Long-term survival in a cat with tonsillar squamous cell carcinoma treated with surgery and chemotherapy

Case summary: A 13-year-old neutered female domestic shorthair cat was presented for further investigation of a right-sided cervical mass. Oral cavity examination revealed a unilateral, right tonsillar mass. Following a contrast-enhanced CT scan of head, thorax and abdomen, which showed no clear evidence of distant metastasis, cytology of the cervical mass was consistent with a metastatic retropharyngeal lymph node, and the patient underwent tonsillectomy and lymphadenectomy. The tumour was histopathologically confirmed to be a well-differentiated squamous cell carcinoma with lymph node metastasis, and sequential chemotherapy treatments with carboplatin were administered. The cat underwent a second surgery to treat local recurrence and chemotherapy was continued. Subsequently, multiple lymphadenectomies to remove additional metastatic lymph nodes were performed, followed by adjuvant treatment with doxorubicin. Restaging procedures, performed every 3-6 months did not document any local recurrence nor any local or distant metastasis. The patient was euthanased after developing neoplastic pleural effusion 965 days following tonsillectomy. Relevance and novel information: Tonsillar tumours are rare in cats, but clinical presentation can be similar to that in dogs. Treatment with surgery and chemotherapy, and more importantly multiple lymphadenectomies, may delay the onset of distant metastasis and it should be considered in similar cases to possibly prolong survival.