Light-heavy chain deposition disease progressing to multiple myeloma.

Light chain deposition disease (LCDD) and light and heavy chain deposition disease (LHCDD) are rare clinical entities that have been associated with multiple myeloma, with monoclonal gammopathy of unknown significance (MGUS), or without any detectable protein abnormality. Renal failure is common, the diagnosis is difficult and prolonged survival is rare. The first patient with LHCDD and MGUS who progressed to multiple myeloma after 11 years is presented. A rising level of monoclonal IgA immunoglobulin, bone marrow plasmacytosis, and the presence of multiple bone marrow lesions on magnetic resonance imaging provided the first evidence of disease evolution. When management of serious complications permits a long survival, some patients with LCDD or LHCDD will develop multiple myeloma.