Mast cell tumors are a type of cancer that originates from mast cells, which are a part of the immune system. These tumors can occur in various locations on the body, including the skin, and are most commonly found in dogs. They can vary in appearance and severity, ranging from benign to malignant forms. Diagnosis typically involves a physical examination, fine needle aspiration, and sometimes surgical biopsy. Treatment options may include surgery, chemotherapy, or radiation therapy, depending on the tumor's grade and location. Early detection and intervention are crucial for improving outcomes in affected animals.