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Histiocytomas in Dogs

There are many different types of skin masses on dogs. It can be scary when you find one; however, some are benign or non-cancerous. Histiocytomas are a type of benign skin mass or “tumor,” meaning they are non-cancerous or not malignant. Read on to learn more about what causes them, what they look like, and how they’re treated.

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Causes of Histiocytomas in Dogs

Histiocytomas are a common skin tumor usually seen in dogs under 2 years of age. They grow out of an immune cell called a “histiocyte” which is there to protect against anything harmful in the environment. Histiocytes are present wherever there is contact with the environment, such as the stomach, intestines, nose, and especially in the skin.

The cause of histiocytomas is unknown at this point. However, there may be a genetic connection as they seem to occur more frequently in certain breeds such as Cocker Spaniels, Great Danes, Shelties, Dachshunds, Boxers, Bull Terriers, and certain types of Retrievers (specifically, Flat-Coated).

What do histiocytomas look like?

Histiocytomas usually appear in dogs under the age of 2 and are a fast-growing mass or tumor. They are usually raised, firm, non-painful and are most likely to be a solitary mass. They can also have the appearance of a button and may be referred to as a “button tumor.”

The most common places they’re found are on the legs, head/neck area, and occasionally on the ear.

How are histiocytomas diagnosed in dogs?

Histiocytomas are often diagnosed simply on their appearance alone, given the dog is still fairly young at the time of appearance. When in doubt, vets may perform a simple procedure called a “fine needle aspirate”. This test involves inserting a tiny needle into the mass. Some of the cells are withdrawn, and either examined under a microscope in the office or sent out to a lab to be evaluated by a pathologist.

Treatment of Histiocytomas in Dogs

The treatment of histiocytomas usually begins by simply monitoring the mass for changes in things such as size, color, texture, and discomfort. Most histiocytomas recede or just go away on their own in a few months and rarely if ever, return. If there’s any concern, however, they can simply be surgically removed.

If you find a skin mass on your puppy or dog, it’s best not to panic. Always contact a vet.

Read more:

Lumps and Bumps on Dogs and Cats

Mast Cell Tumors in Dogs

Warning Signs of Cancer in Dogs

Have more questions about histiocytomas in dogs?

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