Tumefactive multiple sclerosis

Case contributed by Dr Andrew Dixon

Presentation

First seizure.

Patient Data

Age: 40
Gender: Male
CT

CT Brain

A region of hypoattenuation is seen within the left superior frontal gyrus with a 20mm ring enhancing lesion evident on the post contrast images. Remaining intracranial appearances are unremarkable. 

MRI

MRI Brain

MRI confirms a ring enhancing lesion within the left superior frontal lobe. The enhancing ring is slightly nodular and although it at first appears to be a complete ring on the axial images, the coronal images show that only the internal aspect of the lesions rim is enhancing (incomplete ring enhancement). There is no associated diffusion restriction. 

Elsewhere within the brain there are multiple non-enhancing T2/FLAIR white matter hyperintensities which are periventricular in distribution with some showing a linear alignment away from the ventricles (perivenular arrangement) known as Dawson's fingers suggestive of primary demyelination.  

Annotated image

Annotated image. 

Case Discussion

CT images show a 20mm ring enhancing lesion within the left superior frontal gyrus for which the differential diagnosis is broad (see mnemonic MAGIC DR), but most commonly would between cerebral metastasis, GBM and cerebral abscess

The MRI study shows the lesion to have incomplete ring enhancement on the coronal images and reveals multiple other non-enhancing T2/FLAIR white matter lesions with the characteristic Dawson's fingers appearance of multiple sclerosis.  

Occam's razor would favour the ring enhancing lesion to be tumefactive MS / active demyelination, but given the superficial location of the enhancing lesion and that it was not involving eloquent cortex, a biopsy was performed for confirmation. The pathologist was able to confirm active demyelination at this site. 

MICROSCOPIC DESCRIPTION: The biopsy pieces comprise cerebral cortex and white matter. Focally there is a well-demarcated white matter abnormality comprising a heavy infiltrate of macrophages accompanied by smaller numbers of lymphocytes and reactive astrocytes. Small blood vessels within this area are surrounded by a lymphocytic infiltrate. The Luxol fast blue stain shows loss of myelinated axons within this region. There is no atypia of the glial cell and mitotic figures are not seen. There is no necrosis. The features are of acute/active demyelination. There is no malignancy.

DIAGNOSIS/COMMENT:  Left frontal lesion, biopsy - Features of acute/active demyelination.

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Case information

rID: 21258
Case created: 13th Jan 2013
Last edited: 5th Sep 2015
Inclusion in quiz mode: Included

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