Mu-heavy chain disease associated with systemic amyloidosis.

mu-heavy chain disease (HCD) is very rare, with only 30 cases reported in the literature. We report a patient with mu-HCD associated with systemic amyloidosis. The diagnosis of mu-HCD was based on findings of mu-heavy chain fragments in the serum, Bence Jones proteinuria and vacuolated plasma cells in the bone marrow. To our knowledge, this is the third case in which systemic amyloidosis led to the patient's death.