Lambert-Eaton syndrome with large-cell neuroendocrine carcinoma of the lung.

Lambert-Eaton syndrome (LES) is an immune-mediated disorder of the presynaptic neuromuscular junction due to the blocking effect of the voltage-gated calcium channel (VGCC) antibodies. Small-cell lung cancer (SCLC) is the most common cause of LES. We report an unusual case of LES associated with large-cell neuroendocrine carcinoma (LCNEC) of the lung. In this case, clinical symptoms of LES predated the diagnosis of LCNEC by 6 years. After tumor resection, the patient experienced clinical and electrophysiological improvement. In addition, he had a decrease in VGCC antibody titer from 130 to 80 pmol/L. The onset of LES can be prolonged, and tumor surveillance should continue in these cases.