Post-retinal blindness as the sole clinical sign of intracranial neoplasia in two dogs

Authors: Richardson SR
Publication: Australian Veterinary Practitioner, Volume 51, Issue 3, pp 174-181, Sep 2021
Publisher: Australian Veterinary Association

Subject Terms: Clinical examination, Eye/opthalmology, Neoplasia
Article class: Clinical Report

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Abstract:

A 12-year-old female spayed Shih Tzu-cross (Case 1) and a 12-year-old female spayed Welsh Pembroke corgi (Case 2) presented for acute blindness to a veterinary referral hospital. The blindness in each case was characterised by mydriasis and an abnormal pupillary light reflex (PLR). The electroretinogram waveform was normal in each case. Magnetic resonance imaging revealed a contrast-enhancing mass at the level of the pituitary fossa and optic chiasm in Case 1, and a contrast-enhancing mass at the base of the cranial vault at the level of the pituitary invading both optic tracts in Case 2. Both cases were presumptively diagnosed with meningioma. Both cases underwent radiation therapy (RT) with a total radiation dose of 45 Gy delivered in 18 daily fractions of 2.5 Gy. During RT, both cases regained vision: Case 1 bilaterally and Case 2 in the left eye only. Case 1 remained sighted for 24 months after completion of RT and was euthanised at 25 months. Case 2 remained sighted for at least 15 months and died 16 months after completion of RT.

Blindness with mydriasis and PLR deficits is an uncommon presenting sign of intracranial neoplasia which has been infrequently reported. To the author’s knowledge, there are no previous reports of successful treatment outcomes for such cases.

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