Lymphoma and plasma cell neoplasms
Non-Hodgkin lymphoma
General

Author: Nikhil Sangle, M.D. (see Authors page)

Revised: 3 April 2017, last major update February 2011

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PubMed Search: B cell non-hodgkin lymphoma

Cite this page: Non-Hodgkin lymphoma - General. PathologyOutlines.com website. http://pathologyoutlines.com/topic/lymphomaNHLgeneral.html. Accessed May 24th, 2017.
Definition / general
  • Clonal lymphoproliferative disorder
  • Heterogenous neoplasms; diagnosis of Non-Hodgkin lymphoma (NHL) gives far less information than type of NHL
Epidemiology
  • Increasing incidence over past 40 years for unknown reasons
  • 50,000 new cases in U.S. per year, many HIV related
Etiology
  • Putative cell of origin is known for most B cell NHLs but not most T cell NHLs
  • Often associated with a cytogenetic translocation that puts a proto-oncogene or apoptotic gene next to a gene that is constitutively active in lymphocytes
Clinical features
  • 80% are B cell, NK are rare
  • All are monoclonal as determined by light chain restriction or antigen receptor gene rearrangement (immunoglobulin or T cell receptor)
  • Characteristic patterns of tissue involvement occur, such as follicular lymphomas in B cell areas, T cell lymphomas in paracortical zones
  • Most tumors are widely disseminated at diagnosis, requiring systemic therapy for cure; thus, staging is not as important as in Hodgkin lymphoma
  • In adults, most common subtypes are follicular lymphoma, diffuse large B cell lymphoma, CLL / SLL, multiple myeloma
  • In children, most common subtypes are Burkitt or Burkitt-like, lymphoblastic leukemia / lymphoma, large B cell lymphoma and anaplastic large cell lymphoma; in children, follicular and marginal zone lymphoma are uncommon; tumors are usually extranodal, aggressive, often leukemic; but better survival than adults
  • Risk factors include immunodeficiency (primary or secondary), autoimmune disorders (Sjogren, rheumatoid arthritis, Hashimoto thyroiditis), viruses (HIV, ATLV, KSHV / HHV8, HTLV-1), Helicobacter pylori infection, radiation, chemotherapy
  • More likely than Hodgkin lymphoma to be extranodal, disseminated, involve peripheral blood, bone marrow, GI, skin or CNS
  • Less likely than Hodgkin lymphoma to have B symptoms (only 20% versus 40% in Hodgkin lymphoma) or have mediastinal involvement (except that mediastinal involvement is common in lymphoblastic and mediastinal large B cell lymphoma)
  • Poor prognostic factors, based on International Prognostic Index (IPI): age at diagnosis > 60 years, presence of B symptoms, ECOG / Zubrod performance status 2 - 4 vs. 0 - 1, elevated serum LDH, more than 1 nodal or extranodal site of disease, advanced vs. localized disease
Treatment
  • See particular tumors; addition of rituximab (anti-CD20 antibody) to most B cell NHL treatment regimens has led to improved survival
Cytology description
  • Sensitivity and specificity of diagnosis with fine needle aspiration increases with use of flow cytometry
  • Cytology is a good diagnostic tool in most lymphomas except marginal zone lymphoma and Hodgkin lymphoma (Arch Pathol Lab Med 2000;124:1792)
Negative stains
Differential diagnosis
  • Florid immunoblastic proliferations of infectious mononucleosis or other viral infections, particularly in children, resemble lymphoma
  • Autoimmune lymphoproliferative syndrome patients with Fas or FasL deficiency may develop giant lymphadenopathy resembling EBV+ post transplant lymphoproliferative disease (Am J Surg Pathol 1999;23:829)