Article
Unilateral cerebellar hypoplasia and mesencephalic malformation in a Hanoverianthoroughbred foal
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Published: | September 11, 2012 |
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Unilateral absence of a cerebellar hemisphere and vermis accompanied by contralateral malformation of the mesencephalon was diagnosed in a Hanoverian foal. The missing areas of the right cerebellar hemisphere were replaced by a cystic formation. The left part of the mesencephalic lamina quadrigemina was reduced in size and the corpus callosum was hypoplastic. Additional microscopical findings were most obvious near the cyst formation and include angiofibrosis in remaining cerebellar and mesencephalic parenchyma and leptomeninges, heterotopia of cerebellar neurons, sclerosis in cerebellar cortex, focal proliferation of meningeal cells and mild mononuclear perivascular infiltrates. Occassional irregular neuronal arrangement in the mesencephalon was also present. Infectious agents such as Borna disease virus, rabies virus, and equine herpesvirus were not detected. Therefore, the complex malformation in this foal might have been caused by a destructive, possibly ischemic event, or could represent a sequel of a primary retrocerebellar cyst with accompanying compression of adjacent parenchyma.