During the course of grooming, playing with
or handling your cat, you may discover a lump
or bump or or beneath the skin. To learn what it may be, see this table on lumps or bumps on
or beneath the skin.
Abscess: A painful collection of pus at the site of a bite or puncture
wound. Frequently found after cat fights. Forms a firm swelling that becomes
soft with time. Purulent discharge.
Cancer: A lump that indicates cancer is characterized by rapid enlargement;
appears hard or fixed to surrounding tissue; any lump growing from bone; a lump
that starts to bleed; a mole that begins to spread or ulcerate; an unexplained
open sore that does not heal, especially on the feet or legs. The only way to
tell for sure is to remove and study the lump under a microscope. Better to
check out a benign lump than to miss a malignant one.
Epidermal inclusion cyst: A firm, smooth lump beneath the skin. May grow
slowly. May discharge cheesy material and become infected. Otherwise, not
Grubs/Cuterebra: Inch-long fly larvae that form cystlike lumps beneath the
skin with a hole in the center for the insect to breathe. Often found beneath
the chin, on the neck, or along the abdomen.
Hematoma: A collection of clotted blood beneath the skin; often involves
the ears. Caused by trauma. May be painful.
Mycetoma: Mass or nodule beneath the skin with an open tract to the surface
draining a granular material. Caused by a fungus.
Skin papilloma: These grow out from the skin and may look like a wart or a
piece of chewing gum stuck to the skin. Not painful or dangerous.
nodule with overlying hair loss and wet
surface of pus at the site of a puncture wound or break in the skin. Caused by
Any sort of lump, bump, or growth found on or beneath the skin is, by
definition, a tumor, which literally
means a swelling. Tumors are classified as benign when they are not cancer, and
malignant when they are.
This is the most common cause of heart disease in cats
and the most frequent cause of spontaneous death in indoor adult cats. In
cats with this condition, the walls of the ventricles become thick. However,
because the muscle fibers are replaced by fibrous connective tissue (scar
tissue), the thicker heart walls do not translate into increased pumping power.
In fact, the heart is actually weakened as the affected wall of the heart
becomes less elastic and the heart chambers get smaller.
Classically, a benign growth is one that grows slowly, is surrounded by a
capsule, is not invasive, and does not spread. However, there is no reliable
way to tell if a tumor is benign or malignant without removing it and examining
it with a microscope. If the tumor is benign, it won’t come back if it is
Cancers usually enlarge rapidly (a few weeks or months). They are not
encapsulated. They appear to infiltrate into surrounding tissue and may
ulcerate the skin and bleed. A hard mass that appears to be attached to bone or
could be a growth of the bone itself is a cause for concern. The same is true
for pigmented lumps or flat moles that start to enlarge, then spread out and
begin to bleed (melanomas).
A hard gray or pink open sore that does not heal, especially on the feet and
legs, should be regarded with suspicion. This could be a skin cancer.
Any unexplained nodules, bumps, or open sores on your cat should be checked
by your veterinarian. Most cancers are not painful. Do not delay simply because
your cat does not seem to be feeling uncomfortable.
WebMD Veterinary Reference from "Cat Owner's Home Veterinary Handbook"