Amyloidosis, a potentially fatal disease, is characterized by an abnormal deposition of autologous proteins. Heart, liver, kidneys, lung, thyroid, skin and the gastrointestinal tract can be involved; in this last case mucosal alterations or disturbances of the motility leading to pseudo-obstruction, bleeding, diarrhea and malabsorption can be present. However, the data concerning the possible gastrointestinal presentations of amyloidosis are scanty and heterogeneous. We report the case of a patient presenting severe gastrointestinal symptoms caused by a megaduodenum. The patient was thoroughly investigated and lesions appeared limited to the upper gastrointestinal tract in the absence of a systemic disorder. However, at follow up the patient developed cardiac dilatation and bioptic samples revealed the presence of amyloidosis.