Distinct from PMD, patients with genetic metabolic leukodystrophies such as X-linked adrenoleukodystrophy (X-ALD) or metachromatic leukodystrophy (MLD), due to mutation in the ATP binding cassette subfamily D member 1 gene and the arylsulfatase A gene respectively, may present at any age with extensive gadolinium-enhancing tumefactive lesions, associated with inflammatory demyelination, neuronal loss, and blood-brain barrier leakage [62]. Here, ARSA is linked to metachromatic leukodystrophy.