A case of IgA (kappa type) myeloma complicated by fractures of the bones and 
hyperviscosity syndrome is presented. A 56-year-old woman who had been followed 
as an outpatient with diabetes mellitus for about 16 years, developed multiple 
myeloma. She also showed symptoms and signs of hyperviscosity syndrome; 
hemorrhagic diathesis, blurred vision and episodes of transient ischemic attacks 
of the brain, and fractures of the bones by small powers of trauma. At autopsy, 
almost all bones showed infiltration of multiple myeloma of IgA-kappa type and 
severe osteoporosis accompanied with proliferation of osteoclasts. The 
association of IgA myeloma with hyperviscosity syndrome and/or bone destruction 
was discussed. The "serum hyperviscosity syndrome" has been described clinically 
as the triad of bleeding, visual signs and symptoms, and neurologic 
manifestations. And this syndrome has been associated frequently with 
macroglobulinemia of Waldenström, occasionally with immunoglobulin (Ig) G 
myeloma, rarely with IgA myeloma, and with other dysproteinemia. Myeloma is also 
characterized by extensive bone destruction and is accompanied by susceptibility 
to fracture, although Waldenström's macroglobulinemia, acute leukemia or chronic 
leukemia are rarely associated with bone resorption. The present report 
describes a patient with IgA myeloma complicated by hyperviscosity syndrome and 
multiple bone fractures.