Cholesterol granulomas in CNS in a cat

12-year-old male cat, suffering neurological symptoms, such as circling and left head tilt, with sudden blindness and behaviour changes. A head CT scan was performed.


Intracranially, there are 2 extra-axial lesions (red arrows) that seem to originate from both lateral ventricles, extending caudally, dorsal to the mesencephalon. Both lesions have well-defined and irregular margins, are hyperattenuating (140 HU), with mineralized material inside (420 HU), showing a moderate post-contrast enhancement.


cat ct brain mineralized material


These lesions cause a marked mass effect, displacing and compressing the diencephalon and mesencephalon ventrally (blue and green arrows respectively).

cat ct compression of mesencephalon.
cat ct compression of mesencephalon.

There is a marked, bilateral and symmetrical, distention of both lateral ventricles (yellow arrows). There is also a mild / moderate cerebellar herniation, with cerebellar extension through the foramen magnum (red arrows).

cat ct distention lateral ventricles.


  • Mineralized extra-axial lesions in both lateral ventricles, consistent with cholesterol granulomas, most likely, considering their characteristics. Other differentials, such as a neoplastic disease (e.g. choroid plexus tumour) are less likely, although cannot be ruled out.
  • Associated obstructive hydrocephalus and mild cerebellar herniation.

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