Pathological study of subacute autoimmune encephalopathy with anti-AQP4 antibodies in a pregnant woman

A pregnant woman with extensive brain lesions on magnetic resonance imaging was tested positive for anti-aquaporin4 (AQP4) antibodies. An open biopsy of the left temporal lobe showed pathological changes in both the white and gray matter. Hematoxylin and eosin, Klüver-Barrera, and myelin basic protein staining results were indicative of demyelination in the white matter. Loss of AQP4 and glial fibrillary acidic protein was observed in the white matter, and this finding is consistent with the neuropathological findings of neuromyelitis optica spinal lesions. Moreover, loss of AQP4 was observed in the gray matter. The presence of anti-AQP4 antibodies, and the pathology, led to the diagnosis of anti-AQP4 antibodies-related encephalopathy.