Mast cell tumors are the most common malignant skin tumor in dogs, with outcomes ranging from completely curable to rapidly fatal depending on grade, location, and breed, requiring accurate diagnosis and grading.
Mast cell tumors create welfare challenges from multiple directions. The tumors themselves can release histamine causing nausea, vomiting, and duodenal ulcers - symptoms of ongoing systemic illness. High-grade tumors causing rapid metastatic disease bring the progressive deterioration of advanced cancer. Aggressive surgery for low-grade tumors is curative but requires recovery from significant soft tissue surgery. The staging and grading process involves multiple procedures. Dogs with high-grade disease may experience weeks to months of declining health with decreasing quality of life. The welfare-considerate approach involves accurate grading, appropriate treatment planning for each grade, and honest quality-of-life discussions for dogs with aggressive disease.