Abstract Details

Adult-onset gLD are sometimes overlooked in the diagnostic evaluation of MS mimics.

To describe imaging characteristics and evaluate the applicability of the 2017 McDonald MRI criteria in patients with genetic leukodystrophies (gLD) initially misdiagnosed with multiple sclerosis (MS).

We reviewed MRIs on 17 patients referred to a single MS center 2000-2019, who initially carried an MS diagnosis but subsequently were confirmed to have a gLD (MS excluded). MRIs were scored on 4 typical, 10 suggestive, and 15 atypical/non-specific features of MS by an expert neuroradiologist blinded to diagnosis.

A variety of gLDs were diagnosed. All patients had baseline brain (11 gadolinium enhanced (GdE)) and 11 had baseline spinal cord (8 GdE) MRIs available for review. At least one finding typical of MS (periventricular, juxtacortical/cortical, or infratentorial lesions) or one feature suggestive of MS was seen in 16(94%) on baseline brain MRI, most commonly periventricular lesions (76%), MS-like (well delimited, ovoid, > 3mm) lesions (53%), Dawson fingers (29%), and black holes (29%). Atypical/non-specific features were seen in 13(76%), most commonly deep (71%), large/confluent (53%), and symmetric (53%) WMAs. 2(18%) had spinal cord lesions with typical features, one of which also had atypical features. At baseline, 6(35%) met criteria for dissemination in space (DIS) and 2(12%) met both DIS and dissemination in time (DIT). 9 follow-up brain and 7 follow-up spinal cord MRIs were available, after which 6(35%) met DIS (1 additional) and 4(24%) met DIS and DIT (2 additional).

Adult-onset gLD should be included in the differential diagnosis of MS in patients with atypical WMAs, specifically large/confluent WMAs, symmetric lesions, and deep white matter lesions. A quarter of patients with gLD had lesions satisfying 2017 McDonald MRI criteria, plus atypical lesions, emphasizing that the McDonald criteria should be applied with caution when lesions atypical of MS are present.