Occurrence of acute large and edematous callosal lesions in neuromyelitis optica.
BACKGROUND
The corpus callosum is commonly involved in multiple sclerosis (MS), but the characteristics of callosal lesions in neuromyelitis optica (NMO) are unknown.ObjectiveTo reveal the features of callosal lesions in NMO in comparison to MS.


METHODS
We retrospectively reviewed the medical records and the brain magnetic resonance imaging films of 56 patients with MS and 22 patients with NMO.


RESULTS
In MS, 36 (64.3%) of 56 patients had callosal lesions, but only four patients had acute lesions. All such acute lesions were small, isolated and non-edematous, and the intensity was homotonic. Chronic lesions were observed in 34 patients with MS, and 32 (94%) of them presented small lesions located at the callosal lower margin ("hemi-oval pattern"). Meanwhile, four (18.2%) patients with NMO had callosal lesions, and three of them had acute lesions. Those acute lesions were multiple, large edematous ones with heterogeneous intensity ("marbled pattern"). In the chronic stage, the lesions shrank or disappeared.


CONCLUSIONS
Acute large, edematous callosal lesions occasionally occur in NMO. Similar to longitudinally extensive transverse myelitis, such callosal lesions may reflect severe edematous inflammation in NMO, and may provide additional evidence that the pathogenesis in NMO is different from that in MS.
Department of Neurology, Tohoku University Graduate School of Medicine, Sendai, Japan. mnakamura@em.neurol.med.tohoku.ac.jp
M
M
Nakamura
T
T
Misu
K
K
Fujihara
I
I
Miyazawa
I
I
Nakashima
T
T
Takahashi
S
S
Watanabe
Y
Y
Itoyama
D000208:Acute Disease; D000328:Adult; D001929:Brain Edema / Q000276:immunology / Q000473:pathology*; D003337:Corpus Callosum / Q000473:pathology*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000276:immunology / Q000473:pathology*; D009471:Neuromyelitis Optica / Q000276:immunology / Q000473:pathology*; D012189:Retrospective Studies; D012720:Severity of Illness Index
D007074:Immunoglobulin G