What Is a Sialocele (Salivary Mucocele)?

A dog with his tongue out
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A sialocele is a cyst filled with a collection of mucoid saliva in the tissues surrounding a salivary gland. These salivary gland cysts are known as sialocele (or a salivary mucocele). It is the most common salivary disorder in dogs and is noticed by a swelling under their neck or jaw. It can affect cats as well.

Dogs and cats have four salivary glands. The most commonly affected among them are the large ones under the jaw, called the mandibular salivary glands. The sublingual glands located under the tongue can also be affected.The cysts can become quite large and press against the animal's larynx or trachea, causing them to cough.

The exact cause of these cysts is often hard to determine. They may be induced by trauma to the gland or ducts or caused by an infection. It's also possible that they are the result of a growth that obstructs the ducts and causes a rupture. The saliva and mucus then escape into the surrounding tissues.

Are salivary gland cysts painful?

When these cysts first occur, your dog or cat may feel pain. However, most animals are presented with a large, non-painful, fluctuant mass under the jaw or tongue. These cysts can become infected which may cause pain and a generalized fever.

While not always painful, the large size of some masses may also functionally interfere with your pet's breathing or eating.

How is this condition diagnosed?

If you notice swelling below your pet's muzzle or neck, it is important to get them to a ​veterinarian for proper diagnosis and treatment. The cause may be sialocele or it may be something else, but in either case, they do need to be examined as soon as possible

When diagnosing sialocele, the vet will most likely use needle aspiration. During this procedure, a small needle is inserted into the lump and a sample of cells and liquids are removed. It is a very useful diagnostic tool for many veterinary situations, including salivary cysts. The characteristic aspirate for sialocele is a clear and sticky or stringy fluid (saliva) that may be tinged with a little blood.

It is important to look at the sample microscopically, too. This will help your vet rule out other diseases, such as cancer or infection. It also helps differentiate between problems with a salivary gland and another tissue that is in the area such as a swollen lymph node.

What if surgery is recommended?

Surgical removal of the damaged gland and duct is the treatment of choice. Some cases can be managed by installing drains and periodically emptying the cyst. Some cysts will resolve on their own, but infection, pain, and critical obstruction of the airways are potential risks if treatment is not utilized.

Since there are four different salivary glands in different locations, please discuss what would be the best individual treatment option for your pet with your veterinarian.


Reiter AM. Salivary Disorders in Small Animals: Salivary Mucocele. Merck Manual Veterinary Medicine. 2016