splenic marginal zone lymphoma

The cell of origin is postulated to be a post-germinal center B-cell with an unknown degree of differentiation. SMZL is a form of cancer known to be associated with Hepatitis C virus infection.{{citation needed|date=December 2017}}

The relevant markers that define the immunophenotype for SMZL are shown in the adjacent table.

{{cite journal |vauthors=Isaacson PG, Matutes E, Burke M, Catovsky D |title=The histopathology of splenic lymphoma with villous lymphocytes |journal=Blood |volume=84 |issue=11 |pages=3828–34 |date=1 December 1994|pmid=7949139 |url=http://www.bloodjournal.org/cgi/pmidlookup?view=long&pmid=7949139 |doi=10.1182/blood.V84.11.3828.bloodjournal84113828 |doi-access=free }}

{{cite journal |vauthors=Matutes E, Morilla R, Owusu-Ankomah K, Houlihan A, Catovsky D |title=The immunophenotype of splenic lymphoma with villous lymphocytes and its relevance to the differential diagnosis with other B-cell disorders |journal=Blood |volume=83 |issue=6 |pages=1558–62 |date=15 March 1994|pmid=8123845 |url=http://www.bloodjournal.org/cgi/pmidlookup?view=long&pmid=8123845 |doi=10.1182/blood.V83.6.1558.1558 |doi-access=free }}

The lack of CD5 expression is helpful in the discrimination between SMZL and chronic lymphocytic leukemia/small lymphocytic lymphoma, and the lack of CD10 expression argues against follicular lymphoma. Mantle cell lymphoma is excluded due to the lack of CD5 and cyclin-D1 expression.

{{cite journal |author=Savilo E |title=Absence of cyclin D1 protein expression in splenic marginal zone lymphoma |journal=Mod. Pathol. |volume=11 |issue=7 |pages=601–6 |date=July 1998 |pmid=9688179 |name-list-style=vanc|author2=Campo E |author3=Mollejo M |display-authors=3 |last4=Pinyol |first4=M |last5=Piris |first5=MA |last6=Zukerberg |first6=LR |last7=Yang |first7=WI |last8=Koelliker |first8=DD |last9=Nguyen |first9=PL }}

Clonal rearrangements of the immunoglobulin genes (heavy and light chains) are frequently seen.{{cite journal |vauthors=Dunn-Walters DK, Boursier L, Spencer J, Isaacson PG |title=Analysis of immunoglobulin genes in splenic marginal zone lymphoma suggests ongoing mutation |journal=Hum. Pathol. |volume=29 |issue=6 |pages=585–93 |date=June 1998 |pmid=9635678 |doi=10.1016/S0046-8177(98)80007-5 }}

The deletion 7q21-32 is seen in 40% of SMZL patients, and translocations of the CDK6 gene located at 7q21 have also been reported.

{{cite journal |author=Corcoran MM |title=Dysregulation of cyclin dependent kinase 6 expression in splenic marginal zone lymphoma through chromosome 7q translocations |journal=Oncogene |volume=18 |issue=46 |pages=6271–7 |date=November 1999 |pmid=10597225 |doi=10.1038/sj.onc.1203033 |name-list-style=vanc|author2=Mould SJ |author3=Orchard JA |display-authors=3 |last4=Ibbotson |first4=R E |last5=Chapman |first5=R M |last6=Boright |first6=A P |last7=Platt |first7=C |last8=Tsui |first8=L-C |last9=Scherer |first9=S W|doi-access=free }}

Enlargement of the spleen is a requirement for the diagnosis of SMZL and is seen in nearly all people affected by SMZL (often without lymphadenopathy). Aside from the uniform involvement of the spleen, the bone marrow is frequently positive in patients with SMZL displaying a nodular pattern with morphology similar to what is observed in the splenic hilar lymph nodes.{{cite journal |vauthors=Franco V, Florena AM, Campesi G |title=Intrasinusoidal bone marrow infiltration: a possible hallmark of splenic lymphoma |journal=Histopathology |volume=29 |issue=6 |pages=571–5 |date=December 1996 |pmid=8971565 |doi=10.1046/j.1365-2559.1996.d01-536.x |s2cid=37364398 }} While nodal and extranodal involvement are rare, hilar lymph nodes adjacent to the spleen, if involved, show an effaced architecture without preservation of the marginal zone seen in the spleen.

Circulating lymphoma cells are sometimes present in peripheral blood, and they occasionally show short villi at the poles of cells and plasmacytoid differentiation.{{cite journal |vauthors=Melo JV, Hegde U, Parreira A, Thompson I, Lampert IA, Catovsky D |title=Splenic B cell lymphoma with circulating villous lymphocytes: differential diagnosis of B cell leukaemias with large spleens |journal=J. Clin. Pathol. |volume=40 |issue=6 |pages=642–51 |date=June 1987 |pmid=3497180 |pmc=1141055 |doi= 10.1136/jcp.40.6.642}}

Autoimmune thrombocytopenia and anemia are sometimes seen in patients with SMZL. A monoclonal paraprotein is detected in a third of patients without hypergammaglobulinemia or hyperviscosity.{{cite journal |author=Mollejo M |title=Splenic marginal zone lymphoma: a distinctive type of low-grade B-cell lymphoma. A clinicopathological study of 13 cases |journal=Am. J. Surg. Pathol. |volume=19 |issue=10 |pages=1146–57 |date=October 1995 |pmid=7573673 |doi= 10.1097/00000478-199510000-00005 |name-list-style=vanc|author2=Menárguez J |author3=Lloret E |display-authors=3 |last4=Sánchez |first4=A |last5=Campo |first5=E |last6=Algara |first6=P |last7=Cristóbal |first7=E |last8=Sánchez |first8=E |last9=Piris |first9=MA}}

Reactive germinal centers in splenic white pulp are replaced by small neoplastic lymphocytes that efface the mantle zone and ultimately blend in with the marginal zone with occasional larger neoplastic cells that resemble blasts.{{cite journal |vauthors=Jaffe ES, Costa J, Fauci AS, Cossman J, Tsokos M |title=Malignant lymphoma and erythrophagocytosis simulating malignant histiocytosis |journal=Am. J. Med. |volume=75 |issue=5 |pages=741–9 |date=November 1983 |pmid=6638043 |doi=10.1016/0002-9343(83)90402-3 }} The red pulp is always involved, with both nodules of larger neoplastic cells and sheets of the small neoplastic lymphocytes. Other features that may be seen include sinus invasion, epithelial histocytes, and plasmacytic differentiation of neoplastic cells.{{cn|date=March 2021}}

Three-quarters of patients survive five or more years; more than half of patients with SMZL survive more than a decade after diagnosis.{{cite journal|last=Arcaini|first=L.|year=2006|title=Splenic marginal zone lymphoma: a prognostic model for clinical use|journal=Blood|volume=107|issue=12|pages=4643–4649|issn=0006-4971|doi=10.1182/blood-2005-11-4659|pmid=16493005|url=https://iris.unimore.it/bitstream/11380/584206/1/Splenic%20marginal%20zone.......pdf|hdl=11380/584206|s2cid=13024127 }}

Patients who have a hemoglobin level of less than 12 g/dL, a lactate dehydrogenase level higher than normal, and/or a blood serum albumin levels of less than 3.5 g/dL are likely to have more an aggressive disease course and a shorter survival. However, even high-risk patients have even odds of living for five years after diagnosis.

Some genetic mutations, such as mutations in NOTCH2, are also correlated with shorter survival.{{cn|date=November 2022}}

Less than 1% of all lymphomas are splenic marginal zone lymphomas{{cite journal |vauthors=Armitage JO, Weisenburger DD |title=New approach to classifying non-Hodgkin's lymphomas: clinical features of the major histologic subtypes. Non-Hodgkin's Lymphoma Classification Project |journal=J. Clin. Oncol. |volume=16 |issue=8 |pages=2780–95 |date=August 1998 |pmid=9704731 |doi= 10.1200/JCO.1998.16.8.2780|url=http://www.jco.org/cgi/pmidlookup?view=long&pmid=9704731 |archive-url=https://archive.today/20130415043002/http://www.jco.org/cgi/pmidlookup?view=long&pmid=9704731 |url-status=dead |archive-date=2013-04-15 |url-access=subscription }} and it is postulated that SMZL may represent a large fraction of unclassifiable CD5- chronic lymphocytic leukemias. The typical patient is over the age of 50, and gender preference has been described.{{cite journal |author=Berger F |title=Non-MALT marginal zone B-cell lymphomas: a description of clinical presentation and outcome in 124 patients |journal=Blood |volume=95 |issue=6 |pages=1950–6 |date=March 2000 |pmid=10706860 |doi= 10.1182/blood.V95.6.1950|url=http://www.bloodjournal.org/cgi/pmidlookup?view=long&pmid=10706860 |name-list-style=vanc|author2=Felman P |author3=Thieblemont C |display-authors=3 |last4=Pradier |first4=T |last5=Baseggio |first5=L |last6=Bryon |first6=PA |last7=Salles |first7=G |last8=Callet-Bauchu |first8=E |last9=Coiffier |first9=B|url-access=subscription }}

Under older classification systems, the following names were used:

• List of hematologic conditions

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{{Medical resources

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| ICD9 = {{ICD9|200.3}}

| ICDO = {{ICDO|9689|3}}

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{{Hematological malignancy histology}}

{{DEFAULTSORT:Splenic Marginal Zone Lymphoma}}

Category:Lymphoma

Category:Hepatitis C virus-associated diseases