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, foreign bodies, parasites (e.g. aberrant migration of Dirofilaria immitis) and infections, often resulting in secondary sialadenitis.
Idiopathic sialocoeles are common and this condition has also been reported following maxillary tooth extraction, caudal hemimaxillectomy, parotid duct transposition and in association with gangliosidosis.
Trauma or chronic inflammation associated with the salivary gland can lead to metaplastic ossification, making surgical intervention difficult.
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.
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.
Sclerosing agents have been used to inject into the salivary gland (e.g.1% polidocanol).
Broad-spectrum antimicrobials are recommended.
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