Wk 3, Case 1 - Review

Patient History
Right hypoglossal nerve dysfunction.

Findings
Pre- and postcontrast MR was performed of the brain with thin section images through the skull base.

Brain: Noncontrast sagittal T1 weighted images show no evidence of Chiari malformation. The corpus callosum is intact. No abnormal pineal region masses are seen. The pituitary gland is not enlarged. Diffusion imaging shows no evidence of recent infarct. The axial FLAIR and T2 weighted images show prominence of the sulci and ventricles. There is no evidence of vasogenic edema or mass effect. The contrast-enhanced T1 weighted images show no abnormal intra-axial or extra-axial enhancing lesions. The inferior portion of the brain MRI extended to the superior aspect of the right oral tongue. There is a subtle suggestion of potentially some fatty infiltration involving the intrinsic muscle of the right half of the mobile tongue.

Skull Base: Thin-section imaging performed through the skull base shows an enhancing lesion that measures approximately 9mm x 7mm located in the right hypoglossal canal and is best seen on image 7 of series 15 and images 5 and 6 of series 16. These findings are most consistent with a right hypoglossal nerve schwannoma. The contrast-enhanced T1 weighted images show no abnormal enhancing lesions in either internal auditory canal. No abnormal enhancement is seen in either cochlear or vestibule. No evidence of pericochlear enhancement is seen. There is no evidence of focal increased T1 signal involving either cochlear or vestibule to suggest spontaneous labyrinthine hemorrhage.

Conclusions
1. Enhancing mass in the right hypoglossal foramen which is suggestive of a right hypoglossal nerve schwannoma.
2. No abnormal enhancing masses in either internal auditory canal.
3. Prominence of the sulci and ventricles without evidence of vasogenic edema.
4. No abnormal intra-axial enhancing lesions in the brain.