Imaging diagnosis-paraganglioma of the cauda equina: MR findings.

The magnetic resonance imaging features of a cauda equina paraganglioma in a 5-year-old dog are described. Imaging revealed a well-defined, strongly contrast-enhancing mass invading the adjacent vertebral body and infiltrating the intervertebral foramen bilaterally. Flow void, compatible with increased drainage veins around the mass, and macroscopically visible neovessels in contrast-enhanced magnetic resonance angiography, as reported in numerous human studies, were not visible in this single case. The tumor recurred despite aggressive surgery and radiotherapy. This neoplasm should be considered in the differential diagnosis of cauda equina abnormalities in dogs.