Cerebral abscess

Case contributed by A.Prof Frank Gaillard

Presentation

Acute onset of seizures. Recently unwell.

Patient Data

Age: 30 years
Gender: Male
CT

Centred on the grey-white matter junction of the right frontal lobe is a ring enhancing lesion (which is slightly hyperdense pre-contrast) surrounded by low density white matter change, consistent with vasogenic oedema.  This has moderate local mass effect. 

Low density in the left occipital region with volume loss is consistent with an old area of gliosis. No other abnormality. 

CT

Centred on the grey-white matter junction of the right frontal lobe is a ring enhancing lesion (which is slightly hyperdense pre-contrast) surrounded by low density white matter change, consistent with vasogenic oedema.  This has moderate local mass effect. 

Low density in the left occipital region with volume loss is consistent with an old area of gliosis. No other abnormality. 

MRI

Lobulated mass measuring 22 x 17 x 17 mm centred on the grey-white matter junction in the right posteroinferior frontal lobe demonstrates isointense FLAIR signal, hyperintense central T2 signal with a rim which is T2 hypointense, and slightly T1 hyperintense signal with thick peripheral contrast enhancement.  The lesion involves the cortex and appears to have ruptured through the cortex with adjacent meningeal enhancement. It is surrounded by increased FLAIR signal, most in keeping with vasogenic oedema.  There is associated mass effect with effacement of adjacent sulci and leftward midline shift of 4 mm at the level of the third ventricle.  The mass demonstrates restricted diffusion and reduced ADC. There is an area of restricted diffusion involving the adjacent cortex also.

MRI spectroscopy in voxel at the medial margin of the lesion demonstrates depleted NA-A, decreased choline, increased lactate and slightly increased myo-inositol.  Possible increased amino acids.

There is an old infarct in the left parieto-occipital region extending to the ventricular surface, with ex-vacuo dilatation of the posterior aspect of left lateral ventricle.

Annotated image

Slightly hyperdense (on pre-contrast CT) peripherally enhancing lesion (blue dotted line) is associated with meningeal enhancement (yellow arrows, MRI, T1 C+) and is surrounded by vasogenic oedema. The centre of the lesion demonstrates vivid restricted diffusion (MRI, DWI) (green arrow). 

Case Discussion

This case illustrates the typical appearances of a cerebral abscess, and although the diagnosis is certainly suggested on the basis of CT appearance and clinical scenario (this patient had recently had a chest infection and had been experiencing fevers for the past week), and MRI confirmed the diagnosis, and the patient went on to have a craniotomy. 

Microbiology revealed Streptococcus anginosus group (milleri group) infection. 

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Case information

rID: 19468
Case created: 12th Sep 2012
Last edited: 1st Oct 2016
Inclusion in quiz mode: Included

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