Lymphoma and plasma cell neoplasms
Plasma cell neoplasms
Plasmacytoma

Author: Genevieve M. Crane, M.D., Ph.D. (see Authors page)

Revised: 14 October 2017, last major update October 2017

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Plasmacytoma [title]

Cite this page: Crane, G.M. Plasmacytoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/lymphomaplasmacytoma.html. Accessed October 22nd, 2017.
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; see also Bone chapter
  • 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
Terminology
  • Solitary plasmacytoma of bone
  • Extraosseous (extramedullary) plasmacytoma
ICD-10 coding
  • C90.20 extramedullary
  • C90.30 solitary plasmacytoma of bone
Epidemiology
  • Bone and extramedullary tumors each comprise 3 - 5% of plasma cell neoplasms
  • Both are more common in men (65%), median age 55 years
Sites
  • 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
Bone:
  • 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
Diagnosis
  • Monoclonal plasma cells, less frequently plasmablastic or anaplastic morphology
  • Histologic findings are combined with laboratory and radiographic findings (below) showing absence of additional disease
Laboratory
  • 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
Radiology images

Images hosted on other servers:

Solitary plasmacytoma of bone with soft tissue expansion

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
Treatment
  • Local radiation therapy
Gross images

Images hosted on other servers:

Rare testicular plasmacytoma

Metastasis to myocardium

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

Images hosted on PathOut server:

Images contributed by Dr. Genevieve Crane, University of Rochester Medical Center:

Plasmacytoma

Plasmacytoma of bone with osteolytic destruction

Plasmacytoma, CD138+ and MUM1+

Plasmacytoma, CD79a± and CD20-

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



Images hosted on other servers:

Solitary plasmacytoma involving a rib

Extraosseous plasmacytoma involving the nasopharynx

Oral cavity plasmacytoma

Amyloid deposits in extraosseous plasmacytoma


Closeup of testicular tumor

Extramedullary plasmacytoma involving the small bowel

Colonic solitary plasmacytoma

Atypical plasma cells


Metastases to myocardium

Various images

Cutaneous plasmacytoma

Plasmablastic plasmacytoma

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

Images hosted on PathOut server:

Images contributed by Dr. Genevieve Crane, University of Rochester Medical Center:

Plasmacytoma touch preparation

Positive stains
Negative stains
Flow cytometry description
Molecular / cytogenetics description
Differential diagnosis
Board review 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 answer #1
D. Radiographs
Board review 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 answer #2
D. All of the above