Choroid plexus cyst, corticocerebral necrosis and hydrosyringomyelia in a dog

A twenty-month-old Springer Spaniel presented with a history of episodic left head tilt appeared after physical effort six months before. The dog received oral prednisolone 0.8 mg/kg SID with slight improvement. After the neurological examination a cervical spinal cord/posterior fossa localization was suspected. When the prednisolone treatment was tapered off the neurological status deteriorated and was consistent with a diffuse cerebral localization. The magnetic resonance imaging of the brain revealed a well-defined mass (cm 1,7x1,2x2,3) within the fourth ventricle, hyperintense on T2-weighted images (T2WI) and hypointense on pre and post contrast T1-weighted images (T1WI); in T2WI a severe, diffuse, poor defined cortical hyperintensity in both cerebral hemispheres and in the dorsocaudal part of the cerebellar vermis. These areas were mildly hypointense in T1WI and enhanced diffusely on post-contrast T1WI. T2WI of the cervical spine showed a severe hydrosyringomyelia and a diffuse hyperintensity of the spinal cord. Histophatological investigation confirmed a widespread bilateral and symmetrical necrosis of cortical grey matter, a focal cystic lesion in the fourth ventricle consistent with a choroid plexus cyst (CPC), and a marked dilation of the central canal of the cervical spinal cord with two adjacent syrinx (hydrosyringomyelia). To our knowledge this is the first case reporting in the same patient two rare conditions as diffuse cerebrocortical necrosis and CPC. We suspected a peracute worsening of a chronic impairment in cerebrospinal fluid flow at the foramen magnum, due to the CPC, and a sudden increase of the intracranial pressure causing a diffuse ischaemic lesion of the cerebral cortex.