34 year-old with dizzy spells and frequent headaches

This is unpublished
CT axial bone windows.
CT axial bone windows
CT axial bone windows.
CT axial bone windows
CT axial postcontrast soft tissue windows.
CT axial postcontrast soft tissue windows
Axial noncontrast T1.
Axial noncontrast T1
Axial noncontrast T2.
Axial noncontrast T2
Axial FLAIR.
Axial FLAIR
Coronal T2 fat sat.
Coronal T2 fat sat

Findings:

CT: Lytic relatively well circumscribed lesion in the petro-clival junction region
MR: High T2 and FLAIR and intermediate T1 signal intensity somewhat heterogeneous

DDX:

Chordoma, chondrosarcoma, metastasis, atypical cholesterol granuloma

Diagnosis:

Cholesterol granuloma

Discussion:

The well circumscribed border favors a benign lesion although this case is atypical on MR since these lesions usually show high T1 signal. The pathogenesis is usually related attributed to eustachian tube dysfunction, leading to mucosal edema and chronic hemorrhage. The encapsulated blood products undergo degeneration and provoke a chronic inflammatory response.

Submitted by John Rhee, MD, UW Neuroradiology Fellow