Wk 4, Case 5 - Review

Patient History
Left hearing loss and vertigo.

Findings
Brain: Sagittal T1-weighted images demonstrate corpus callosum to be intact. No evidence of Chiari malformation. No abnormal pineal region masses. Mild flattening of pituitary gland. Diffusion imaging demonstrates no evidence of recent infarct. Axial FLAIR and T2-weighted images demonstrates prominence of sulci and ventricles. Multiple white matter hyperintensities involving the juxtacortical, centrum semiovale and periventricular white matter. No evidence of vasogenic edema or mass effect. No abnormal intraaxial enhancing masses.

Internal Auditory Canal: Pre- and postcontrast thin-section images performed through the internal auditory canal demonstrates a mass arising from the posterior aspect of the left petrous apex in the vicinity of the left endolymphatic duct. The mass is characterized by increased T1 signal and enhances with contrast. The heavily T2 weighted images demonstrate very heterogeneous appearance of the mass with internal cysts and septations. The superior aspect of the mass extends to the superior portion of the petrous apex. The inferior aspect of the extends into the left jugular foramen. However, the center of the mass appears to be centered along the posterior aspect of the petrous bone. There is no involvement of the petroclival fissure. The mass does have increased T1 signal on the noncontrast T1 weighted images, however, it is very heterogeneous T1 signal and is not well defined T1 signal.

Conclusions
1. Heterogeneous enhancing mass arising from the posterior aspect of the left petrous bone in the expected vicinity of the endolymphatic duct and highly suggestive of an endolymphatic sac tumor. Glomus jugulare tumors are typically centered at the jugular foramen where as this tumor is centered in the posterior petrous bone with secondary involvement of the jugular foramen. Cholesterol granulomas can have increased T1 signal, however, they are typically well-defined and arise from the petrous apex anterior to the internal auditory canal.
2. No abnormal intraaxial enhancing masses.
3. Prominence of sulci and ventricles with scattered white matter hyperintensities most likely due to microvascular angiopathy.