Intestinal pseudo-obstruction, myasthenia gravis, and thymoma.

Two patients presented with abdominal pain, recurrent vomiting, weight loss, and constipation secondary to intestinal pseudo-obstruction. Both patients had symptoms and signs of myasthenia gravis, acetylcholine receptor antibodies, and thymoma. In one patient inflammatory cell infiltrates and occasional degenerate neurons were found in the myenteric plexus. The gastrointestinal symptoms resolved during treatment with pyridostigmine. The close temporal relationship between the onset of the gastrointestinal symptoms and the detection of myasthenia gravis and thymoma suggests that intestinal pseudo-obstruction can be a paraneoplastic syndrome associated with thymoma.