Presentation
Hearing loss on the right.
Patient Data
Within the right cerebellopontine angle, there is a lobulated mass which is of intermediate to high T2 signal, demonstrates vivid but somewhat heterogeneous contrast enhancement and facilitated diffusion. It is clearly extra-axial and centered on the internal acoustic meatus with however only minimal extension within. There is no convincing attachment to the dura. The middle cerebral peduncle is significantly distorted, and the trigeminal nerve is displaced above the mass.
Conclusion: Large right cerebellopontine angle mass presumably represents an acoustic schwannoma.
Case Discussion
The patient went on to have a resection.
Histology
MICROSCOPIC DESCRIPTION: The sections show a moderately cellular schwannoma. It mainly contains Antoni A areas with fascicles of spindle cells. There is focal palisading but Verocay body formation is inconspicuous. A small amount of Antoni B areas with microcystic change is also seen. The tumor cells show no significant nuclear pleomorphism. Mitoses are inconspicuous. No evidence of malignancy is identified.
FINAL DIAGNOSIS: Schwannoma.