A 38 year old woman presented portal hypertension and proteinuria. Liver biopsy showed peliosis hepatis with non amyloid deposits, reactive with anti-kappa antibody by immunofluorescence, along the sinusoids and in the Disse spaces. There are identical deposits along glomerular and tubular basement membranes. An underlying pleomorphic lymphoplasmocytic malignancy, analogous to Waldenström's macroglobulinemia was found, but without serum or urine monoclonal Ig. Biosynthesis experiments showed that the bone marrow cells synthesized abnormally short light chains with a larger apparent molecular weight when secreted than in the cytoplasmic extracts, presumably because of glycosylation. These results suggest a causal relationship between production of abnormal Ig chains and tissue deposition.