Lymphoma & related disorders
Mature B cell neoplasms
Small B cell lymphomas with a circulating component

Topic Completed: 1 February 2011

Minor changes: 19 November 2020

Copyright: 2001-2020,, Inc.

PubMed Search: small lymphocytic lymphoma

See also: CLL (chronic lymphocytic leukemia)

Nikhil Sangle, M.D.
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Cite this page: Sangle N. SLL. website. Accessed November 27th, 2020.
Definition / general
  • Common low grade B cell lymphoma with pseudofollicles composed of mature lymphocytes resembling soccer balls in peripheral blood; cells are CD5+, CD23+
Clinical features
  • Usually older patients (median age 60 years), 2/3 male, with disease in bone marrow, lymph nodes, spleen, liver
  • Often presents with leukemia, although patients may be asymptomatic
  • SLL may progress to blood (leukemic) involvement, but if so, there is usually less leukocytosis than cases with initial diagnosis of CLL
  • Almost all cases are B cell origin
  • Associated with hypogammaglobulinemia, monoclonal immunoglobulin spikes in some, infections; also autoantibodies to red blood cells and platelets causing hemolytic anemia and thrombocytopenia
  • Median survival 4 - 6 years; indolent unless it transforms
Prognostic factors
  • 17p deletions, 11q22-23 deletion, nonmutated immunoglobulin genes, aberrant expression of CD2, CD7, CD10, CD13, CD33 or CD34 (Am J Clin Pathol 2003;119:824)
Gross description
Microscopic (histologic) description
  • Effacement of nodal architecture by pale staining pseudofollicles or proliferation centers with ill defined borders, containing small round mature lymphocytes, prolymphocytes (larger than small lymphocytes, abundant basophilic cytoplasm, prominent nucleoli), paraimmunoblasts (larger cells with distinct nucleoli) and many smudge cells
  • Pseudofollicular centers are highlighted by decreasing light through the condenser at low power; cells have pale cytoplasm but resemble soccer balls or smudge cells on peripheral smear (cytoplasm is bubbly in mantle cell lymphoma); may have plasmacytoid features
  • May have marginal zone, perifollicular or interfollicular patterns, but these cases also have proliferation centers (Mod Pathol 2000;13:1161)
  • Interfollicular pattern: large, reactive germinal centers; resembles follicular lymphoma but germinal centers are BCL2 negative and tumor cells resemble SLL by morphology and immunostains (Am J Clin Path 2000;114:41)
  • Paraimmunoblastic variant: diffuse proliferation of paraimmunoblasts (normally just in pseudoproliferation centers); rare, < 30 reported cases; usually multiple lymphadenopathies and rapid disease progression; case report in 69 year old man (Hum Pathol 2002;33:1145); consider as mantle cell lymphoma if t(11;14)(q13;q32) is present; may also represent CD5+ diffuse large B cell lymphoma
  • Bone marrow: small focal aggregates of variable size with irregular, poorly circumscribed outlines; lymphocytes are well differentiated, small, round with minimal atypia; may have foci of transformation; rarely has granulomas (J Clin Pathol 2005;58:815)
  • Marrow infiltrative patterns are also described as diffuse (unmutated IgH genes, ZAP-70+, more aggressive), nodular (associated with IgH hypermutation, ZAP-70 negative) or mixed (variable mutation of IgH, variable ZAP-70, Hum Pathol 2006;37:1153)
Positive stains
Negative stains
Molecular / cytogenetics description
  • Trisomy 12 (30%, associated with atypical CLL and CD79b), deletion 13q14 (25 - 50%), deletion of 11q23 (worse prognosis, 10 - 20%)
Molecular / cytogenetics images

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IgH gene rearrangement

Differential diagnosis
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