A salivary mucocele (or sialocele) occurs when a salivary gland or duct becomes damaged or blocked, causing mucoid saliva to leak into the surrounding tissue. This is the most common salivary gland disorder of dogs. While any of the salivary glands may be affected, the sublingual (under the tongue) and mandibular salivary glands are most commonly affected. Usually the saliva collects in the area of the jaw or neck, but it may also collect in the tissue under the tongue. The cause may be traumatic or inflammatory blockage or rupture of the duct of the sublingual, mandibular, parotid, or zygomatic salivary gland. Usually, the cause is not determined, but a developmental predisposition in dogs has been suggested.
Signs depend on the site of saliva accumulation. In the acute phase of saliva accumulation, the inflammatory response results in the area being swollen and painful. Frequently this stage goes unnoticed, and the first obeserved sign may be a nonpainful, slowly enlarging, fluctuant mass, frequently in the cervical region. A salivary mucocele in the mouth may not be seen until it is traumatized and bleeds. A pharyngeal mucocele may obstruct the airways and result in moderate to severe respiratory distress.
- Oral Mass Growth
- Skin Lump
A mucocele is detectable as a soft, fluctuant, painless mass that must be differentiated from abscesses, tumors, and other cystsof the neck. Pain or fever may be present if the mucocele becomes infected. A salivary mucocele usually can be diagnosed by palpation and aspiration of the characteristic golden or blood-tinged, stringy saliva. Usually, careful palpation with the animal on its back can determine the affected side; if not, sialography may be helpful. Sialography is the radiographic evaluation of the salivary glands after contrast media has been injected into a salivary gland in order to better visualize the salivary glands and ducts.
Surgery is recommended to remove the damaged salivary gland and duct in most cases. Cervical mucoceles can be managed with periodic drainage if surgery is not an option. For mucoceles that are located under the tongue, drainage or gland removal has been recommended. Complete gland and duct removal is recommended for pharyngeal mucoceles to avoid future life-threatening airway obstruction.