Attempted ablation of an orbital cyst in a dog with 1% polidocanol using fluoroscopy and contrast cystography

A 4-year-old female spayed mixed-breed dog received enucleation surgery of the right eye in 2018 following the diagnosis of glaucoma. The patient was presented in 2021 for recurrent swelling of the right orbit. Ultrasound confirmed the presence of a cystic structure, and chemical ablation with 1% polidocanol (compounded, Stokes Pharmacy, Mt. Laurel, NJ) and contrast cystography was elected for treatment. Iodinated contrast was injected under fluoroscopy and after no leakage was noted, the contrast was aspirated from the orbital cyst and immediately followed by an injection of 1% polidocanol solution. The orbital cyst collapsed within 24 h but returned 25 days post-injection. A second attempt was made for chemical cyst wall ablation with 1% polidocanol foam and ultrasound guidance. The orbital cyst returned 12 weeks post 1% polidocanol foam injection, and the patient presented for surgical removal. Histopathology revealed an orbital conjunctival inclusion cyst associated with granulomatous and lymphoplasmacytic inflammation. Histopathology confirmed that the draining cyst was lined by conjunctiva and likely represented conjunctival remnants from the previous enucleation. This report describes fluoroscopic guidance for sclerotherapy in the treatment of a post-enucleation orbital cyst in a dog. Contrast cystography may be useful to verify catheter position and demonstrate cyst margins prior to injection. This case report highlights the importance of complete conjunctival excision during enucleation.