Cerebellopontine angle meningioma

Case contributed by Dr Bruno Di Muzio

Presentation

Left trigeminal neuralgia and sensorineural hearing loss.

Patient Data

Age: 45 years
Gender: Female
MRI

MRI Brain

Left cerebellopontine angle dural based solid mass extending into and mildly expanding the left internal acoustic canal has remained stable in appearances and dimensions compared to the recent images (not shown in this case). It shows to be isointense on T1 and slightly hyperintense on T2 compared to the cortex, having a vivid and homogeneous contrast enhancement. The lesion encases part of the left anterior inferior cerebellar artery (AICA), including its loop into the internal acoustic meatus. The most inferior aspect of the tumour projects onto the superior margin of the left jugular bulb without invasion, but does extend to the pars nervosa of the jugular foramen with likely encasement of lower cranial nerves. Mild compression of the pons and left middle cerebellar peduncle is noted. The left trigeminal nerve root entry zone and cisternal segment are compressed and mildly displaced by the tumour. Left Meckel's cave is asymmetrically very small in size. Although there is linear enhancement along its roof, it is not occupied or expanded by enhancing tumour. Contralateral internal acoustic meatus and contents appear unremarkable. Inner ear structures appear normal bilaterally. The remainder of the brain is unremarkable, with no intra-axial lesions. Ventricles have normal appearances.

Left maxillary sinus mucosal thickening again demonstrated.

CT

CT Temporal bones

The left internal acoustic canal measures 7.1 mm versus 4.9 mm on the right. No hyperostosis is demonstrated. The bony labyrinth and middle ear cleft appear normal. 

Case Discussion

This case demonstrates a left cerebellopontine mass that represents a meningioma. It shows extension into the left IAC, compression of the left trigeminal nerve and nerve root entry zone, and extends to pars nervosa of the left jugular foramen. AICA is encased by the tumour.

 

MACROSCOPIC DESCRIPTION: 1. "?Meningioma": A piece of firm tan tissue 20-3mm. All in for frozen section/smear. A1. FS DIAGNOSIS: Meningioma (TWR) 2. "Unlabelled as to site": Grey and brown tissue fragments 40mm in aggregate. A2. 

MICROSCOPIC DESCRIPTION: 1,2. 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 seen. No evidence of atypical or malignant change is identified.

DIAGNOSIS: 1,2. L post fossa tumour: Meningioma (WHO Grade I).

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Case information

rID: 48434
Case created: 7th Oct 2016
Last edited: 18th Jul 2017
Inclusion in quiz mode: Included

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