Malignant thymoma with dysautonomia and disordered neuromuscular transmission.

A 42-year-old man had prominent dysautonomia accompanied by clinical and electrophysiological features of both myasthenia gravis and the Lambert-Eaton myasthenic syndrome. Antiacetylcholine receptor antibodies were present in high titer. Invasive thymoma was found at thymectomy; later, a solitary metastasis to the spleen required a splenectomy. Complete remission followed surgery. There was evidence of antibody activity directed against postsynaptic acetylcholine receptors, presynaptic somatic motor terminals, and autonomic effector junctions. To our knowledge, the association of thymoma with a myasthenia gravis-Lambert-Eaton overlap syndrome has not been reported previously.