Skin tumours are the most common tumours in dogs, encompassing a wide spectrum from benign fatty lumps to aggressive malignant masses. Early recognition and appropriate management significantly affects welfare outcomes.
Lipomas (benign fatty tumours) are extremely common in middle-aged to older dogs—soft, movable, and rarely requiring treatment unless causing discomfort through location. Mast cell tumours (MCTs) are the most common malignant skin tumour in dogs, with behaviour ranging from benign Grade I to aggressive Grade III. Sebaceous adenomas, histiocytomas (self-limiting in young dogs), and melanomas complete the common skin tumour spectrum. Any new or changing skin lump warrants veterinary assessment.
Fine needle aspiration (FNA) cytology provides rapid, minimally invasive initial assessment. Histopathology of excised tissue provides definitive diagnosis and grading. Mast cell tumour grading (Patnaik or Kiupel two-tier systems) guides treatment planning and prognosis. Staging investigations for malignant tumours (lymph node aspiration, chest radiographs, ultrasound) assess metastatic disease before surgery.
Wide surgical excision is the cornerstone of treatment for most malignant skin tumours. Clean margins reduce recurrence risk. Mast cell tumour surgery requires appropriate margin planning based on grade and location. Pre-operative antihistamine treatment reduces histamine-related surgical complications. Owner education about monitoring for recurrence supports ongoing welfare monitoring.
Toceranib (Palladia) is a tyrosine kinase inhibitor licensed for mast cell tumours in dogs, providing medical management when surgery is not possible. Radiation therapy treats gross or microscopic residual disease after surgery. Corticosteroids and antihistamines manage MCT-related symptoms. Palliative care focuses on comfort maintenance when curative treatment is not pursued.