Hematogenous neoplasms
OLD Plasmacytoma

Topic Completed: 1 December 2013

Minor changes: 12 June 2020

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PubMed Search: Plasmacytoma[TI] spleen

Page views in 2020 to date: 2
Cite this page: Mansouri J. OLD Plasmacytoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/oldtopics/spleenplasmacytoma.html. Accessed August 8th, 2020.
Definition / general
  • Localized mass (neoplasm) of plasma cells found in tissues other than bone
  • Primary or secondary tumors are rare in spleen
  • Primary tumors may cause massive splenomegaly and rupture
  • Term "plasmacytoma" may sometimes refer to an isolated plasma cell mass in setting of advanced plasma cell myeloma
  • Plasmacytoma in this section refers to primary plasma cell mass (extramedullary, extraosseous) without known clinical evidence of plasma cell myeloma (i.e. no bone marrow involvement)
  • Solitary plasmacytoma of bone refers to localized plasma cell neoplasm of bone without evidence of plasma cell myeloma
  • 3 - 5% of plasma cell neoplasms (male > female), median age 55 years
  • 80% in upper respiratory tract, primarily oropharynx, nasopharynx, larynx
  • Also GI tract, skin, lymph nodes, various other sites including thyroid, breast, brain
  • Rare in spleen
Clinical features
  • Site specific (e.g. splenomegaly)
  • Usually requires tissue for definitive diagnosis (e.g. at splenectomy)
  • Need to rule out plasma cell myeloma, including bone marrow involvement and systemic disease (myeloma can occasionally present as plasmacytoma)
  • Small monoclonal spike (M protein - usually IgA) in 20% of patients
Prognostic factors
  • Usually indolent course; may progress to plasma cell myeloma in 15% of cases
  • Regional occurrences in up to 25% of cases
  • May occasional metastasize
Case reports
  • Radiation therapy localized to site of involvement
Gross images

Images hosted on other servers:

Well circumscribed nodule in spleen

Microscopic (histologic) description
  • Mature plasma cells, plasmablasts
  • May be binucleated or multinucleated
  • Nodular aggregates or diffuse infiltration of plasma cells in red pulp
Positive stains
Negative stains
Flow cytometry description
  • Plasma cells may express cytoplasmic monotypic light chain immunoglobulin
  • Expression of CD20 or μ rather than γ heavy chain by neoplastic cells may favor lymphoma over plasmacytoma
Differential diagnosis
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