Muscle Involvement in Multiple Myeloma: Report of a Patient Presenting Clinically as Polymyositis

Abstract

Although bone pain is common in multiple myeloma (MM), muscular symptoms, especially myalgias, may be rare. We describe a patient who presented with generalised myopathy and elevated creatine kinase (CK) suggestive of polymyositis. Routine blood tests showed raised viscosity and marked rouleaux formation in the peripheral blood film. A serum protein electrophoresis showed IgG Lambda paraproteinemia with immunoparesis. A sternal bone marrow aspirate and a bone marrow biopsy concurrently obtained from the right posterior iliac crest showed considerable (15–20%) marrow infiltration with plasma cells confirming a diagnosis of multiple myeloma. A review of the literature suggests that generalised myopathy and elevated CK associated with MM have not been reported in the past. We believe this is the first reported case of MM presenting as polymyositis.

Keywords:

• Multiple myeloma
• polymyositis