Today’s case is a 17-year-old female neutered Yorkshire Terrier with history of a seizure-like episode.
How would you characterize this lesion in the cerebellum?
A intra-axial mass
B extra-axial mass
D inflammatory disease
Standard sequences and views were obtained with the addition of a dorsal FLAIR sequence. There is a large, well-defined region which is hypointense on T1 and hyperintense on T2 extending into the left cerebellar hemisphere from the dorsal margin. The lesion extends nearly the entire breadth of the left hemisphere. There is a region of mild T2 hyperintensity adjacent to the lesion on the lateral margin of the cerebellum. There is a similar, smaller lesion on the lateral margin of the right cerebellar hemisphere, again with associated T2 and FLAIR hyperintensity extending from it. There is symmetrical T2 hyperintensity extending through the white matter tracts of the cerebrum. The ventricular system is diffusely, symmetrically dilated; no obstructive lesions are identified. The sulci and gyri are prominent. A small, rounded, T2 hyperintensity is present at the ventrolateral margin of the right osseous bulla which is otherwise within normal limits. A small amount of liquid is present in the dorsal aspect of the left nasal passage. There is right sided temporalis muscle atrophy.
Axial and dorsal T1 weighted sequences were performed after contrast administration. No contrast enhancement is identified in the brain. There is a small round enhancing structure within the longus capitus muscle.
Imaging findings are most consistent with multifocal cerebellar infarction. Cortical atrophy with ventriculomegaly. White matter hyperintensity is a common finding in aged dogs and may represent a degenerative change. Fluid pocket adjacent to the right osseous bulla of unknown clinical significance. Mild right temporalis muscle atrophy and mild rhinitis. Possible infarct in the longus capitis muscle.