There are many different types of masses or tumours that can occur in our pets. The tumours that are seen can be benign or malignant. Common benign tumors include lipomas, non-viral papillomas, sebaceous gland adenoma, and perianal gland adenomas. Frequently seen cancers include lymphoma, melanoma, mast cell tumors (which are considered to be potentially malignant, even though they may have benign behavior), and osteosarcoma (bone cancer). Certain breeds are more likely to develop particular tumors, larger ones especially. The Golden Retriever is especially susceptible to lymphoma, with a lifetime risk of 1 in 8. Boxers and Pugs are prone to multiple mast cell tumors. Scottish Terriers have eighteen times the risk of mixed breed dogs to develop transitional cell carcinoma, a type of urinary bladder cancer. Commonly the recommended treatment for a tumour is surgical removal, especially if the tumour is found to be cancerous. Surgery is often curative for these types of cancer.