[Amyloidosis of the A-kappa type].

A 73-year-old patient complained of increasing macroglossia and symmetrical enlargement of the submandibular region. A tongue biopsy showed typical deposits of amyloid by Congo red staining and polarization microscopy. Similar deposits were found in biopsy specimens of the submaxillary gland and the rectum. Electron microscopy revealed typical amyloid fibrils. With the indirect immunoperoxidase technique the amyloid was classified as being of immunoglobulin kappa-light-chain origin (A-kappa), because only anti-A kappa, but not anti-A lambda (several antisera of non-overlapping specificity), anti-ASc1 or anti-AF antisera were found to be reactive. Correspondingly, Bence Jones protein of the kappa type was found in the urine. In the bone marrow there was an increase in plasma cells of up to 10%. Cytostatic therapy with melphalan and methylprednisolone seemed to stop the progression of amyloid deposition.