Splenic Diffuse Red Pulp Small B-cell Lymphoma

Splenic Diffuse Red Pulp Small B-cell Lymphoma

Roberto N. Miranda, MD

Hematoxylin and eosin stain of small diffuse red pulp small B-cell lymphoma (SDRP SBCL) shows a diffuse effacement of the splenic architecture. No residual white pulp nodularity is noted.

SDRP SBCL. Hematoxylin and eosin stain shows tumor cells in cords image and sinuses image of spleen. Lymphocytes are small and round with compact chromatin and inconspicuous or absent nucleoli.



  • Splenic diffuse red pulp small B-cell lymphoma (SDRP SBCL)


  • Splenic marginal zone lymphoma, diffuse variant

  • Splenic B-cell lymphoma with villous lymphocytes

  • Splenic red pulp lymphoma with numerous basophilic villous lymphocytes

  • Lymphocytic lymphoma simulating hairy cell leukemia (obsolete term)


  • Mature B-cell neoplasm that involves peripheral blood, bone marrow, and spleen

  • Overlap with hairy cell leukemia variant

  • Provisional entity in 2008 WHO classification



  • Unknown

  • Cell of origin is a peripheral blood B cell of unknown stage and function



  • Incidence

    • Rare type of lymphoma; < 1% of all non-Hodgkin lymphomas

    • ˜ 10% of B-cell lymphomas diagnosed by splenectomy

      • ˜ 1% of chronic lymphoid leukemias

  • Age

    • Most patients are > 40 years

      • Median: 77 years

  • Gender

    • No obvious gender bias; may be slight male predominance


  • Clinically indolent

    • B symptoms rare

  • Splenomegaly; usually massive

  • Usually presents as stage IV with bone marrow involvement

  • Erythematous and pruritic skin papules in subset

  • Lymphadenopathy rare

Laboratory Tests

  • Low-level lymphocytosis in 76% of patients

    • Median lymphocyte count: 15.8 × 109/L

  • Thrombocytopenia (< 100 × 109/L) in 22%

  • Anemia (Hgb < 10 g/L) in 8%

  • Serum paraproteinemia is rare


  • Surgical approaches

    • Good clinical response following splenectomy


  • Clinically indolent but incurable disease

    • 63% of patients alive with median follow-up of 48 months in 1 study

    • Rare transformation to diffuse large B-cell lymphoma occurs


General Features

  • Marked splenomegaly with diffuse congested pattern

    • Median weight: 1,820 g


Histologic Features

  • Spleen

    • Diffuse infiltration of red pulp cords and sinuses with effacement of white pulp

  • Bone marrow

    • Intrasinusoidal pattern with or without interstitial or nodular pattern

Cytologic Features

  • Monomorphic population of round, small to intermediate-sized lymphocytes

    • Vesicular nuclei and occasional distinct nucleoli

    • Scant to moderate pale or eosinophilic cytoplasm; occasionally cells show plasmacytoid features

  • Peripheral blood and bone marrow smears

    • Lymphocytes show small, broad-based cytoplasmic projections (villi)

    • Villi are unevenly distributed around cell circumference



  • Pan-B-cell antigens(+), DBA.44/CD76(+)

  • p53(+) in subset

  • CD5(−), CD10(−), CD25(−), annexin-A1(−)

  • TRAP(−) by enzyme cytochemistry

Flow Cytometry

  • Characteristic immunophenotype

    • IgG(+), CD20(+), DBA.44/CD76(+), CD5(−), CD10(−), CD11c(−), CD25(−)

  • Subset of cases can be IgM(+), IgD(+), CD103(+)

  • Rare cases CD5(+) or CD123(+)


  • Complex cytogenetic abnormalities in ˜ 33% of cases

    • Del(7q), trisomy 3q, &/or trisomy 18 reported

  • Cytogenetic abnormalities are less frequent than in SMZL

  • t(9;14)(p13;q32)/PAX5-IgH reported in subset of cases

Molecular Genetics

  • Low frequency of somatic mutations in IgH variable region genes

  • IgH variable region use similar to classical HCL

  • Overrepresentation of VH3-23 and VH4-34

  • No bias of VH1.2 usage of genes (similar to SMZL)

  • P53 gene mutations in subset


Hairy Cell Leukemia

  • Diffuse splenic red pulp involvement

  • Diffuse replacement of bone marrow

    • “Fried egg” cytologic appearance

  • Blood and bone marrow smears

    • Lymphocytes evenly surrounded by “hairy” cytoplasmic projections

  • Blood: Pancytopenia with monocytopenia

  • Immunophenotype: CD11c(+), CD25(+), CD103(+), CD123(+)

Hairy Cell Leukemia Variant

  • Many similarities and overlap with SDRP SBCL

  • Polar cytoplasmic projections and central nuclei, each with distinct nucleolus

  • Anemia and thrombocytopenia more common than in SDRP SBCL

  • Higher degree of lymphocytosis than in SDRP SBCL

Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Splenic Diffuse Red Pulp Small B-cell Lymphoma

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