Bone marrow neoplastic

Bone marrow - plasma cell and lymphoid neoplasms

Plasma cell neoplasms


Topic Completed: 1 October 2017

Minor changes: 23 April 2021

Copyright: 2002-2021,, Inc.

PubMed Search: Plasmacytoma [title]

Genevieve M. Crane, M.D., Ph.D.
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Cite this page: Crane GM. Plasmacytoma. website. Accessed October 25th, 2021.
Definition / general
  • Solitary lesion of clonal plasma cells that are cytologically, immunophenotypically and genetically similar to plasma cell myeloma
  • Solitary plasmacytoma of bone: localized bone tumor consisting of monoclonal plasma cells with no other radiographic lesions and no evidence of other bone marrow involvement
  • Extraosseous (extramedullary) plasmacytoma: localized tumor of plasma cells (not in bone)
Essential features
  • Monoclonal plasma cells, no associated clonal B cell population, isolated lesion without evidence of additional bone marrow plasmacytosis
  • Solitary plasmacytoma of bone
  • Extraosseous (extramedullary) plasmacytoma
ICD coding
  • C90.20 extramedullary
  • C90.30 solitary plasmacytoma of bone
  • Bone and extramedullary tumors each comprise 3 - 5% of plasma cell neoplasms
  • Both are more common in men (65%), median age 55 years
  • Extraosseous: 80% in upper respiratory tract (15% spread to cervical lymph nodes)
  • Other: GI, lymph nodes (Am J Clin Pathol 2001;115:119), bladder, CNS, breast, thyroid, testis, parotid, skin
  • Bone:
    • Areas of active hematopoiesis
    • In order of decreasing frequency: vertebrae, ribs, skull, pelvis, femur, clavicle, scapula, rare in distal long bones
Clinical features
  • Most present with bone pain
  • Vertebral lesions may cause cord compression
  • Palpable mass due to soft tissue extension
  • Up to 2/3 progress to myeloma or additional plasmacytomas; 1/3 remain disease free for > 10 years following local (radiation) control
  • 5% may have multiple or recurrent plasmacytomas but no evidence of myeloma

Extraosseous (clinical features depend on site):
  • Rhinorrhea, epistaxis, nasal obstruction
  • Approximately 15% progress to myeloma, 70% are disease free at 10 years
  • 25% have local recurrence, may spread to regional lymph nodes or metastasize to distant sites
  • Monoclonal plasma cells, less frequently plasmablastic or anaplastic morphology
  • Histologic findings are combined with laboratory and radiographic findings (below) showing absence of additional disease
  • M protein in serum or urine (absent or lower than in myeloma):
    • Bone: approximately 50%, usually IgG
    • Extraosseous: 20%, often small, IgA
  • No CRAB (hypercalcemia, renal failure, anemia, additional bone lesions)
  • Unlike myeloma, normal levels of uninvolved immunoglobulins
  • Monitor free light chain to measure progression
Radiology description
  • MRI may be preferred method to exclude additional bone lesions
  • Solitary bone lesions are usually purely lytic with a narrow zone of transition to normal bone
  • Abnormalities may persist after successful treatment
Prognostic factors
Bone - poor prognostic features (in some series):
  • Older patients
  • Plasmacytoma > 5 cm
  • Persistence of M protein following radiotherapy
  • Low polyclonal immunoglobulins (also raises concern for myeloma)
  • Osteopenia
Case reports
  • Local radiation therapy
Microscopic (histologic) description
  • Similar to myeloma, may contain mature, immature, plasmablastic or anaplastic plasma cells
  • Amyloid deposits may appear in extraosseous tumors as pink amorphous material with scattered multinucleated giant cells
Microscopic (histologic) images

Contributed by Kelly Magliocca, D.D.S., M.P.H.
Solitary plasmacytoma of bone

Solitary plasmacytoma of bone

Contributed by Genevieve M. Crane, M.D., Ph.D.


Plasmacytoma of bone with osteolytic destruction

Plasmacytoma, CD138+ and MUM1+

Plasmacytoma, CD79a± and CD20-

Plasmacytoma, core biopsy, H&E and kappa / lambda ISH

Cytology description
  • Similar to myeloma
  • Mature plasma cells: oval with abundant basophilic cytoplasm, perinuclear hof, round eccentric nuclei, "clock face" chromatin and indiscernible nucleoli
  • Immature plasma cells: higher nuclear / cytoplasmic ratio, more abundant cytoplasm and hof region compared to plasmablastic, more dispersed chromatin, often prominent nucleoli
  • Plasmablastic: less abundant cytoplasm with little or no hof region, fine reticular chromatin, large nucleus ( > 10 microns) or large nucleolus ( > 2 microns) (Blood 1998;91:2501)
  • Pleomorphic: multinucleated, polylobated
    • Rare cases may have small, lymphoid appearing plasma cells or plasma cells with marked nuclear lobation
  • Morphologic features:
    • Mott cells / morula cells: multiple grape-like cytoplasmic inclusions comprised of crystalized Ig
    • Russell bodies: hyaline intracytoplasmic and intranuclear inclusions
    • Flame cells: vermillion staining glycogen rich IgA in cytoplasmic projections
    • Gaucher-like cells / thesaurocytes: overstuffed fibrils
    • Cytoplasmic crystals: occasional in myeloma, common in adult Fanconi syndrome
    • Dutcher bodies: pale staining nuclear inclusions, single and usually large, more common in IgA myeloma
Cytology images

Contributed by Genevieve M. Crane, M.D., Ph.D.

Plasmacytoma touch preparation

Positive stains
Negative stains
Flow cytometry description
Molecular / cytogenetics description
Differential diagnosis
  • Cutaneous or GI plasmacytoma particularly difficult to differentiate from marginal zone lymphoma, may not be possible
  • Large cell lymphoma with immunoblastic or plasmablastic features
  • Marginal zone lymphoma, lymphoplasmacytic lymphoma: may have plasmacytoid features, but more extensive sampling may reveal B cell component; CD20 expression by lymphocytes or plasmacytoid cells; clonal B cell population by flow; molecular or cytogenetic features of marginal zone or lymphoplasmacytic lymphoma
  • Plasma cell myeloma: must be excluded by radiographs, bone marrow biopsy
  • Radiographically: may mimic metastatic tumor, Langerhans cell histiocytosis
  • Reactive plasma cell infiltrate: polyclonal for kappa and lambda
Board review style question #1
The best way to distinguish plasma cell myeloma from solitary plasmacytoma is:

  1. CD19 expression
  2. Cytogenetics demonstrating a t(11;14) translocation
  3. Plasmablastic features
  4. Radiographs
Board review style answer #1
D. Radiographs

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Reference: Plasmacytoma
Board review style question #2
When considering the diagnosis of a solitary plasmactyoma in a cervical lymph node, which factor(s) are most important to consider?

  1. Lymph node involvement by myeloma
  2. Nodal marginal zone lymphoma with extensive plasmacytic differentiation
  3. Potential spread from the upper respiratory tract
  4. All of the above
Board review style answer #2
D. All of the above

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Reference: Plasmacytoma
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