A 69-year-old man with a rare case of lymphoma-type alpha-chain disease was admitted to the hospital with marked cervical and inguinal lymph node swelling. Lymph node biopsy showed marked infiltration of plasma cells, plasmacytoid cells and immunoblastoid cells, alone or in combination. Immunoelectrophoresis and immunoselection identified alpha-chain in the serum and urine. The site of alpha-chain synthesis was extensively studied in the whole body, and the immunoperoxidase technique eventually demonstrated the presence of alpha-chains in the cytoplasm of infiltrating malignant cells in the lymph nodes. No infiltrating malignant cells were found in other organs or tissues, including those of the digestive and respiratory tracts.