Protein-losing enteropathy due to secondary amyloidosis of the gastrointestinal tract.

A case of a 71 year old woman who experienced weight loss, diarrhea and edema due to protein-losing enteropathy caused by amyloidosis secondary to rheumatoid arthritis is described. Amyloid deposits were found in the systemic organs, specifically in the bowel. The arterioles were massively involved within the laminae propriae and many were narrowed considerably due to amyloid deposits. Ulcerative lesions, which were accompanied with the ruptured arterioles, were also found. Lymphangiectasia was present in the submucosa, subserosa and mesenterium. The mesenteric lymphatic vessels were deposited markedly with amyloid. The principal cause of the protein loss might be related to the increased capillary permeability to plasma proteins and the exudation through an inflamed mucosa. Functional disruption of the lymphatic flow in the bowel and mesenterium might also participate in the mechanisms of the protein loss. Evidence in this study supports the theory that lymphatic disorders in some patients with gastrointestinal amyloidosis are one of the important factors in the pathogenesis of protein-losing enteropathy.