Causes
Many different types with different causes. Age, breed, sun exposure (tumours in areas of pale skin with little hair) and genetics all play a part.
Diagnosis
Fine-needle aspirate (cytology) or biopsy. You can NEVER tell whether a lump is benign or malignant just by looking at it or feeling it.
Treatment
Small benign lumps that cause no problems are sometimes just monitored; those that grow or cause discomfort are removed. Malignant tumours require surgery with clear margins and, depending on the type, additional treatment.
Prevention
Sun protection for animals with pale skin and little hair, and regular skin checks.

