Small-intestine involvement in Waldenstrom's macroglobulinemia. Case report and review of the literature.

A patient presented with a three-year history of diarrhea and was found to have a monoclonal gammopathy (IgM lambda) and a malabsorption syndrome with dilatation of the small bowel. Small-intestinal biopsy revealed a homogeneous eosinophilic granular material between the epithelial cells. On electron microscopy this material was shown to consist of an electron-opaque background mixed wit radiolucent lipid sheres. Immunofluorescent studies showed the accellular material to consist entirely of IgM-reactive material. The patient's course and a review of the literature is presented.