Paraneoplastic neuromyelitis optica spectrum disorder associated with stomach carcinoid tumor.

Neuromyelitis optica (NMO), or Devic's syndrome, is an autoimmune central nervous system demyelinating disorder primarily affecting the spinal cord and the optic nerves. It is characterized by the presence of NMO antibodies, alongside clinical and radiological findings. NMO and NMO-spectrum disorders (NMO-SD) have been reported in autoimmune disorders, and are infrequently described as a paraneoplastic syndrome with cancers of lung, breast, and carcinoid tumors of the thyroid. We report a patient who presented with severe vomiting, blurring of vision, vertigo, diplopia, left hemiparesis and hemisensory loss and ataxia. She was found to have a longitudinally-extensive demyelinating lesion extending from the medulla to the upper cervical spinal cord on MRI. Her gastric endoscopy revealed carcinoid tumor of the stomach, and classic paraneoplastic antibodies in the serum were negative. She had extremely high serum gastrin level and high titer of NMO IgG autoantibody. The patient made an excellent recovery with tumor resection and immunotherapy, with both clinical and radiological improvement. On rare instances, NMO or NMO-SD may present as a paraneoplastic neurological syndrome associated with carcinoid tumor of the stomach.