Presentation
7 days left upper limb weakness.
Patient Data
An area of subcortical white matter hypoattenuation in the posterior right frontal lobe with preserved overlying cortex and no evidence of hemorrhage appears to be a solitary lesion.
CTA normal (not shown). No convincing enhancement on the arterial phase.
In the region of abnormality identified on CT in the posterior right frontal lobe periventricular white matter, multiple T1 hypointense and T2/FLAIR hyperintense lesions are surrounded by edema, many demonstrating peripheral enhancement and mild rim diffusion restriction. No abnormal elevation of cerebral blood volume on MR perfusion. MR spectroscopy demonstrates elevated choline and some elevated lactate (not shown).
Additional smaller lesions are demonstrated in the posterior frontal lobe on the left and right anterior temporal lobe. There is an additional non-enhancing but diffusion-restricting callososeptal lesion of the anterior body of the corpus callosum and a non-enhancing non-diffusion restricting focus in the right parahippocampal gyrus.
No infratentorial or convincing cervical cord lesions.
Conclusion:
Imaging features favor demyelination.
The patient had a CT chest-abdomen-pelvis which was normal. They were started on prednisolone and natalizumab.
Marked improvement with resolution of edema and reduction in enhancement and diffusion restriction. Small punctate regions of signal loss on SWI are noted.
Case Discussion
Tumefactive demyelination should be considered particularly in younger patients where the likelihood of metastatic disease is much lower. Identifying thin regular peripheral enhancement, often incomplete (open-ring) is particularly helpful.