Abnormal, bilaterally symmetric “butterfly-shaped” diffuse subcortical and deep white matter T2/FLAIR high signal centered in the posterior and inferior cerebrum, involving white matter tracts, including the corpus callosum, and with leading edge enhancement (active demyelination) in a young male patient, typical for adrenoleukodystrophy.  

The differential diagnosis of dysmyelinating white matter disease includes:

• metachromatic leukodystrophy bilateral symmetrical and confluent periventricular deep white matter lesions sparing the subcortical U-fibers particularly around the frontal horns and atria with characteristic butterfly pattern.
• Alexander disease: with predominant frontal involvement and then progression posteriorly. 
• Canavan disease: diffuse, bilateral with involvement of the subcortical U-fibers as well as macrocephaly and markedly increased NAA and NAA/Cr ratio on MRS.

The case is courtesy of Dr Hassana Ibrahim and Dr Mohammed A ElBeilay.