Case Report Overlapping of paraneoplastic limbic encephalitis and Lambert-Eaton myasthenic syndrome in a patient with small cell lung cancer: a rare case report

Paraneoplastic neurologic syndrome (PNS) is a rare group of disorders caused by nervous system damages in the setting of cancer unrelated to the tumor sites. It may affect one or more regions of the nervous system and occurred in less than 1 per 10,000 patients diagnosed with a malignancy. Patients with PNS may present symptoms or damages in the central and peripheral nervous system, the neuromuscular junction and muscle, which usually results in severely disabling. Nowadays, paraneoplastic limbic encephalitis (PLE) and Lambert-Eaton myasthenic syndrome (LEMS) are the most commonly reported types of PNS compared with the others. PLE is a rare disorder featured by personality change, seizure, irritability, and depression due to involvement of the limbic system secondary to an autoimmune response to neurons of the brain provoked by the antibodies. LEMS is well known as a classical paraneoplastic syndrome when the neuromuscular junction is affected. In this case, we report a case of paraneoplastic limbic encephalitis (PLE) and Lambert-Eaton myasthenic syndrome (LES) in an elderly Asian male with small cell lung cancer (SCLC).