Surface tumors are common in cats. It is often impossible to
determine whether a surface tumor is benign or malignant by appearance alone.
The only conclusive way to make a diagnosis is by biopsy, a procedure in which
tissue or cells are removed by your veterinarian and examined under a
microscope by a veterinary pathologist.
For small tumors, it is best for your veterinarian to remove the growth and
present the entire specimen to the pathologist. For tumors larger than 1 inch
(25 mm) across, it may be advisable for your veterinarian to obtain a tissue
sample by fine needle aspiration. In this procedure, a needle connected to a
syringe is inserted into the tumor and cells are obtained by pulling back on
the plunger. Alternatively, the vet can use a cutting needle to obtain a core
sample. An open biopsy, in which an incision is made, is preferred for
suspected sarcomas and tumors that present diagnostic problems for the
Toxoplasmosis is a disease caused by the parasite Toxoplasma gondii, which can be found in garden soil and raw meat. Cats can get toxoplasma infection by killing and eating infected prey. The disease can also be passed on from cats to humans.
Epidermal inclusion cysts, also called sebaceous cysts, are benign tumors
that arise from glands found beneath the skin. They can occur anywhere on the
body. Although less common in cats than in dogs, they are still the most common
surface tumor in cats.
A sebaceous cyst is made of a thick capsule that surrounds a lump of cheesy
material called sebum. It may grow to 1 inch (25 mm) or more. Eventually, it is
likely to become infected and will have to be drained. This sometimes leads to
Treatment: Most cysts should be removed. Cysts can often be removed by
electrocautery or cryotherapy. At the very least, sedation and a local
anesthetic will be required, and many cats may need general anesthesia.
Warts and Papillomas
These growths are not nearly as common in cats as they are in people. They
tend to occur on the skin of older cats. Some are on a stalk, while others look
like a piece of chewing gum stuck to the skin.
Treatment: If they become irritated or start to bleed, they should be
removed. In general, they are not a threat to the health of the cat.