Primary intraocular primitive neuroectodermal tumor (retinoblastoma) causing unilateral blindness in a gelding.

This research article discusses a rare case of an adult horse developing a retinoblastoma causing blindness in one eye, and the subsequent treatments that enabled the horse to resume normal activities after a brief recovery period.

Background:

• The study focuses on a 14-year-old gray gelding, a domesticated male horse, that was examined due to the presence of a pale-colored ocular mass in its right eye.
• This horse’s condition drew interest because it presented an opportunity to explore the manifestation and treatment potential of intraocular primitive neuroectodermal tumors, specifically retinoblastomas and medulloepitheliomas, in equines.

Diagnosis:

• Clinical and ultrasonographic examinations revealed an intraocular mass stemming from the superior nasal quadrant of the ciliary body and the retina, both important components of the eye responsible for vision.
• The mass had proliferated significantly, taking over the majority of the vitreous chamber (the clear inner part of the eye behind the lens) and some of the superior anterior chamber (the fluid-filled compartment at the front part of the eye between the cornea and the iris).
• This eye condition had caused the horse to lose vision in the affected eye, thus confirming its blindness in the right eye.

Treatment and Outcome:

• Exenteration, a surgical procedure to remove the entire contents of the horse’s eye socket, was performed as part of the treatment approach.
• Pathological examination post-operatively identified the intraocular mass as a primary intraocular primitive neuroectodermal tumor, a rarely found ocular mass in adult horses.
• Following a short recovery period from the exenteration, the gelding was able to return to normal use, demonstrating the success and effectiveness of the treatment method employed in this unique case.