Analysis of corneal crystalline deposits in multiple myeloma

A 46-year old woman and a 59-year-old man had corneal crystals, multiple myeloma, and IgG kappa hypergammaglobulinemia. In one case, crystalline deposits were also present in the lens. In both patients there was a marked decrease in the amount of crystals during chemotherapy. The crystals within the cornea of one case were identified by light and electron microscopy in material obtained during a lamellar keratoplasty. The crystalline deposits were located only in the corneal epithelium, and their regular repeating internal arrangement was confirmed by monochromatic optical diffraction of electron micrographs of sections through them. By immunofluorescent and immunoperoxidase techniques, the crystals reacted positively for immunoglobulin and particularly IgG kappa chains.