What to Know About Sialocele (Salivary Mucocele)

Diagnosis and treatment of Salivary Gland Cysts

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What Is Sialocele (aka Salivary Mucocele)?

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), and they can become quite large, sometimes inducing a cough (from pressing on the larynx or trachea). 

There are four salivary glands in the dog and cat. The most commonly affected glands are the large ones under the jaw, the mandibular salivary glands.

The sublingual (under the tongue) can also be affected.

The exact cause is often hard to determine, but causes include trauma to the gland or ducts, infection, or possibly a growth that obstructs the ducts, causing rupture. The saliva and mucus then escape into the surrounding tissues.

Are Salivary Gland Cysts a Painful Condition?

These cysts can be painful when they first occur, but most animals are presented with a large, non-painful, fluctuant mass under the jaw or under the tongue. These cysts can become infected, causing pain and generalized fever. Also, the large size of some masses, while not always painful, can sometimes functionally interfere with breathing or eating.

How Is This Condition Diagnosed?

Needle aspiration — taking a small needle, inserting it into the lump, and aspirating cells or liquids — is a very useful diagnostic tool for many situations, including salivary cyst. The characteristic aspirate is a clear, sticky or stringy fluid (saliva) that may be tinged with a little blood.

It is important to look at the sample microscopically too, to rule out other diseases, such as cancer or infection. It will also help differentiate between a salivary gland and other tissue, for example, a swollen lymph node (also in the area).

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 periodic emptying of 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.

1Merck Veterinary Manual, 8th edition, pg 702