Plasma cell disorder

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Plasma cell disorders

Overview

Classification

Monoclonal gammopathy of undetermined significance (MGUS)
Malignant monoclonal gammopathies
Multiple myeloma
Malignant lymphoproliferative disorders
Chronic lymphocytic leukemia
Heavy-chain diseases
Cryoglobulinemia
Primary amyloidosis

Differentiating Plasma Cell Disorder

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Nazia Fuad M.D.


Overview

Plasma cell disorders are a diverse type of blood disorders characterized by the presence of a monoclonal paraprotein in the serum or urine. Monoclonal plasma cells are present in the bone marrow or, rarely, in other tissues. Plasma cell disorders include monoclonal gammopathy of undetermined significance (MGUS), multiple myeloma (MM), lymphoplasmacytic lymphoma/ Waldenstrom macroglobulinemia (LPL/WM), lymphoproliferative disorders, smoldering multiple myeloma (SMM); solitary or extramedullary plasmacytoma, amyloidosis, and POEMS syndrome (Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal protein, and Skin changes).The plasma-cell disorders are characterized by the proliferation of a single clone of plasma cells that produces a homogeneous monoclonal (M) protein. these disorders have been defined by the International Myeloma Working Group.1 In 2006.

Classification

Monoclonal gammopathies of undetermined significance (MGUS)

  • Benign (IgG, IgA, IgD, IgM, and, rarely, free light chains)
  • Associated neoplasms or other diseases not known to produce monoclonal proteins
  • Biclonal and triclonal gammopathies
  • Idiopathic (Bence Jones proteinuria)

Malignant monoclonal gammopathies

  • Multiple myeloma (IgG, IgA, IgD, IgE, and free light chains)
    • Symptomatic multiple myeloma
    • Smoldering multiple myeloma
    • Plasma-cell leukemia
    • Non-secretory myeloma
    • IgD myeloma
    • POEMS syndrome: polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes (osteosclerotic myeloma)
    • Solitary plasmacytoma of bone
    • Extramedullary plasmacytoma
  • Malignant lymphoproliferative disorders

Chronic lymphocytic leukemia

Heavy-chain diseases (HCDs)

    • γHCD
    • αHCD
    • μHCD

Cryoglobulinemia

Primary amyloidosis (AL)

Differential Diagnosis

Disease IgM IgG IgA IgE IgD Monoclonal Ig level SFLC Bone marrow plasma cells Other criteria
IgM MGUS + < 3gm/dl N/A <10% No end-organ

damage

Non igM MGUS + + < 3gm/dl N/A <10% No end-organ

damage

Smoldering MM + + > 3gm/dl N/A 10-60%
  • No myeloma-defining event
  • No CRAB features
Light chain MGUS <500 mg/24 hrs (urine) Free kappa or lambda light chain

Abnormal ratio (<0.26 or >1.65)

Increase in involved light chain concentration

<10% No end-organ damage
Active symptomatic Multiple myeloma + + + + >3gm/dl >100 >60%
  • ≥1 myeloma-defining event
  • CRAB features
Waldenstrom macroglobulinemia + Variable N/A >10%
  • Evidence of organ/tissue damage.
  • Anemia,
  • Hepatosplenomegaly
Solitary Plasmacytoma + <3mg/dl Abnormal in 47% cases Normal
  • Solitory bone lesion due to plasma cell tumor
  • Preserved levels of uninvolved immunoglobulins
  • No anemia, hypercalcemia or renal disease
Primary amyloidosis <3md/dl Light chains of immunoglobulines <10%
  • No bone lesions,

Myeloma-defining events: ≥60% clonal plasma cells on BM examination; serum involved:uninvolved FLC ratio of ≥100; >1 focal lesion on MRI ≥5 mm

CRAB features: elevated calcium (>11 mg/dL), renal insufficiency (serum creatinine >2 mg/dL or creatinine clearance <40 mL/min), anemia (Hb <10 g/dL or 2 g/dL < normal), bone disease (≥1 lytic lesions on skeletal radiography, CT, or PET-CT , SFLC: serum free light chains, kappa and lambda immunoglobulin light chains.

The normal κ:λ ratio is 0.26 to 1.65 (17,18). A κ:λ ratio of <0.26 strongly suggests the presence of a of plasma cells that are producing clonal λ free light chains. Ratio >1.65 suggests production of clonal κ free light chains.

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