A case of IgA kappa light chain deposition disease and combined adult Fanconi syndrome with auer rod-like intracytoplasmic inclusions in plasma cells and proximal renal tubular cells]

We report a case of IgA kappa light chain deposition disease and combined adult Fanconi syndrome with Auer rod-like intracytoplasmic inclusions in plasma cells and proximal renal tubular cells in a 54-yr-old female. Cytochemical stainings revealed a strong acid phosphatase activity of the inclusions and weak periodic acid-Schiff positivity, whereas the reactions for peroxidase and alpha-naphthyl acetate esterase were negative. An immunostaining verified IgA-kappa inside the plasma cells. Kidney biopsy revealed Bence Jones cast nephropathy with kappa light chain positivity, and Congo red staining was negative. Electron microscopy showed needle-shaped crystals located in tubular epithelial cells.