治疗后实现肿瘤临床完全缓解，仅出现轻度黏膜炎这一不良反应。治疗期间采用长春碱与洛莫司汀每14天交替给药的全身化疗方案，持续4个月。治疗结束22个月后，该患犬未出现局部复发或转移征象。对于不可切除的肥大细胞瘤，放射治疗联合化疗可作为替代治疗方案，该方案可使侵袭性肿瘤获得完全且持久的缓解，同时保障患犬拥有良好的生活质量。