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Sublingual sialocoele in a dog[1]

Sialocoeles (salivary mucocoeles) are a swelling of the canine salivary glands, usually involving the pharyngeal, zygomatic[2], mandibular, palatine[3] and sublingual salivary glands.

Ranulas involve mucocoeles associated with oral mucosa and are usually self-limiting.

This condition can be caused by salivary calculi, pharyngeal pouch and cleft remnants[4], foreign bodies, parasites (e.g. aberrant migration of Dirofilaria immitis[5]) and infections, often resulting in secondary sialadenitis.

Idiopathic sialocoeles are common and this condition has also been reported following maxillary tooth extraction, caudal hemimaxillectomy[6], parotid duct transposition[7] and in association with gangliosidosis.

Sialocoeles may result in salivary gland necrosis[8].

Trauma or chronic inflammation associated with the salivary gland can lead to metaplastic ossification, making surgical intervention difficult[9].

Clinical signs include swelling of the cheek and pain on opening of the mouth and an obvious swelling over the affected gland.

Exopthalmos is commonly reported with parotid gland involvement, leading to dorsolateral deviation of the globe and protrusion of the third eyelid.

Diagnosis is usually based on aspiration cytology, which usually reveals a mucoid substance. Culture and microscopic examination of cell content is required to exclude other causes[10].

A differential diagnosis would include squamous cell carcinoma, salivary gland adenoma[11], salivary gland adenocarcinoma and necrotizing sialometaplasia.

Treatment usually involves paracentesis or surgical lancing of the swollen glands and placement of drainage tubes. Sialoadenectomy (removal of the gland) may be required in large, recurrent lesions[12].

Sclerosing agents have been used to inject into the salivary gland (e.g.1% polidocanol).

Broad-spectrum antimicrobials are recommended.


  1. Veterinary Image Bank
  2. Adams P et al (2011) Zygomatic salivary mucocoele in a Lhasa apso following maxillary tooth extraction. Vet Rec 168(17):458
  3. Watanabe K et al (2012) First case of salivary mucocele originating from the minor salivary gland of the soft palate in a dog. J Vet Med Sci 74(1):71-74
  4. Nelson LL et al (2012) Pharyngeal pouch and cleft remnants in the dog and cat: a case series and review. J Am Anim Hosp Assoc 48(2):105-112
  5. Henry CJ (1992) Salivary mucocele associated with dirofilariasis in a dog. J Am Vet Med Assoc 200(12):1965-1966
  6. Clarke BS & L'Eplattenier HF (2010) Zygomatic salivary mucocoele as a postoperative complication following caudal hemimaxillectomy in a dog. J Small Anim Pract 51(9):495-498
  7. Termote S et al (2003) Parotid salivary duct mucocoele and sialolithiasis following parotid duct transposition. J Small Anim Pract 44(1):21-23
  8. McGill S et al (2009) Concurrent sialocoele and necrotising sialadenitis in a dog. J Small Anim Pract 50(3):151-156
  9. Prassinos NN et al (2005) Metaplastic ossification of a cervical sialocoele in a dog. Aust Vet J 83(7):421-423
  10. Benjamino KP et al (2012) Pharyngeal mucoceles in dogs: 14 cases. J Am Anim Hosp Assoc 48(1):31-35
  11. Shimoyama Y et al (2006) Pleomorphic adenoma of the salivary gland in two dogs. J Comp Pathol 134(2-3):254-259
  12. Ritter MJ et al (2006) Mandibular and sublingual sialocoeles in the dog: a retrospective evaluation of 41 cases, using the ventral approach for treatment. N Z Vet J 54(6):333-337