Different outcomes of multiple sialadenitis involving the submandibular and zygomatic salivary glands in a Welsh Corgi dog

A ten-year-old indoor, castrated male Cardigan Welsh Corgi (Canis familiaris) presented with the chief complaints of chronic vomiting, retching, hypersalivation, and bilateral submandibular masses for two months. The systemic examinations, including serum chemistry, radiography, ultrasonography, and fluoroscopy, were unremarkable. A fine-needle aspiration revealed bilateral submandibular sialadenitis. Broad-spectrum antibiotics with phenobarbital were prescribed to alleviate the ptyalism. Thereafter, the left submandibular glands were normalised, and the right submandibular glands decreased to half their size. Three weeks later, the animal had an emergency visit because of a sudden left exophthalmos. Computed tomography and magnetic resonance imaging revealed enlarged left zygomatic and right mandibular salivary glands. The affected glands were surgically removed; the histopathologic examination confirmed non-septic sialadenitis, and the patient was finally diagnosed with idiopathic sialadenitis. Vomiting continued after the gland removal and the dog required a gradual increase in the phenobarbital dosage and an additional antiepileptic drug (potassium bromide) to manage the symptoms. The patient died eight months later from an unknown cause. This case report of bilateral submandibular sialadenitis concurrent with unilateral zygomatic sialadenitis in a Welsh Corgi dog suggests that when multiple salivary glands are involved, the response to anti-epileptic drugs and the prognosis is poor compared to that involving a single salivary gland.