We report a 35-year-old man with systemic lupus erythematosus and an associated protein-losing enteropathy that was most likely due to mesenteric venulitis or thrombosis. Evaluation of the patient's intestinal abnormality was aided by the use of magnifying endoscopy; the duodenal villi were lustrous and swollen and of various size, a pattern different from that previously described for intestinal lymphangiectasia. The patient was treated with corticosteroids, resulting in a good clinical response and return of the villi to normal shape and size.