Cerebral abscess

Case contributed by Dr Abdallah Khateeb

Presentation

The patient presented acutely with high fever, headache and retractable seizures. He had a previous history of acute bacterial endocarditis.

Patient Data

Age: 45
Gender: Male
MRI

There is a space-occupying lesion situated at the right parietal lobe. It has an irregular border that is low signal on T2 images. The center of the lesion is intermediate on T1 and hyperintense on T2 images.  The lesion is surrounded by voluminous vasogenic edema that distorts and expands the lobe and results in brain structures shift into the contralateral side. On the ADC map, the lesion shows diffusion restriction due to a center of viscous pus. On the post-contrast images, the lesion shows wall enhancement  in the so called ring pattern.

Changes of sinusitis are also seen in the left maxillary sinus.

Case Discussion

This case illustrates the typical clinical presentation of brain abscess and the MRI findings.

"The appearance of a brain abscess as a rim-enhancing mass is non-specific and may be mimicked by metastasis, glioblastoma and resolving haematoma. A thick, irregular rind of enhancement is more suggestive of tumour. Abscesses are more likely to show small satellite lesions. Despite initial hopes that restricted diffusion would reliably distinguish abscess from tumour, reduced ADC has been subsequently reported in metastases and
glioblastomas."

Remember that a cystic lesion that markedly restricts centrally (the fluid component) on DWI should be considered an abscess until proven otherwise. Upon surgical intervention, brain abscess was confirmed.

Please note that the usual and the more common pattern of enhancement found in brain abscesses is that of a smooth thin rim rather than a lobulated border as in this patient.

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Case information

rID: 39688
Case created: 15th Sep 2015
Last edited: 21st Dec 2016
Inclusion in quiz mode: Included

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