Neuromyelitis Optica Spectrum Disorder Presenting With Organizing Pneumonia: A Case Report and Literature Review.

Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory disease of the central nervous system (CNS) that can result in severe neurological sequelae. Aquaporin-4, a cause of complement-mediated inflammation in NMOSD, is expressed on alveolar epithelial cells and in the CNS, and organizing pneumonia (OP) is recognized as an extra-CNS symptom in NMOSD. We herein present a case of NMOSD following OP. The patient initially presented with area postrema syndrome, and the coexistence of OP made the diagnosis of NMOSD challenging. A review of previously reported cases of NMOSD with OP suggests that careful attention to area postrema syndrome as an onset symptom is needed for the early diagnosis and treatment of NMOSD in male and older patients with OP.