Clinical characteristics of paraneoplastic neurological syndrome related to different pathological lung cancers

BACKGROUND: Paraneoplastic syndrome is a distant effect caused by malignant tumors, which is related to the production of cellular immune response. The nervous system is the most common involved system of paraneoplastic syndrome. It is easy to be misdiagnosed. Lung cancer is the most common cancer relating to paraneoplastic neurological syndrome (PNS). METHOD: This study retrospectively analyzed clinical data of patients with the combination of PNS and lung cancer between January 2005 and March 2021 at Qilu Hospital of Shandong University, China. RESULTS: A total of 111 patients were diagnosed with lung cancer complicated with PNS. A total of 95 (85.6%) cases had neurological symptoms as the first symptom. Sixty‐three cases had the pathological results. A total of 43 (68.3%) of small cell lung cancer (SCLC) were diagnosed. PNS patients diagnosed with SCLC included peripheral neuropathy (15 cases, 34.9%). PNS patients diagnosed with non‐small cell lung cancer (NSCLC) included peripheral neuropathy (6 cases, 30%) and limbic encephalitis (6 cases, 30%). Anti‐Hu is popular in patients with SCLC (12 cases, 42.9%) and NSCLC (6 cases, 40%). CONCLUSIONS: Most patients with PNS had neurological symptoms as the first symptom. It was more common in males. It had a higher incidence in SCLC. Peripheral neuropathy was the most common PNS associated with SCLC, followed by Lambert‐Eaton syndrome. Peripheral neuropathy and limbic encephalitis were the most common PNS associated with NSCLC. Anti‐Hu is the most common antibodies both in SCLC and NSCLC. Tumor markers do not have significant difference between different pathological types.