<prompt> A 55-year-old male presents with renal failure, bone pain for 7 years and osteolytic lesions on X-ray. Serum electrophoresis shows M spike and 35 plasma cells with aberrant protein expression. What is the diagnosis? E. REPEAT 2013MGUSMultiple myelomaSmoldering myelomaPlasma cell leukemia  <response>: Ref: Harrison s Principles of Internal Medicine, 18th edition. Pages 937-942: CMDT 2013, Pages 527-529Explanation:MULTIPLE MYELOMAMalignant proliferation of plasma cells derived from a single clone.Clinical Featureso Lytic hone lesionso Anemia with high ESRo Rnulex formation of red cellso Renal failureo Infectionso Hypercalcemia.Classical Triad of MMo Marrow plasmacytosis 10o Lytic bone lesionso Serum andor urine M component.Diagnosiso Monoclonal plasma cells k, l, light chain restricted in BM or as a tumor solitary plasmacytoma.o End organ damage--lytic bony lesions, anemia, hypercalcemia, renal failure with paraproteinemia mostly IgG or IgAo Serum electrophoresis for M band b,go Urine Bence Jones protein for light chainso Non secretory myeloma--No paraproteins, poor prognosis.o X-rays axial skeleton--Skull, spine, long bones, ribs for lytic lesionso PET or MRI useful for early lesionso Radionuclide scan NOT useful.DD: Smoldering myeloma and MGUS.Treatment:o Thalidomidelenolidamide high dose dexamethasone.o Bortezomib.o Autologous hematopoietic SCT.o Localized RT tor vertebral collapse, o Bisphosphonates for malignant hypercalcemia beware of osteonecrosis jaw!. PrognosisStage32 microglobulinAlbuminSurvivalStage 13.5 mgL5.5 gdL5 yearsStage 23.5-5.5 mgL Stage 35.5 mgL 2 years Smouldering myeloma Asymptomatic myelomaMGUSM protein in serum 30gL30gLBM plasma cells 10 10SymptomsNil End organ damageNilNilPlasma Cell LeukemiaPlasma cells 2000pL in 2 of patients.Seen in IgD 12 t and IgE 25 myelomas. 