Abstract
Neurological paraneoplastic syndrome is a relatively rare condition in patients with malignant tumors. Recently, it has been reported that anti-Aquaporin 4 (AQP4) antibody is highly specific for neuromyelitis optica. The patient was a 76-year-old man. He underwent right upper lobectomy for squamous cell carcinoma of the lung. Although the immediate postoperative course was uneventful, neurological symptoms became apparent from postoperative day (POD) 4. Magnetic resonance imaging showed longitudinally extended edematous lesions in the spinal cord, and a cerebrospinal fluid examination was positive for anti-AQP4 antibody, leading to the diagnosis of paraneoplastic neuromyelitis optica. Despite multiple rounds of steroid pulse therapy and plasma exchange, the neurological symptoms worsened and the patient died on POD 46. The development of neuromyelitis optica in the early postoperative period could be related to the influence of surgical stress or epidural anesthesia.