COEXISTENCE OF PARANEOPLASTIC SENSORY NEURONOPATHY AND LAMBERT-EATON MYASTHENIC SYNDROME IN A SMALL-CELL LUNG-CANCER PATIENT

The present report is on a 72-year-old male patient with combined para neoplastic sensory neuronopathy (PSN) and Lambert-Eaton myasthenic syn drome (LEMS) with small cell lung cancer. He noticed a painful paresth esia of the legs which advanced over seven days, and both hands became numb and painful. Three months later, he was found to have small cell lung cancer by mediastinoscopic examination. PSN was diagnosed by cli nical symptoms and anti-Hu antibody, and LEMS was diagnosed by the wax ing phenomenon on an electromyogram (incremental in compound muscle ac tion potential up to 120%) and autoantibody against the presynaptic vo ltage-gated calcium channel. High titers of anti-Hu antibody were dete cted in the serum (1 : 12800) and cerebrospinal fluid (1 : 320). Altho ugh a partial response to chemoradiotherapy was obtained, the neurolog ic symptoms of PSN did not improve. The anti-Hu antibody titers obtain ed on five different occasions during the patient's clinical course di d not change. The patient died from respiratory arrest six months afte r the initiation of therapy. To the best of the authors' knowledge, th is combined form of disease, confirmed by both clinical and laboratory tests, is the rarest case ever to be reported.