Fig. 3

a Plasma cells with fine needle-shaped intracellular crystalline depositions were frequently seen in the bone marrow (Wright’s stain, ×1,000 magnification). b The red-colored cytoplasmic inclusions and eccentric mononucleosis were frequently observed in the clot sections (hematoxylin and eosin staining, (b) × 400 magnification) (inset, ×1,000 magnification). c The plasma cells were stained strongly for the kappa light-chain. Some fine needle-shaped crystalline depositions were also observed in the cells (×400 magnification) (inset, ×1,000 magnification). d The deep-red-colored cytoplasmic inclusions with fine needle-shaped structures considered to be crystalline deposits (Masson's trichrome stain, ×1000)