Cancer lumps on dogs are generally hard and firm to the touch. Most of the time, they are irregularly shaped and can vary from tiny pea-sized bumps to large masses.
While cancer can occur anywhere on a dog's body, pay particular attention to some specific locations, such as around the head, neck, limbs, lower abdomen, and chest.
A lump that has appeared suddenly and is growing and changing shape at a rapid rate can be cancerous. Get it checked by the vet immediately.
If there is a lump that has become ulcerated and has started bleeding or oozes pus, blood, or other fluid, it could be a sign of skin cancer in dogs.