title: Chronic myopathy due to immunoglobulin light chain amyloidosis.
abstract: Amyloid myopathy associated with a plasma cell dyscrasia is a rare cause of muscle hypertrophy. It can be a challenging diagnosis, since pathological findings are often elusive. In addition, the mechanism by which immunoglobulin light-chain deposition stimulates muscle overgrowth remains poorly understood. We present a 53-year old female with a 10-year history of progressive generalized muscle overgrowth. Congo-red staining and immunohistochemistry revealed perivascular lambda light chain amyloid deposits, apparent only in a second muscle biopsy. The numbers of central nuclei and satellite cells were increased, suggesting enhanced muscle progenitor cell formation. Despite the chronicity of the light chain disease, the patient showed complete resolution of hematologic findings and significant improvement of her muscle symptoms following autologous bone marrow transplantation. This case highlights the importance of early diagnosis and therapy for this treatable cause of a chronic myopathy with muscle hypertrophy.
authors: Section on Human Biochemical Genetics, Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA. manolii@mail.nih.gov
authors: Irini
authors: I
authors: Manoli
authors: Justin Y
authors: JY
authors: Kwan
authors: Qian
authors: Q
authors: Wang
authors: Elisabeth J
authors: EJ
authors: Rushing
authors: Maria
authors: M
authors: Tsokos
authors: Andrew E
authors: AE
authors: Arai
authors: Warner M
authors: WM
authors: Burch
authors: Angela
authors: A
authors: Dispenzieri
authors: Alexandra C
authors: AC
authors: McPherron
authors: William A
authors: WA
authors: Gahl
mesh_terms: D000328:Adult; D000686:Amyloidosis / Q000175:diagnosis / Q000276:immunology* / Q000628:therapy; D016026:Bone Marrow Transplantation; D005260:Female; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000097:blood / Q000378:metabolism*; D009135:Muscular Diseases / Q000175:diagnosis / Q000276:immunology* / Q000628:therapy; D010265:Paraproteinemias; D032496:Satellite Cells, Skeletal Muscle; D014182:Transplantation, Autologous
chemical_list: D007147:Immunoglobulin Light Chains