Lymphoma and plasma cell neoplasms
B cell disorders

Topic Completed: 1 February 2011

Revised: 6 February 2019

Copyright: 2001-2017,, Inc.

PubMed Search: post-rituximab lymphoma

Nikhil Sangle, M.D.
Page views in 2019: 231
Page views in 2020 to date: 10
Cite this page: Sangle N. Post-rituximab (anti-CD20 antibody). website. Accessed January 17th, 2020.
Definition / general
  • Rituximab is an anti-CD20 antibody widely used to treat lymphoma
  • Loss of CD20 expression is common at relapse of aggressive B cell lymphoma treated with rituximab (Br J Haematol 2002;119:412)
  • Post rituximab, tumors may show loss of CD20 expression with proliferation of plasmacytoid cells, transformation to classic Hodgkin lymphoma or transformation to an anaplastic large cell lymphoma-like undifferentiated lymphoma (Cancer Sci 2009;100:54)
  • Recurrent CD20 negative cases are often clonally related to pre-rituximab tumor (Leuk Lymphoma 2002;43:2335)
  • Bone marrow specimens may contain T cell aggregates that suggest relapse, so ordering immunostains is important (Am J Clin Path 1999;112:844)
  • CD79a and Pax-5 should be used as the first line B lineage-specific markers to detect CD20 negative mature B cell lymphomas; if negative, OCT.2 or BOB.1 may be useful (Am J Clin Path 2006;126:534)
  • CD20 antigen may reappear after relapse of CD20 negative tumor (Haematologica 2007;92:e1)
Microscopic (histologic) images

Images hosted on other servers:

Reappearance of CD20
antigen after relapse of
CD20 negative tumor

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