Dacryoendoscopy for dacryocystitis management in a dog: A case report.

A castrated, mixed-breed, 10-year-old male dog developed a skin fistula from a ruptured periorbital swelling on the right eye; the patient was successfully treated with dacryoendoscope-guided cannulation using a nasolacrimal tube. On presentation, computed tomography with concurrent dacryocystography (CT-DCG) revealed obstruction of the right nasolacrimal duct and abnormal flow of contrast agents towards the root of tooth 109 at the right maxillary bone; however, the origin of the fistula remained unclear on CT-DCG. Dacryoendoscopy was used to confirm the physical association between the fistula and the nasolacrimal duct; the fistula end was found to be near the right upper gum mucosa around tooth 107. CT-DCG and dacryoendoscopy revealed that the periorbital swelling occurred owing to an infection or inflammation of the accessory nasolacrimal duct. The fistula end was connected to the oral cavity through a nasolacrimal tube installed in the oral mucosa. The tube was removed a week later, and the clinical symptoms completely resolved.