The differential diagnosis of cerebellopontine angle masses include vestibular schwannoma (most common), meningioma, and epidermoid cyst. This patient had the mass excised.
Microscopic description: The sections show a moderately cellular meningioma. The tumour forms whorls. No sheeting arrangement is seen. The tumour cells have ovoid nuclei with no nuclear pleomorphism. Mitoses are inconspicuous. There is no necrosis. No brain parenchyma is present. No evidence of atypical or malignant change is identified.
Final diagnosis: Left cerebellopontine angle tumour: meningioma (WHO grade I).
This is centred is centred posteriorly to the internal acoustic meatus, and has imaging characteristics that are characteristic of a meningioma.