Recurrent diencephalic involvement as the sole manifestation of anti-aquaporin 4 antibody-positive disorder in an adult patient

Neuromyelitis optica spectrum disorders (NMOSD) may affect the brain, particularly the cerebral hemispheres and diencephalon. Recognition of the clinical manifestations arising from hemispheric or diencephalic involvement as a presenting feature of NMOSD may be challenging in clinical practice. This case report describes a patient with recurrent diencephalic involvement as the sole manifestation of NMOSD. A 68-year-old female presented with cognitive decline and transient behavioral changes with hallucinations and childish behavior for several months. Additionally, she showed sleep cycle disturbance with enuresis, daytime hypersomnolence, and episodes of hypothermia and bradycardia. She had hyponatremia at admission. Brain MRI revealed a T2 hyperintense lesion in the diencephalon with contrast enhancement in the hypothalamus. A positive anti-aquaporin-4 cell-based assay confirmed the diagnosis of NMOSD after exclusion of other causes. She had a favorable response to immunosuppressors initially, but ten years later she had a relapse. Four months after the intensification of therapy, she was admitted with multiple brain abscesses and died. This case underscores recurrent hemispheric or diencephalic involvement as a unique phenotype of NMOSD with variable clinical presentations. Furthermore, it recapitulates the risk of opportunistic infections associated with the use of immunosuppressors in immune-mediated neurological disorders