Salivary mucoceles are formed by the extravasation and accumulation of saliva in tissues adjacent to a salivary gland. The accumulated saliva incites an inflammatory response, leading to a walled-off accumulation of mucoid fluid. Trauma can cause salivary mucoceles; however, most cases are idiopathic.1
Salivary mucoceles are uncommon in cats. Although individual case reports of feline salivary mucoceles exist,2-8 no case series has been reported in the veterinary literature.
In this article, we present findings from our review of the records of seven cats with salivary mucoceles to help identify common presenting signs and the best form of treatment.
SALIVARY MUCOCELES: AN OVERVIEW
In cats, salivary mucoceles range from nonclinical to life-threatening in severity.2-8 Cats have five major salivary glands (parotid, mandibular, sublingual, molar, zygomatic) compared with dogs' four (parotid, mandibular, sublingual, zygomatic),9,10,11 and mucoceles in cats have been associated with all but the molar gland.2-8 In dogs, the most commonly affected gland is the sublingual gland.12 However, the small number of cases in cats makes determining the most commonly affected salivary gland difficult.
Clinical signs and diagnosis
Clinical signs of mucoceles include a fluctuant, nonpainful mass close to the salivary glands, dysphagia, exophthalmia, and dyspnea. Signs largely depend on the location and size of the mucocele. Differential diagnoses include an abscess, neoplasia, a foreign body, and a granuloma.
Diagnosis involves aspiration of a thick, stringy, golden fluid with low cellularity from the mass.1,13 Sialography has been performed in dogs and may be useful for identifying specific gland involvement when it is not readily apparent.12,13 Other diagnostic imaging tests (radiography, ultrasonography, computed tomography) may help rule out other disease processes, such as a foreign object or involvement or invasion of multiple tissues, but are unlikely to definitively identify a salivary mucocele.14,15
Treatment options include draining the mucocele, marsupialization, and removing the involved gland. Drainage alone is likely to result in recurrence unless the mucus source is addressed. Marsupialization, which involves excising an elliptical section of mucosa over the mucocele, draining the saliva, and apposing the mucosal surface to underlying connective tissue, does not address the underlying problem. And because of potential complications such as frequent recurrence and the fact that future surgical intervention would be difficult, it is not the preferred procedure.1,13,16 Thus, surgically excising the affected gland is ideal.
CRITERIA FOR CASE SELECTION
The medical records of all cats examined for further management of a salivary mucocele at the University of Pennsylvania Matthew J. Ryan Veterinary Hospital and Red Bank Veterinary Hospital between 1993 and 2006 were reviewed. Cats with confirmed salivary mucoceles that were surgically repaired were included in this case series. Seven cats met these criteria.
PROCEDURES AND RESULTS
Each cat's history; signalment; physical examination, complete blood count (cbc), and serum chemistry profile results (when available); clinical signs; treatment; and outcome were identified and recorded. The signalment and location and surgical correction of the mucoceles for the seven cats are shown in Table 1.
Table 1: Medical Records of Seven Cats with Surgically Treated Salivary Mucoceles (1993-2006)