Monoclonal gammopathy of undetermined significance: why identification of these patients and assessment of their skeletons is important.

Monoclonal gammopathy of undetermined significance (MGUS) is a plasma cell disorder characterized by the presence of a serum monoclonal immunoglobulin (M-protein) at <or= 3 g/dL. It is an asymptomatic premalignant disorder that can progress to multiple myeloma and related B-cell disorders. Recent studies have suggested the association of MGUS with enhanced bone loss and debilitating skeletal complications, particularly vertebral compression fractures (VCFs) often leading to back pain. Early identification of MGUS and evaluation of bone status will facilitate prophylactic treatment with bisphosphonates to increase bone density and likely reduce the risk of fractures as well as identify patients with VCFs who might benefit from early surgical intervention. With proper diagnostic and treatment strategies, these patients will experience improved outcomes and quality of life.