Hedgehogs unfortunately are highly prone to cancer, especially as they age, with one study reporting over two-thirds of hedgehogs over the age of 3 having cancer. Cancer has been reported in many areas of the body, but is commonly found in the mouth, skin, and female reproductive system. Tumors are often malignant and can carry a poor prognosis, especially without treatment. Early identification will allow for optimal treatments to be implemented and improve long-term prognosis.

Guinea pigs can get a wide variety of masses, growths, and bumps on their bodies. Although we cannot diagnose a mass just by looking at or feeling it, there are some more common masses that occur.