Uh-oh. You've found a lump on Kitty. You'll have to take him to a vet for a definite diagnosis, but don't panic. It's likely just a cyst, not a tumor. It might be unsightly, but it's not life-threatening. After diagnosis, you and your vet can decide whether to remove it.
Cysts consist of sacs filled with fluid or solids -- they form the lump you found on Kitty's skin. These sacs have a lining which secretes the filling found inside the cysts. Over time, they might decrease or increase in size; they may disappear slowly on their own. Usually, surgical removal takes care of the problem, although occasionally a cyst returns. Cysts aren't contagious, so Kitty can't spread them to other pets. Different types of cysts contain different fillings and appear on various parts of the body.
If you find a lump or bump on Kitty that lingers, take him to the vet for an examination. If you're lucky, it is a cyst that your vet will either remove relatively easily or advise you to leave alone. The possibility exists that the lump is a tumor, either benign or malignant, or an abscess. You can't tell what it is simply by feeling the lump. The vet draws makes a diagnosis by inserting a fine needle into the lump and withdrawing fluid. Microscopic examination of the cells from this fluid can confirm whether it's a cyst.
The most common type of feline cyst, a sebaceous cyst forms because of an obstruction in a cat's hair follicles. Sebaceous cysts are also known as epidermoid or follicular cysts. Sebum, created by the cat's sebaceous glands on his skin, acts as a lubricant. If there's a blockage in the hair follicles, this substance accumulates, resulting in a cyst. Any cat can develop sebaceous cysts anywhere on the body. Varying in size, these cysts may appear bluish-gray. Inside, they're full of cheesy white-gray matter. Since it's not harming the cat, you don't have to take off a sebaceous cyst.
Also known as sweat gland cysts, apocrine cysts aren't that common in cats, and they tend to disappear quickly. These cysts fill with water that often eventually seeps out. Your vet might recommend leaving these alone as they'll probably disappear on their own. If the vet drains the cyst rather than removes it surgically, it's likely to fill back up.
Dilated Pores of Winer
If your old cat looks like he's growing a horn in the middle of his head, he could have a rare cyst called a "dilated pore of Winer." He may look like he's developing a giant zit on his noggin; it may have keratin poking out of it. This cyst doesn't hurt him ... but if you don't like the look of a cat with a bizarre growth on his head, your vet can cut it out.
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