Companion Animals

Canine Mast Cell Tumour: Welfare and Management 2026

Mast cell tumours are among the most common skin tumours in dogs with significant welfare implications depending on grade, and treatment outcomes have improved substantially with targeted therapies.

Key Facts

Mast cell tumours account for around 20% of all skin tumours in dogs
Breeds with highest prevalence include Boxers, Labrador Retrievers and Golden Retrievers
Tumour grade determines prognosis: grade 1 and 2 tumours carry much better prognoses than grade 3
Tyrosine kinase inhibitors (toceranib, masitinib) have improved outcomes for unresectable or metastatic disease

Welfare Considerations

Mast cell tumours can release histamine causing local and systemic effects including gastrointestinal ulceration. Welfare priorities include prompt surgical excision with adequate margins for localised tumours, histopathological grading to guide adjuvant therapy decisions, prophylactic H1/H2 antihistamines to manage degranulation side effects, and targeted therapy for inoperable or advanced disease.

What You Can Do

Have any new skin lump on a dog assessed by a vet promptly — mast cell tumours can look benign
Request fine needle aspirate cytology before biopsy for any suspicious skin mass
Ensure wide surgical margins are achieved at first excision if mast cell tumour is confirmed
Discuss tyrosine kinase inhibitor therapy with an oncologist for high-grade or metastatic disease