Proliferation monoclonal plasma cells that make monoclonal protein
Multiple myeloma accounts for 1% of all cancers in US, 10% of all hematologic cancers in US
Risk Factors
Median age 66
Monoclonal Gammopathy Undetermined Significance (MGUS)--> monoclonal protein elevation < 3g/dl and no other target organ dysfxn (sometimes peripheral neuropathy or hypercoag); progresses to myeloma ~1%/y
Smoldering Myeloma--> monoclonal protein > 3g/dl, 10% plasma cells in BM, but no target organ dysfxn; progresses to myeloma 10%/y
Sometimes progressive motor/sensory peripheral neuropathy--> weakness, numbness, pain
Sometimes recurrent infections
Eye symptoms/blurred vision, confusion--> concerning for hyperviscocity - usually from mono-clonal IgM spike (Waldenstroms, w/large pentamers--> sludging), though can be IgA or IgG
Physical Exam Findings
Edema
Sometimes areas of focal bone pain
Sometimes confusion
Sometimes decreased vision
Tests
Initial labs: anemia, elevated creatinine, elevated total protein (TP), TP-albumin greater than 4, elevated calcium
SPEP, plasma free light chains, serum immunofixation (type and quantification of monoclonal protein)
Bone marrow biopsy
Bone survey to assess for lytic lesions
Myeloma: 10% plasma cells in BM, > 3g/dl monoclonal protein, and at least 1 CRAB finding/sx; Smoldering myeloma: 10% plasma cells in BM, > 3g/dl monoclonal protein, but no CRAB findings; MGUS: < 10% plasma cells, < 3g/dl monoclonal protein, no CRAB