- Lambert-Eaton Myasthenic Syndrome - Lambert-Eaton myasthenic syndrome (LEMS) is a rare disorder of neuromuscular transmission. It was first described in association with lung cancer. Research has demonstrated an autoimmune etiology. The initial presentation can be similar to that of myasthenia gravis, but the progression of the two diseases have some important differences. For the purpose of ...www.emedicine.com/EMERG/topic292.htm