Abstract
Lambert Eaton myasthenic syndrome (LEMS) is a rare disorder of the neuromuscular junction. The representative clinical triad consists of proximal muscular weakness, areflexia and autonomic dysfunction. The diagnosis is based on the clinical findings confirmed by voltage-gated calcium channels antibody titer and neurophysiology. We present a 69 year old male with prostate adenocarcinoma and 30 years history of smoking, referred for muscle weakness in the lower limbs and difficulty to climb the stairs.