Lymphoma and plasma cell neoplasms
B cell lymphoma subtypes
Large B cell lymphoma with IRF4 rearrangement

Editorial Board Member: Genevieve M. Crane, M.D., Ph.D.
Editor-in-Chief: Debra Zynger, M.D.

Topic Completed: 27 March 2019

Revised: 29 March 2019

Copyright: 2019, PathologyOutlines.com, Inc.

PubMed Search: Large B cell lymphoma with IRF4 rearrangement[TI] OR lymphoma of Waldeyer's ring[TI]
Page views in 2019 to date: 163
Cite this page: Balakrishna J. Large B cell lymphoma with IRF4 rearrangement. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/lymphomairf4rearrangement.html. Accessed June 16th, 2019.
Definition / general
  • Uncommon subtype of large B cell lymphoma characterized by strong expression of IRF4 / MUM1
  • Commonly associated with IRF4 gene rearrangement
Essential features
  • Children and young adults
  • Lymph nodes of head and neck or Waldeyer ring are affected
  • Diffuse, diffuse and follicular or follicular pattern
  • Medium to large cells
  • Germinal center B cell phenotype with diffuse IRF4 / MUM1 expression
  • Most cases show IRF4 rearrangement
Terminology
  • Lymphoma of Waldeyer ring
ICD coding
Epidemiology
  • Rare subtype accounting for 0.05% of diffuse large B cell lymphomas
  • Primarily affects children and young adults
  • Equal gender incidence (Blood 2011;118:139)
Pathophysiology
Clinical features
  • Isolated lymph node enlargement
  • Tonsillar enlargement
Diagnosis
  • Biopsy of the involved lymph node / tissue with immunophenotyping and confirmation using FISH analysis for IRF4 rearrangement
  • Strong, diffuse positivity for IRF4 / MUM1 in neoplastic cells
  • Young age of the patient, head and lymph node / Waldeyer ring location
Prognostic factors
  • Favorable response to treatment with immunochemotherapy
Case reports
Treatment
  • Responds well to chemoimmunotherapy with or without radiation
Gross description
  • Involved lymph node / tonsil is enlarged
  • Firm, fleshy homogenous mass
Gross images

Images hosted on other servers:

Oropharyngectomy specimen

Microscopic (histologic) description
Microscopic (histologic) images

Contributed by Jayalakshmi Balakrishna, M.D.

Diffuse pattern

Expansile follicles

Diffuse effacement
with medium
sized cells


Medium sized atypical lymphoid cells

Round to irregular nuclear contours and conspicuous nucleoli

Follicular pattern


CD20

BCL2

BCL6

MUM1

CD21

Positive stains
Negative stains
Flow cytometry description
  • Low side light scatter and moderate forward light scatter
  • Pan B cell markers and CD10 positive
  • Surface immunoglobulin light chain positive with monoclonal pattern
Flow cytometry images

Images hosted on other servers:

CD20+, kappa restricted

Molecular / cytogenetics description
Molecular / cytogenetics images

Contributed by Itziar Salaverria, Ph.D.

FISH break apart probe for IRF4



Images hosted on other servers:

FISH for IRF4 / DUSP22 break apart probe

Karyotype

Sample pathology report
  • Lymph node, left cervical, excision:
    • Large B cell lymphoma with IRF4 rearrangement; see synoptic report
Differential diagnosis
Board review question #1
An 8 year old boy has tonsillar enlargement. Which stain is most likely positive in the neoplastic cells?



  1. CD1a
  2. CD3
  3. MUM1
  4. TdT
Board review answer #1
C. MUM1

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Board review question #2
Which is the common partner gene of IRF4 in large B cell lymphoma with IRF4 rearrangement?

  1. BCL2
  2. c-Myc
  3. IgH
  4. IgK
Board review answer #2
C. IgH

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