Lymphoma & related disorders

Mature B cell neoplasms

Splenic B cell lymphomas and leukemias

Splenic diffuse red pulp

Editorial Board Member: Genevieve M. Crane, M.D., Ph.D.
Editor-in-Chief: Debra L. Zynger, M.D.
Emily M. Hartsough, B.S.
Pawel Mroz, M.D., Ph.D.

Last author update: 8 February 2019
Last staff update: 23 January 2023

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PubMed Search: Splenic diffuse red pulp small B cell lymphoma

Emily M. Hartsough, B.S.
Pawel Mroz, M.D., Ph.D.
Page views in 2022: 2,081
Page views in 2023 to date: 968
Cite this page: Hartsough E, Mroz P. Splenic diffuse red pulp. website. Accessed May 29th, 2023.
Definition / general
  • Mature splenic B cell lymphoma characterized by diffuse infiltration of the splenic red pulp with small, monomorphous B lymphocytes
  • Bone marrow sinusoids and peripheral blood are often also involved acommonly with a villous morphology
  • Diagnosis should be restricted to those fulfilling major features; if in doubt, the terminology splenic B cell lymphoma / leukemia, unclassifiable is preferred
Essential features
  • Provisional entity within the category of splenic B cell lymphoma / leukemia, unclassifiable, along with hairy cell leukemia variant (Swerdlow: WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues, 4th Edition, 2017)
  • Indolent disease course, often diagnosed at clinical stage IV disease (involvement of spleen, bone marrow and peripheral blood)
  • Microscopically characterized by small to intermediate sized B lymphocytes diffusely invading the red pulp cords
    • Intrasinusoidal involvement can be seen on bone marrow biopsy
    • Peripheral blood smear reveals villous cytology
  • Important to differentiate from hairy cell leukemia, hairy cell leukemia variant and splenic marginal zone lymphoma
  • Provisional entity under splenic B cell lymphoma / leukemia, unclassifiable (WHO classification)
  • Splenic lymphoma with villous lymphocytes
ICD coding
  • ICD-O: 9591/3 - splenic diffuse red pulp small B cell lymphoma
  • Incidence:
    • Rare, < 1% of all non-Hodgkin lymphomas
    • 10% of splenic B cell lymphomas
  • Age: usually > 40 years (median 65.5 - 77 years)
  • Sex: M > F (ratio varies between 1.6 - 2.4) (Discov Med 2012;13:253)
Clinical features
  • Massive splenomegaly is seen in most cases
  • Typically stage IV disease (blood and bone marrow involvement)
  • Splenic hilar lymph nodes are frequently reported (Haematologica 2010;95:1122)
  • B symptoms (rare)
  • Erythematous and pruritic skin papules (10% of cases) (Haematologica 2010;95:1122)
  • Requires constellation of clinical features, peripheral blood smear, marrow and spleen histology, immunophenotyping and cytogenetics
  • Splenectomy may be is required for confirmation of diagnosis (Arch Pathol Lab Med 2014;138:1295)
Radiology description
  • Massive splenomegaly
Prognostic factors
  • Indolent but incurable disease
  • Must differentiate from similar diseases, as it has a good prognosis but is often resistant to conventional chemotherapy that is effective for hairy cell leukemia, hairy cell leukemia variant and splenic marginal zone lymphoma (Blood Res 2018;53:74)
  • Cases with mutations in NOTCH1, MAP2K1 and TP53 have been reported to have shorter progression free survival (Am J Surg Pathol 2016;40:192)
Case reports
Gross description
  • Diffusely enlarged spleen with a homogenous beefy red-brown cut surface
  • Wedge shaped subcapsular infarcts (Blood Res 2018;53:74)
Gross images

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Diffusely enlarged spleen

Microscopic (histologic) description
Cytology description
  • Small to medium, monomorphic lymphocytes with round oval nuclei and compact, clumped chromatin
  • Occasionally distinct, small nucleoli
Peripheral smear description
  • Small villous lymphocytes with clumped chromatin and a smooth nuclear outline
  • Cytoplasm is basophilic with broad based cytoplasmic extensions in a polar distribution (Blood 2008;111:2253)
Peripheral smear images

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Neoplastic villous lymphocytes

Positive stains
Flow cytometry description
Molecular / cytogenetics description
Differential diagnosis
Splenic diffuse red pulp small B cell lymphoma Splenic marginal zone lymphoma Hairy cell leukemia Hairy cell leukemia variant
Frequency of non-Hodgkin lymphoma 0.5% < 2% 2% 0.4%
Anemia and thrombocytopenia Uncommon Present (autoimmune) Present Present
Monocytopenia Absent Absent Present (characteristic) Absent (leukocytosis with lymphocytosis and normal monocyte count)
Blood smear Broad based polar cytoplastic extensions (similar to splenic marginal zone lymphoma) Polar villi and inconspicuous nucleoli Reniform or oval nuclei, circumferential long villi, inconspicuous nucleoli Abundant circumferential villi and prominent nucleoli
Spleen Diffuse involvement of red pulp with cord and sinusoid infiltration, blood lakes may be present, absence of white pulp involvement Micronodular pattern with white pulp replacement, marginal zone differentiation Diffuse infiltrate in red pulp cords, effaced white pulp, formation of blood lakes Red pulp involved, blood lakes uncommon, effaced white pulp with absent white pulp follicles.
TRAP - Variable + -
Bone marrow Predominantly intrasinusoidal infiltrate, interstitial and nodular infiltration have been reported; no lymphoid follicles have been reported Nodular interstitial and intrasinusoidal infiltrate; occasionally, tumor cells surround reactive follicles Dense infiltrate, fibrosis Interstitial and sinusoidal infiltrate
Flow cytometry CD25-
CD103 variable
Immunohistochemistry Annexin A1-
Annexin A1-
DBA-44 variable
Annexin A1+
Annexin A1-
Genetic mutation CCND3
VH1 / 2
BRAF V600E (~100%) MAP2K1
Cytogenetics Uncommon
del 7q
trisomy 18
del 17p
del 7q
trisomy 3 (less common)
del 13q
del 7q (uncommon)
del 17p
Treatment Splenectomy Splenectomy
Purine analogs
Partial response to purine analogs
Board review style question #1

A 60 year old man presents with abdominal discomfort and generalized weakness. CT of the chest / abdomen / pelvis reveals massive splenomegaly. Splenectomy demonstrates a monomorphic diffuse infiltration of the red pulp. Peripheral blood smear is shown above. Immunohistochemistry is positive for CD20 and DBA-44 and negative for CD25, CD103, CD123 and Annexin A1. What is the most likely diagnosis?

  1. Hairy cell leukemia
  2. Hairy cell leukemia variant
  3. Splenic diffuse red pulp small B cell lymphoma
  4. Splenic marginal zone lymphoma
Board review style answer #1
C. Splenic diffuse red pulp small B cell lymphoma. While the 2017 revised WHO describes SDRPL as having a diffuse pattern of involvement of the red pulp with absence of the white pulp involvement (see table above), obliteration of the while pulp has been reported in the literature. As such, given the immunophenotype, a diagnosis of SDRPL is favored (Arch Pathol Lab Med 2014;138:1295, Haematologica 2010;95:1122, Discov Med 2012;13:253)

Comment here

Reference: Splenic diffuse red pulp small B cell Lymphoma
Board review style question #2
What is the most common treatment for splenic diffuse red pulp small B cell lymphoma?

  1. Chemotherapy
  2. Immunotherapy
  3. Radiation
  4. Splenectomy
Board review style answer #2
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