[Analysis of Small Cell Lung Cancer with Paraneoplastic Limbic Encephalitis].

Background: The aim of this study was to investigate the clinical features of paraneoplastic limbic encephalitis (PLE) with small cell lung cancer (SCLC) and improve clinical diagnosis and treatment.

Methods: The clinical data of 15 patients with SCLC combined with PLE from January 1980 to May 2017 were collected from Beijing Union Hospital. Their symptoms and laboratory data were analyzed and the prognosis of the patients was followed.

Results: PLE is a rare disease, the incidence rate in SCLC is about 0.842%. The data may be underestimated because of misdiagnose or missed diagnosis; High incidence crowd of the disease is the middle-aged male smoker, the tumor-node-metastasis (TNM) stages of them are later than others; Typical neurological symptoms include varying degrees of short-term memory loss, seizures and varying degrees of mental disorders; neurological symptoms usually occur before the onset of cancer or respiratory symptoms appear, an average of about 2 months be taken from onset to diagnosis; Serum antibody (anti-Hu, GABA-R-Ab), cerebrospinal fluid, head magnetic resonance imaging (MRI) and electroencephalogram (EEG) of the patients has abnormalities; Videography, especially computed tomography (CT) is a good means of screening the primary tumor, pathology diagnosis mainly rely on bronchoscopy; The treatment of primary tumors can be more effective in alleviating the nervous system symptoms than immunotherapy.

Conclusions: Paraneoplastic limbic encephalitis is a rare paraneoplastic syndrome in nervous system caused by malignant neoplasms often characterized by facial neurological symptoms. The disease are usually associated with lung cancer (especially SCLC). Its nervous system symptoms occur earlier than the tumor diagnosis. Early diagnosis and treatment for primary tumors will increase the benefit.