Gastric cancer complicated by paraneoplastic neurological syndrome which presented with extremity numbness: a case report

Background Paraneoplastic neurological syndromes refer to a group of neurological disorders, which occur as distant effects of malignant tumors and are not caused by metastasis, nutritional disorders, or side effects of antitumor drugs. Case presentation A 70-year-old woman complained of a 1-month history of extremity numbness. Upon presentation to our hospital, she had worsening numbness, and experienced staggering and falling. Physical examination revealed diminished tendon reflexes in both lower limbs, stocking and glove-type abnormal sensation, and left-sided dominant high-steppage gait due to weakness of the bilateral tibialis anterior muscles. Blood tests indicated anemia, and upper gastrointestinal endoscopy revealed gastric cancer, leading to laparoscopic distal gastrectomy. A nerve conduction velocity test showed demyelinating peripheral neuropathy. Further blood tests and imaging studies ruled out nutritional disorders, such as vitamin deficiency, diabetes-related diseases, connective tissue diseases, and central nervous system metastasis, leading to the suspicion of paraneoplastic neurological syndrome. After laparoscopic distal gastrectomy, the progression of symptoms stopped, and with intravenous high-dose immunoglobulin and steroid therapy, the symptoms improved to only minor numbness in the peripheral limbs as of the 18-month follow-up. As of the 2-year follow-up, there has been no cancer recurrence or metastasis. Conclusions When paraneoplastic neurological syndrome is suspected, early diagnosis and a multidisciplinary approach, including surgical treatment, are important before irreversible neurological damage occurs.