Cystic acoustic schwannoma

Case contributed by Dr Bruno Di Muzio

Presentation

Progressive sensorineural hearing loss on the right ear for the last year. No further clinical data was provided.

Patient Data

Age: 40-year-old
Gender: Male

MRI Brain

Modality: MRI

Technique: Multiplanar and multisequence images have been obtained through the brain, including dedicated thin slices for the posterior fossa and post contrast sequences. 

Findings: There is a solid-cystic mass on the right cerebellopontine angle extending into and enlarging the right IAC, and slightly compressing the adjacent pons and right middle cerebellar peduncle. The multiple cysts partially suppress on FLAIR and the solid components shows a homogeneous and vivid enhancement. 

On the sagittal T2 it is possible to spot a web obstruction the cerebral aqueduct. Asymmetric enlargement of the supratentorial ventricles with no signs of trans ependymal oedema. Colpocephaly on the right lateral ventricle. The corpus callosum is diffusely thin and displaced superiorly. 

The remainder brain is unremarkable.

Conclusion: Right cerebellopontine solid-cystic mass in keeping with a schwannoma. Chronic supratentorial obstructive hydrocephalus. Colpocephaly on the right lateral ventricle denotating loss of brain parenchyma (neonatal brain injury?). 

CT Temporal bones

Modality: CT

Technique: Dedicated fine cut scans through the temporal bones.

Findings: A hypodense mass measuring approximately 2.1 x 3.5 x 2.6 cm in the right cerebellopontine angle cistern with mass effect on the brainstem and cerebellar peduncle appears to extend into the right internal acoustic meatus with a mild remodelling of the porous acoustics (not shown above - refer to the MRI study).

The inferior portion of the fourth ventricle is effaced.

There is severe right and moderate left lateral ventricular dilation, with the defect in septum pellucidum. The third ventricle is mildly enlarged. On an external MRI, there is evidence of a web of the cerebral aqueduct. The corpus callosum is grossly thinned, with a relative deficiency of the splenium. Gross white matter volume loss on the right and fullness with stents in the left posterior cerebral hemisphere. Remodelling of the inner table of the skull is consistent with a chronic compensated hydrocephalus.

No acute intracranial haemorrhage.

Conclusion: Cystic right acoustic neuroma. Chronic hydrocephalus.

Case Discussion

The patient was submitted to a surgery for the tumour resection, pathology report as follow:

MICROSCOPIC DESCRIPTION: 1&2. Paraffin sections show fragments of a moderately hypercellular neurilemmoma (Schwannoma). This is composed of both Antoni A and B type tissues. Well formed Verocay bodies are noted in Antoni A areas. Tumour cells show mild nuclear pleomorphism. No mitotic figures, densely hypercellular areas or areas of necrosis are identified. Collections of both foamy and haemosiderin-filled macrophages are noted throughout the tumour.

DIAGNOSIS: 1&2. Vestibular tumour: Neurilemmoma (Schwannoma).

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Case Information

rID: 41178
Case created: 18th Nov 2015
Last edited: 20th Nov 2015
Tag: rmh
Inclusion in quiz mode: Included

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