Multiple Myeloma

The following is from Resource (1) below:

Multiple myeloma (MM) is characterized by the neoplastic proliferation of plasma cell clones that produce monoclonal immunoglobulin. These plasma cell clones proliferate in the bone marrow causing skeletal damage, a hallmark of MM. Other disease related complications include hypercalcemia, renal insufficiency, anemia, and infections. MM accounts
for approximately 1.8% of all cancers and slightly more than 17% of hematologic malignancies in the United States. The American Cancer Society has estimated that 30,280 new MM cases will occur in the United States in 2017, with an estimated 12,590deaths. [Resource (1) below]

The following is from Resources (2) and (3) below:

Multiple myeloma (MM) [Link is to Resource (2) below] is a debilitating malignancy that is part of a spectrum of diseases ranging from monoclonal gammopathy of unknown significance (MGUS) [Link is to Resource (3) below]) to plasma cell leukemia.

Solitary plasmacytoma (SP) [Link is to Resource (4) below] is an early-stage plasma cell malignancy that is in between monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM) along the spectrum of plasma cell disorders. [1. A plasmacytoma is a discrete, solitary mass of neoplastic monoclonal plasma cells. SPs can be divided into 2 groups according to location:

  • Solitary bone plasmacytoma (SBP) – These occur most commonly in the vertebrae

  • Extramedullary plasmacytoma (EMP) – These encompass all nonosseus SPs; they can occur in any soft tissue but the upper airway tract, including the sinuses, is the most common site.

The following is from Resource (3) below:

MGUS represents two thirds of all plasma cell dyscrasias. The incidence increases with age. MGUS occurs in up to 5.3% of the population older than 70 years. [11]

The annual risk of progression [of MGUS] to multiple myeloma (MM), Waldenström macroglobulinemia (WM), amyloidosis (AL), or other lymphoproliferative disorders is 1% with IgG or IgA MGUS. This risk is 1.5% with IgM MGUS. A high plasma cell labeling index suggests active disease. Circulating plasma cells are an adverse predictor of progression.

The rest of what follows are all excerpts from Resource (2) below.

First described in 1848, Multiple Myeloma (MM) is characterized by a proliferation of malignant plasma cells and a subsequent overabundance of monoclonal paraprotein (M protein).

MM is characterized by neoplastic proliferation of plasma cells involving more than 10% of the bone marrow.

MM can range from asymptomatic to severely symptomatic with complications requiring emergent treatment. Presenting signs and symptoms of MM include the following:

  • Bone pain
  • Pathologic fractures
  • Spinal cord compression (from pathologic fracture)
  • Weakness, malaise
  • Bleeding, anemia
  • Infection (often pneumococcal)
  • Hypercalcemia
  • Renal failure
  • Neuropathies

The International Myeloma Workshop guidelines for standard investigative workup in patients with suspected MM include the following [Resource (5) below. See also Resource (4) below on screening tests for multiple myeloma from Mayo Clinic Laboratories]

  • Serum and urine assessment for monoclonal protein (densitometer tracing and nephelometric quantitation; immunofixation for confirmation)
  • Serum free light chain assay (in all patients with newly diagnosed plasma cell dyscrasias)
  • Bone marrow aspiration and/or biopsy
  • Serum beta2-microglobulin, albumin, and lactate dehydrogenase measurement
  • Standard metaphase cytogenetics
  • Fluorescence in situ hybridization
  • Skeletal survey
  • MRI

Imaging studies

  • Simple radiography for the evaluation of skeleton lesions; skeletal survey, including the skull, long bones, and spine
  • MRI for detecting thoracic and lumbar spine lesions, paraspinal involvement, and early cord compression
  • PET scanning in conjunction with MRI potentially useful

Resources:

(1) NCCN Guidelines® Insights Multiple Myeloma, Version 3.2018
Featured Updates to the NCCN Guidelines [Abstract] [Full Text HTML] [Full Text PDF].

(2) Multiple Myeloma Updated Jan 11, 2018 from Emedecine.Medscape.com

(3) Monoclonal Gammopathies of Undetermined Significance Updated: Jul 06, 2017 from Emedecine.Medscape.com

(4) Solitary Plasmacytoma Updated: May 15, 2018 from Emedecine.Medscape.com.

(4) Laboratory Screening Tests For Multiple Myeloma [the link is to an awesome clickable PDF – you can click on every test in the flow chart and be taken to more information on that test] from Mayo Clinic Medical Laboratories.

(5) Consensus recommendations for standard investigative workup: report of the International Myeloma Workshop Consensus Panel 3 [Medline Abstract] [Full Text HTML] [Full Text PDF].  2011 May 5;117(18):4701-5. doi: 10.1182/blood-2010-10-299529. Epub 2011 Feb 3.

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