A case of isolated brainstem bright spotty lesion in a patient with AQP4-positive NMOSD

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune central nervous system disorder mainly associated with aquaporin-4 antibodies. While it primarily affects the optic nerves and spinal cord, brainstem involvement may occur. A twenty-eight years old woman with medical background of anorexia nervosa and cutaneous neurofibromatosis, was referred to our center for progressive gait disorders with a tetrapyramidal syndrome. MRI revealed isolated T2-hyperintense lesions of the medullo-spinal junction, characterized by brighter spotty T2-hyperintense areas within it, known as bright spotty lesion, and showing heterogenous enhancement. Further investigations led to the diagnosis of AQP4 + Neuromyelitis Optical Spectrum Disorder. The clinical and radiological evolution were favorable after immunotherapy. Our case illustrates the variety of the NMO spectrum and alerts clinicians to evoke this diagnosis in front of insidious symptoms and rare radiological presentation.