Presentation
Left oculomotor nerve palsy.
Patient Data
Thickening of the left oculomotor nerve with a small well-defined mass (7 x 6 x 4 mm) involving its cisternal segment adjacent to the left cerebral peduncle. It shows an intermediate signal on both T1 and T2 with vivid homogeneous enhancement on postcontrast sequences.
The left oculomotor nerve shows normal thickness and signal intensity.
Normal size and configuration of the ventricular system with no other abnormality at the infra-or supratentorial level.
Annotated images showing the mass involving the cisternal segment of the left oculomotor nerve.
- PCA = posterior cerebral artery
- SCA = superior cerebellar artery
Case Discussion
MRI features of a focal homogeneously enhancing lesion of the cisternal segment of the left oculomotor nerve suggestive of a schwannoma.
Sporadic oculomotor schwannoma is very rarely seen 1. Multiple schwannomas are a characteristic of neurofibromatosis type 2 (NF2).