Long‐term survival in a dog with high‐grade tracheal mast cell tumour treated with surgical excision and chemotherapy

Abstract A 10‐year‐old, female, spayed Siberian Husky presented for a suspected tracheal mass. Computed tomography showed a mass lesion originating from the left caudal cervical tracheal wall. No evidence of systemic involvement was identified. Initial incisional biopsy histopathology was consistent with a high‐grade mast cell tumour. Surgical excision of the mass via tracheal resection and anastomosis was performed. Histological findings were compatible with a high‐grade mast cell tumour, excised with 3.5 mm margins. An eight‐dose course of vinblastine was pursued post‐operatively; gross subcutaneous recurrence was noted 9.5 months post‐operatively, which responded favourably to toceranib. The patient re‐presented to our emergency room in status epilepticus 16 months post‐operatively, and the patient was euthanased at that time. Based on this clinical outcome, with proper treatment, certain patients with tracheal mast cell tumours may achieve better outcomes than historically documented.