Ganglioglioma of the Right Cerebrothalamus in a 7-Year-Old Quarter Horse Cross Gelding.

The research article describes a case of a rare brain tumor, called ganglioglioma, found in a 7-year-old Quarter horse cross Paint gelding. The horse exhibited seizure-like symptoms and neurological abnormalities that led to diagnosis and the decision to perform an electroencephalogram and immunohistochemical examination. This study adds ganglioglioma to the list of potential causes of brain masses and seizures in horses.

Case Presentation

• The Quarter horse cross Paint gelding was brought in for examination due to recurrent, and increasingly frequent and long, seizure-like episodes. At the time of the examination, these episodes were occurring up to 20 times a day.
• During a neurological examination, the horse exhibited a variety of symptoms including intermittent confusion, many left-sided abnormalities such as facial and tongue paralysis, facial hypersensitivity and neck numbness, coordination issues, extra movement in the front limbs when the head was lifted, and seizure-like activity. However, the horse’s cranial nerve reflexes were normal.
• The horse also exhibited vocalization, rapid eye movement, intermittent blindness, a left-side head tilt and neck flexion, and lack of response to environmental stimuli during seizure activity.
• Given these symptoms, a right sided cerebrothalamic disease was suspected.

Diagnostic Tests and Results

• An electroencephalogram was performed which confirmed the presence of seizure activity, mainly focused on the right side in the central, parietal, and occipital regions of the brain. This result further supported the suspicion of a disease localized in the cerebrothalamus.
• Additionally, the electroencephalogram showed subclinical paroxysmal activity, which are irregular brain waves often associated with seizures.
• Immunohistochemical examination, a method used to visually detect specific antigens in cells of a tissue section, revealed the presence of a ganglioglioma in the right cerebrothalamic area as well as in other parts of the brainstem.

Implications of the Findings

• This case and the subsequent diagnose represent the first documented occurrence of a ganglioglioma, a typically benign and slow-growing tumor, in a horse. Up until this point, gangliogliomas had not been reported in horses.
• The research led the authors to suggest that this type of intracranial neoplasia should be included as a possible cause of brain masses and seizures in horses, thus broadening the spectrum of possible diagnoses in such cases.