Case 035

History/Physical

History/Physical:

50-year-old right-handed male.

Progressive ataxia over the past year.

Trilobed well-defined mass with avid enhancement. This is extra-axial, dorsal to the vermis.

The superior surface of the lesion abuts the tentorium (arrows).

Without contrast, the mass is difficult to perceive.

Diagnosis: Solitary fibrous tumour

Highly vascular tumour with complex branched lumens.

Mitotically active tumour with cells having spindle to oval nuclei and moderate volumes of pale cytoplasm.

Extensive CD34 expression among tumour cells.

Extensive light vimentin expression.

There is a dense network of reticulin (black) with investment of individual tumour cells.
Additional studies confirmed nuclear STAT6 expression (not shown).