[Lambert-Eaton syndrome and small cell cancer. Etiopathogenic considerations apropos of 2 cases].

The authors report two cases of Lambert-Eaton myasthenic syndrome associated with small cell lung carcinoma. Following the observations, the clinical diagnosis of this syndrome is considered. We discuss the autoimmune pathogenesis and the relation between paraneoplastic syndrome and small cell cancer. This syndrome is caused by autoantibodies that block the voltage-dependent calcium channels at motor nerve terminals. Small cell carcinoma cells appear to express calcium channels, suggesting that autoantibody production may be triggered by tumor calcium channels determinants. The autoimmune paraneoplastic syndrome theory refers to cross-antigenicity.