Benign tumors are proliferations of cells that do not invade other tissues or spread to other locations. They are only dangerous when growing in a confined space, like in the head where they may compress the brain. They may need removal if they inhibit any important function or if they become damaged and bleed or become a nuisance. Some common benign tumors are listed below. Lipomas are benign tumors of fat cells uncommonly found under the skin in cats. These tumors are only a problem when they get very large or when they are in a location that interferes with the animal's movement.
Perianal adenomas are found under the tail in the skin next to the anus. They occur most commonly in males that have not been neutered. Your veterinarian will probably recommend neutering at the time the mass is removed to prevent future tumors. Fortunately, the malignant counterpart of this tumor, the perianal adenocarcinoma, is rare.
An abscess is a collection of inflammatory cells (white blood cells) that have been drawn to an area within or under the skin by the stimulation of an infectious agent (fungus or bacteria).
A hematoma is a blood filled space that can be found under the skin and is usually caused by trauma or by a defect in the clotting system.
Hives. When a cat has an allergic reaction, specific cells will release chemicals that cause swelling and redness in the skin.
A cyst is a space within or under the skin that is filled with fluid or cellular debris. Cysts are usually caused by abnormalities of skin glands.