Extramedullary Plasmacytoma

Updated: Dec 01, 2015
  • Author: Suzanne R Fanning, DO; Chief Editor: Emmanuel C Besa, MD  more...
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Overview

Background

A plasmacytoma is a discrete, solitary mass of neoplastic monoclonal plasma cells in either bone or soft tissue (extramedullary). The types of plasmacytomas are as follows:

  • Soft-tissue or nonosseous extramedullary plasmacytoma (EMP)
  • Solitary bone plasmacytoma (SBP)
  • Multifocal form of multiple myeloma
  • Multiple myeloma
  • Plasmablastic sarcoma

To simplify, solitary plasmacytomas can be divided into 2 groups according to location:

  • Plasmacytoma of the skeletal system (SBP)
  • Extramedullary plasmacytoma (EMP)

Diagnostic criteria for solitary bone plasmacytoma (SBP)

Criteria for identifying solitary bone plasmacytoma (SBP) vary among authors. [1, 2, 3] Some include patients with more than one lesion and elevated levels of myeloma protein and exclude patients whose disease progressed within 2 years or whose abnormal protein persisted after radiotherapy. With the use of magnetic resonance imaging (MRI), flow cytometry, and polymerase chain reaction (PCR), the currently accepted criteria are as follows [4, 5]

  • Single area of bone destruction due to clonal plasma cells
  • Bone marrow plasma cell infiltration not exceeding 5% of all nucleated cells
  • Absence of osteolytic bone lesions or other tissue involvement (no evidence of myeloma)
  • Absence of anemia, hypercalcemia, or renal impairment attributable to myeloma
  • Low, if present, concentrations of serum or urine monoclonal protein
  • Preserved levels of uninvolved immunoglobulins

Extramedullary plasmacytoma (EMP): Diagnostic criteria

Diagnostic criteria for extramedullary plasmacytoma (EMP) are as follows [6, 7, 8] :

  • Tissue biopsy showing monoclonal plasma cell histology
  • Bone marrow plasma cell infiltration not exceeding 5% of all nucleated cells
  • Absence of osteolytic bone lesions or other tissue involvement (no evidence of myeloma)
  • Absence of hypercalcemia or renal failure
  • Low serum M protein concentration, if present

For excellent patient education resources, see eMedicineHealth's patient education article Myeloma.

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Pathophysiology

A plasmacytoma can arise in any part of the body. A solitary bone plasmacytoma (SBP) arises from the plasma cells located in the bone marrow, whereas extramedullary plasmacytoma (EMP) is thought to arise from plasma cells located in mucosal surfaces. [9] Both represent a different group of neoplasms in terms of location, tumor progression, and overall survival rate [10, 11] Some authors suggest a solitary bone plasmacytoma (SBP) represents marginal cell lymphomas with extensive plasmacytic differentiation. [11] Both solitary bone plasmacytoma (SBP) and extramedullary plasmacytoma (EMP) do, however, share many of the biologic features of other plasma cell disorders.

Cytogenetic studies show recurrent losses in chromosome 13, chromosome arm 1p, and chromosome arm 14q, as well as gains in chromosome arms 19p, 9q, and 1q. [12] Interleukin 6 (IL-6) is still considered the principal growth factor in the progression of plasma cell disorders. [5]

The specific roles of surface markers, adhesion molecules, and angiogenesis in solitary plasmacytoma need to be studied further.

In a study by Kumar et al, high-grade angiogenesis in the solitary bone plasmacytoma (SBP) was associated with increased progression to multiple myeloma and shorter progression-free survival. Some have postulated that solitary bone plasmacytoma (SBP) may be considered an intermediate step in the evolution from monoclonal gammopathy of undetermined significance to multiple myeloma. [5, 13]

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Epidemiology

Frequency

United States

Solitary bone plasmacytoma (SBP) affects fewer than 5% of patients with plasma cell disorders. [4, 5] In a series of 263 patients with MGUS, 2 patients (0.8%) developed solitary bone plasmacytoma (SBP). [14]

Extramedullary plasmacytoma (EMP) represents approximately 3% of all plasma cell neoplasms.

Mortality/Morbidity

See the list below:

  • Solitary bone plasmacytoma (SBP) develops into multiple myeloma in 50-60% of patients. [15] Median overall survival time is 10 years. [16]
  • Extramedullary plasmacytoma (EMP) progresses to multiple myeloma in 11-30% of patients at 10 years. Overall survival rate at 10 years is 70%.

Sex

See the list below:

  • Solitary bone plasmacytoma (SBP) has a male-to-female ratio of 2:1.
  • Three fourths of extramedullary plasmacytoma (EMP) cases involve males. [6, 9, 16, 17, 18]

Age

See the list below:

  • The median age of patients with either solitary bone plasmacytoma (SBP) or extramedullary plasmacytoma (EMP) is 55 years.
  • This median age is 10 years younger than patients with multiple myeloma. [6, 9, 16, 17, 18]
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