# Magnetic Resonance Imaging Findings in a Case of Presumed Unilateral Trigeminal Ganglion Aplasia in a 3‐Year‐Old Female French Bulldog

## TL;DR

A young French bulldog with chronic dry eye and sudden paralysis was found to have an extremely rare condition involving the absence of a facial nerve structure.

## Contribution

This case report highlights trigeminal ganglion aplasia as a rare differential diagnosis in young dogs with non-responsive dry eye and corneal issues.

## Key findings

- MRI revealed severe hypoplasia or absence of the right trigeminal ganglion in the dog.
- The condition is consistent with congenital trigeminal hypoplasia/aplasia reported in humans.
- The case emphasizes the importance of considering this rare differential in dogs with non-responsive keratoconjunctivitis sicca.

## Abstract

A young female French bulldog with a history of chronic right keratoconjunctivitis sicca (KCS) because since birth was referred for an acute onset of nonambulatory tetraparesis. Right trigeminal nerve sensory deficits, including right corneal anesthesia and absent facial sensation, were identified during examination. Magnetic resonance imaging (MRI) of the neurocranium was performed, revealing severe hypoplasia to the absence of the right trigeminal ganglion, consistent with reports of congenital trigeminal hypoplasia/aplasia in human medicine. This represents a very rare but important differential in young patients with a history of non‐responsive KCS, recurrent or slow healing corneal ulceration, and absent corneal sensation.