Crystal-storing histiocytosis and crystalline tissue deposition in multiple myeloma

Systemic distribution of crystal-storing histiocytes, increasing in number, and widespread crystalline tissue deposition were found in a 75-year-old man with a 5-year history of IgG-kappa-type multiple myeloma associated with corneal opacity and chronic renal failure. Characteristic crystalline inclusions were present not only in myeloma cells but also in cornea, epithelial cells of glomeruli, tubuli, Bowman's capsules, and choroid plexus. Histiocytes had particularly infiltrated the renal interstitium. These inclusions were positive by immunofluorescence for kappa light and gamma heavy chains. By electron microscopy, the inclusions were filled with fine crystalline hexagonal columns, each possessing a core structure. Of various factors generally considered responsible for renal failure in multiple myeloma, marked infiltration of histiocytes and the nephrotoxic effects of light chain appeared most relevant in the present case.