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{{Splenic marginal zone lymphoma}}
{{Splenic marginal zone lymphoma}}
{{CMG}}; {{AE}} {{AS}}
{{CMG}}; {{AE}}{{Affan}}, {{AS}}
==Overview==
==Overview==
'''Splenic marginal zone lymphoma''' (SMZL) is a [[lymphoma]] comprised of [[B-cells]] that replace the normal architecture of the [[white pulp]] of the [[spleen]]. Genes involved in the pathogenesis of splenic marginal zone lymphoma include [[immunoglobulin]] genes and CDK6 gene. On microscopic histopathological analysis, [[B-cells]], villous lymphocytes, and [[sinus]] invasion are characteristic findings of splenic marginal zone lymphoma. <ref name="who1">[http://www.iarc.fr/WHO-BlueBooks/BBwebsite/bb3.html] Jaffe E.S., Harris N.L., Stein H., Vardiman J.W. (eds): '''World Health Organization Classification of Tumors. Pathology and Genetics of Tumours of Haemopoietic and Lymphoid Tissues.''' IARC Press: Lyon 2001 </ref>There are no established causes for splenic marginal zone lymphoma. Splenic marginal zone lymphoma must be differentiated from other diseases such as  [[chronic lymphocytic leukemia]],  [[follicular lymphoma]], and [[mantle cell lymphoma]].<ref name=cancer.gov> Splenic marginal zone lymphoma. Surveillance, Epidemiology, and End Results Program. http://seer.cancer.gov/seertools/hemelymph/51f6cf57e3e27c3994bd5327/. Accessed on January 14, 2016</ref> The incidence of splenic marginal zone lymphoma increases with age; the median age at diagnosis is 50 years. Splenic marginal zone lymphoma affects men and women equally.<ref name="ber1">
'''Splenic marginal zone lymphoma''' ([[SMZL]]) is rare, indolent [[B-cell]] [[lymphoma]] that may arise from either pre germinal or germinal/post germinal center replacing the normal architecture of the [[white pulp]] of the [[spleen]]. [[Chromosomal aberrations]] and [[gene]] [[mutations]] involved in the pathogenesis of [[splenic marginal zone lymphoma]] include 7q32 deletion, gain of function 3q, 4q and [[NOTCH2]], [[TP53]], [[KLF2]] and [[immunoglobulin heavy chain gene]]. On microscopic [[histopathological]] analysis, [[micronodular]] lymphocytic infiltration of the [[white pulp]] along with biphasic distribution of neoplastic [[B-cells]] in the follicles of [[spleen]], mixed pattern of [[lymphocytic infiltration]] of the [[bone marrow]] and villous [[lymphocytes]] in peripheral blood, are the characteristic findings of [[splenic marginal zone lymphoma]] ([[SMZL]]). [[Hepatitis C]] viral antigen is also assumed to be involved in its causation. [[Splenic marginal zone lymphoma]] ([[SMZL]]) must be differentiated from other [[B-cell]] [[lymphomas]] such as  [[chronic lymphocytic leukemia]],  [[follicular lymphoma]], and [[mantle cell lymphoma]] and unclassifiable [[splenic lymphomas]] including hairy cell leukemia variant (HCL-v) and splenic diffuse red pulp small B-cell lymphoma (SDRPL). The incidence of [[splenic marginal zone lymphoma]] ([[SMZL]]) increases with age; the median age at diagnosis is 65-70 years. [[Splenic marginal zone lymphoma]] ([[SMZL]]) affects men and women equally. There are no established risk factors. According to the the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening. Low [[Hemoglobin]] levels, high [[lactate dehydrogenase]] levels, low blood serum [[albumin]] levels,  and  genetic mutations in [[NOTCH]]2 [[TP53]] genes are associated with poor prognosis. According to the Lugano classification, there are four stages of [[splenic marginal zone lymphoma]] ([[SMZL]]) based on the number of nodes and extranodal involvement. The most common symptoms of [[splenic marginal zone lymphoma]] include [[fever]], [[weight loss]], [[skin rash]], [[night sweats]], [[chest pain]], [[abdominal pain]], [[bone pain]], and painless swelling in the [[neck]], [[axilla]], [[groin]], [[thorax]], and [[abdomen]]. Common physical examination findings of [[splenic marginal zone lymphoma]] ([[SMZL]]) include [[fever]], [[rash]], [[ulcer]], [[splenomegaly]], [[chest tenderness]], abdomen tenderness, [[bone]] tenderness, [[Lymphadenopathy|peripheral lymphadenopathy]], and [[Lymphadenopathy|central lymphadenopathy]]. Laboratory tests for [[splenic marginal zone lymphoma]] ([[SMZL]]) include [[complete blood count]] (CBC), blood chemistry studies, [[cytogenetic analysis]], [[flow cytometry]], [[immunohistochemistry]], [[genetic testing]], [[FISH]], [[PCR]], and [[immunophenotyping]]. [[Lymph node]] or extranodal tissue( spleen, bone marrow) biopsy is diagnostic of splenic marginal zone lymphoma.[[splenomegaly]] and [[lymphadenopathy]] and other organs involvement may be seen on abdominal ultrasound, [[CT scan]], [[MRI]] and [[PET scan]] in patients with [[splenic marginal zone lymphoma]] ([[SMZL]]). Other diagnostic studies include [[laparoscopy]], [[laparotomy]]. The optimal therapy for [[splenic marginal zone lymphoma]] ([[SMZL]]) depends on the clinical presentation of the patient. Asymptomatic patients may be observed closely without any treatment. [[Splenomegaly]] related symptoms such as [[abdominal distension]], [[tenderness]], early [[satiety]], [[bloating]] and [[cytopenia]] due to [[hypersplenism]] may be managed with [[splenectomy]] but if [[bone marrow]] is involved it will persist even after [[surgery]]. '''[[Splenectomy]]''' was considered to be the first line treatment option but studies reported recently that '''[[rituximab]]''' alone or in combination with [[chemotherapy]] is equally effective if not better in terms of complete remission, progression free and overall survival and in addition there is no surgical risk. Studies have also shown that patients who relapsed while on treatment with [[rituximab]], responded well with retreatment. Patients with [[hepatitis C]] who developed [[splenic marginal zone lymphoma]] ([[SMZL]]) have shown tumor regression with [[antiviral]] therapy.
[http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=10706860&query_hl=7&itool=pubmed_ExternalLink]
 
Berger F, Felman P, Thieblemont C, Pradier T, Baseggio L, Bryon PA, Salles G, Callet-Bauchu E, Coiffier B. "Non-MALT marginal zone B-cell lymphomas: a description of clinical presentation and outcome in 124 patients." '''Blood'''. 2000 Mar 15;95(6):1950-6. PMID: 10706860</ref> There are no established risk factors for splenic marginal zone lymphoma. According to the the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for splenic marginal zone  lymphoma.<ref> Recommendations. U.S Preventive Services Task Force. http://www.uspreventiveservicestaskforce.org/BrowseRec/Search?s=SPLENIC+MARGINAL+ZONE+LYMPHOMA Accessed on December 23, 2015</ref> Low [[Hemoglobin]] levels, high [[lactate dehydrogenase]] levels, low blood serum [[albumin]] levels,  and  genetic mutations such as mutations in ''NOTCH2'' are associated with poor prognosis among patients with splenic marginal zone lymphoma. According to the Lugano classification, there are four stages of splenic marginal zone lymphoma based on the number of nodes and extranodal involvement. The most common symptoms of splenic marginal zone lymphoma include [[fever]], [[weight loss]], skin rash, [[night sweats]], chest pain, [[abdominal pain]], [[bone pain]], and painless swelling in the neck, axilla, groin, thorax, and abdomen. Common physical examination findings of splenic marginal zone lymphoma include [[fever]], [[rash]], [[ulcer]], [[splenomegaly]], chest tenderness, abdomen tenderness, bone tenderness, [[Lymphadenopathy|peripheral lymphadenopathy]], and [[Lymphadenopathy|central lymphadenopathy]].<ref name= seer>Splenic marginal zone lymphoma. Surveillance, Epidemiology, and End Results Program. http://seer.cancer.gov/seertools/hemelymph/51f6cf57e3e27c3994bd5327/ Accessed on December 22, 2015 </ref> Laboratory tests for splenic marginal zone lymphoma include [[complete blood count]] (CBC), blood chemistry studies, [[cytogenetic analysis]], [[flow cytometry]], [[immunohistochemistry]], [[genetic testing]], [[FISH]], [[PCR]], and [[immunophenotyping]]. Lymph node or extranodal tissue biopsy is diagnostic of splenic marginal zone lymphoma. CT scan may be helpful in the diagnosis of splenic marginal zone lymphoma. MRI may be helpful in the diagnosis of splenic marginal zone lymphoma. Abdomen ultrasound may be helpful in the diagnosis of splenic marginal zone lymphoma. Findings on ultrasound abdomen suggestive of splenic marginal zone lymphoma include [[splenomegaly]] and [[lymphadenopathy]]. [[PET]] scan may be helpful in the diagnosis of splenic marginal zone lymphoma. Other diagnostic studies for splenic marginal zone lymphoma include [[laparoscopy]], [[laparotomy]], [[bone marrow aspiration]], and [[bone marrow biopsy]].<ref name= seer > Splenic marginal zone lymphoma. Surveillance, Epidemiology, and End Results Program. http://seer.cancer.gov/seertools/hemelymph/51f6cf57e3e27c3994bd5327/ Accessed on December 22, 2015</ref> The predominant therapy for splenic marginal zone lymphoma is [[surgery]]. Adjunctive [[radiotherapy]], [[chemotherapy]], and [[biological therapy]] may be required. The optimal therapy for  splenic marginal zone lymphoma depends on the clinical presentation. The feasibility of surgery depends on the stage of splenic marginal zone lymphoma at diagnosis.  
==Historical Perspective==
The term [[splenic marginal zone lymphoma]] ([[SMZL]]) was used by C. Schmid in 1992 and is described as separate entity from [[marginal zone lymphoma]] in the World Health Organization classification of [[lymphoid neoplasms]] in 2001.  
==Pathophysiology==
==Pathophysiology==
Genes involved in the pathogenesis of splenic marginal zone lymphoma include [[immunoglobulin]] genes and CDK6 gene. On microscopic histopathological analysis, [[B-cells]], villous lymphocytes, and [[sinus]] invasion are characteristic findings of splenic marginal zone lymphoma. <ref name="who1">[http://www.iarc.fr/WHO-BlueBooks/BBwebsite/bb3.html] Jaffe E.S., Harris N.L., Stein H., Vardiman J.W. (eds): '''World Health Organization Classification of Tumors. Pathology and Genetics of Tumours of Haemopoietic and Lymphoid Tissues.''' IARC Press: Lyon 2001 </ref>
The exact pathogenesis of [[splenic marginal zone lymphoma]] ([[SMZL]]) is not clearly understood but according to some studies chronic immunologic stimulation and certain [[gene]] [[mutations]] are assumed to be involved. The common [[chromosomal]] aberrations and genetic mutations in [[splenic marginal zone lymphoma]] ([[SMZL]]) includes 7q32 deletion, gain of function [[mutation]] in 3q and  [[NOTCH2]], [[TP53]], [[KLF2]] [[gene]] [[mutations]]. These [[genes]] control certain [[cell regulation]] pathways that are involved in normal functioning of the cell. [[Hepatitis C]] viral antigen has also been assumed to be involved in its pathogenesis. [[Spleen]], [[bone marrow]], [[lymph nodes]], liver and [[blood]] may be infiltrated with the tumor and have certain distintive features. On microscopic histopathological analysis, [[B-cells]], villous [[lymphocytes]], and [[sinus]] invasion are characteristic findings of [[splenic marginal zone lymphoma]] ([[SMZL]]).
==Causes==
==Causes==
There are no established causes for splenic marginal zone lymphoma.
Some studies suggest an association between [[Hepatitis C]] and [[splenic marginal zone lymphoma]] ([[SMZL]]) and assume that it may have some role in its causation.  
==Differential Diagnosis==
==Differential Diagnosis==
Splenic marginal zone lymphoma must be differentiated from other diseases such as [[chronic lymphocytic leukemia]],  [[follicular lymphoma]], and [[mantle cell lymphoma]].<ref name=cancer.gov> Splenic marginal zone lymphoma. Surveillance, Epidemiology, and End Results Program. http://seer.cancer.gov/seertools/hemelymph/51f6cf57e3e27c3994bd5327/. Accessed on January 14, 2016</ref>
[[Splenic marginal zone lymphoma]] ([[SMZL]]) must be differentiated from other [[B-cell]] [[lymphomas]] such as [[chronic lymphocytic leukemia]],  [[follicular lymphoma]], [[mantle cell lymphoma]] and unclassifiable B-cell lymphomas including Hairy cell leukemia variant (HCL-v) and splenic diffuse red pulp small B-cell lymphoma (SDRPL) on the basis of cytogenetics, [[immunophenotyping]] and morphological as the treatment for these conditions varies.
==Epidemiology and demographics==
==Epidemiology and demographics==
The incidence of splenic marginal zone lymphoma increases with age; the median age at diagnosis is 50 years. Splenic marginal zone lymphoma affects men and women equally.<ref name="ber1">
[[Splenic marginal zone lymphoma]] ([[SMZL]]) constitutes less than 1% of all [[non-Hodgkin's lymphomas]]. Its incidence increases with age. It is found to be more common in caucasians. [[Splenic marginal zone lymphoma]] ([[SMZL]]) affects men and women equally.
[http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=10706860&query_hl=7&itool=pubmed_ExternalLink]
Berger F, Felman P, Thieblemont C, Pradier T, Baseggio L, Bryon PA, Salles G, Callet-Bauchu E, Coiffier B. "Non-MALT marginal zone B-cell lymphomas: a description of clinical presentation and outcome in 124 patients." '''Blood'''. 2000 Mar 15;95(6):1950-6. PMID: 10706860</ref>
==Risk Factors==
==Risk Factors==
There are no established risk factors for splenic marginal zone lymphoma.
There are no established risk factors for splenic marginal zone lymphoma.
==Screening==
==Screening==
According to the the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for splenic marginal zone  lymphoma.<ref> Recommendations. U.S Preventive Services Task Force. http://www.uspreventiveservicestaskforce.org/BrowseRec/Search?s=SPLENIC+MARGINAL+ZONE+LYMPHOMA Accessed on December 23, 2015</ref>
According to the the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for splenic marginal zone  lymphoma
==Prognosis==
==Natural History, Complications and Prognosis==
Low [[Hemoglobin]] levels, high [[lactate dehydrogenase]] levels, low blood serum [[albumin]] levels,  and  genetic mutations such as mutations in ''NOTCH2'' are associated with poor prognosis among patients with splenic marginal zone lymphoma.
Splenic marginal zone lymphoma ([[SMZL]]) is a rare, slow growing B-cell lymphoma that is mostly [[asymptomatic]] at the time of diagnosis. It is commonly diagnosed at an old age. Patients typically have [[splenomegaly]], [[lymphocytosis]] or [[cytopenias]]. [[Bone marrow]] is frequently involved but [[lymphadenopathy]] and [[live]]r involvement is rare.There are [[automimmune]] conditions that may develop in this conditions such [[autoimmune hemolytic anemia]], [[idiopathic thrombocytopenic purpura]], [[angioedema]] and [[von-willebrand disease]]. It may transform into [[diffuse large B-cell lymphoma]]. The prognosis is generally good. Several factors including [[lymphadenopathy]], [[non-hematopoietic]] site involvement, histologic transformation affects the prognosis. Low [[Hemoglobin]] levels, high [[lactate dehydrogenase]] levels, low blood serum [[albumin]] levels,  and  [[genetic]] [[mutations]] such as mutations in [[NOTCH2]], [[TP53]], [[KLF2]] are associated with poor prognosis among patients with [[splenic marginal zone lymphoma]].
==Staging==
 
According to the Lugano classification, there are four stages of splenic marginal zone lymphoma based on the number of nodes and extranodal involvement.
==Diagnosis==
==Symptoms==
===Diagnostic Study of Choice===
The most common symptoms of splenic marginal zone lymphoma include [[fever]], [[weight loss]], skin rash, [[night sweats]], chest pain, [[abdominal pain]], [[bone pain]], and painless swelling in the neck, axilla, groin, thorax, and abdomen.
[[Histological]] examination of the spleen is considered as a gold standard for the diagnosis of splenic marginal zone lymphoma ([[SMZL]]). But as [[splenectomy]] is not as frequently performed as it was other diagnostic options are sought which includes [[histological]] analysis and [[immunohistochemistry]] of the [[bone marrow]] [[biopsy]] and [[peripheral blood]]. Cytogenetic analysis is also helpful in making the diagnosis.
==Physical Examination==
===Staging===
Common physical examination findings of splenic marginal zone lymphoma include [[fever]], [[rash]], [[ulcer]], [[splenomegaly]], chest tenderness, abdomen tenderness, bone tenderness, [[Lymphadenopathy|peripheral lymphadenopathy]], and [[Lymphadenopathy|central lymphadenopathy]].<ref name= seer>Splenic marginal zone lymphoma. Surveillance, Epidemiology, and End Results Program. http://seer.cancer.gov/seertools/hemelymph/51f6cf57e3e27c3994bd5327/ Accessed on December 22, 2015 </ref>
According to the Lugano classification, there are four stages of splenic marginal zone lymphoma ([[SMZL]]) based on the number of nodes and extranodal involvement.
==Laboratory tests==
 
Laboratory tests for splenic marginal zone lymphoma include [[complete blood count]] (CBC), blood chemistry studies, [[cytogenetic analysis]], [[flow cytometry]], [[immunohistochemistry]], [[genetic testing]], [[FISH]], [[PCR]], and [[immunophenotyping]].
===History and Symptoms===
==Biopsy==
The most common symptoms of splenic marginal zone lymphoma ([[SMZL]]) include [[fever]], [[weight loss]], skin rash, [[night sweats]], chest pain, [[abdominal pain]], [[bone pain]], and painless swelling in the neck, [[axilla]], [[groin]], [[thorax]], and [[abdomen]].
Lymph node or extranodal tissue biopsy is diagnostic of splenic marginal zone lymphoma.
 
==CT==
===Physical Examination===
CT scan may be helpful in the diagnosis of splenic marginal zone lymphoma.
Common physical examination findings of splenic marginal zone lymphoma ([[SMZL]]) include [[fever]], [[rash]], [[ulcer]], [[splenomegaly]], chest tenderness, abdomen tenderness, bone tenderness, [[Lymphadenopathy|peripheral lymphadenopathy]], and [[Lymphadenopathy|central lymphadenopathy]].
==MRI==
 
MRI may be helpful in the diagnosis of splenic marginal zone lymphoma.
===Laboratory tests===
==Ultrasound==
Laboratory tests for splenic marginal zone lymphoma ([[SMZL]]) include [[complete blood count]] (CBC), blood chemistry studies, [[immunohistochemistry]], [[genetic testing]], [[flow cytometry]], [[FISH]], [[PCR]], and [[immunophenotyping]].
Abdomen ultrasound may be helpful in the diagnosis of splenic marginal zone lymphoma. Findings on ultrasound abdomen suggestive of splenic marginal zone lymphoma include [[splenomegaly]] and [[lymphadenopathy]].
 
==Other Imaging Studies==
===Biopsy===
[[PET]] scan may be helpful in the diagnosis of splenic marginal zone lymphoma.
Lymph node or extranodal tissue biopsy is diagnostic of splenic marginal zone lymphoma ([[SMZL]]).
==Other Diagnostic Studies==
===CT===
Other diagnostic studies for splenic marginal zone lymphoma include [[laparoscopy]], [[laparotomy]], [[bone marrow aspiration]], and [[bone marrow biopsy]].<ref name= seer > Splenic marginal zone lymphoma. Surveillance, Epidemiology, and End Results Program. http://seer.cancer.gov/seertools/hemelymph/51f6cf57e3e27c3994bd5327/ Accessed on December 22, 2015</ref>
[[CT scan]] may be helpful in the diagnosis and estimating the extent of tumor spread in splenic marginal zone lymphoma ([[SMZL]]).
==Medical Therapy==
===MRI===
The predominant therapy for splenic marginal zone lymphoma is [[surgery]]. Adjunctive [[radiotherapy]], [[chemotherapy]], and [[biological therapy]] may be required. The optimal therapy for  splenic marginal zone lymphoma depends on the clinical presentation.
[[MRI]] may be helpful in the diagnosis of splenic marginal zone lymphoma ([[SMZL]]).
==Surgery==
The feasibility of surgery depends on the stage of splenic marginal zone lymphoma at diagnosis.  


==References==
===Ultrasound===
{{reflist|2}}
Abdomen ultrasound may be helpful in the diagnosis of splenic marginal zone lymphoma ([[SMZL]]). Findings on [[ultrasound]] [[abdomen]] suggestive of splenic marginal zone lymphoma ([[SMZL]]) include [[splenomegaly]] and [[lymphadenopathy]].


{{WH}}
===Other Imaging Studies===
{{WS}}
[[PET]] scan may be helpful in the diagnosis of splenic marginal zone lymphoma ([[SMZL]]).
===Other Diagnostic Studies===
Other diagnostic studies for splenic marginal zone lymphoma ([[SMZL]]) include [[laparoscopy]] and [[laparotomy]].


[[Category:Disease]]
==Treatment==
===Medical Therapy===
There is no standardized treatment of splenic marginal zone lymphoma ([[SMZL]]) The optimal therapy depends on the clinical presentation. [[Asymptomatic]] patients may only be observed routinely without any treatment as it is an indolent tumor. [[Symptomatic]] patients may treated with either [[surgery]], [[immunotherapy]], [[chemotherapy]], immunochemotherapy or [[antiviral]] drugs. Both [[surgery]] and [[immunotherapy]] are equally effective but recently [[immunotherapy]] is considered as a better treatment option as there is no risk of complications that are associated with [[surgery]].
===Surgery===
[[Splenectomy]] was considered to be the 1st line treatment option for splenic marginal zone lymphoma ([[SMZL]]) but recent studies have shown that [[rituximab]] is equally effective if not better treatment option in terms of overall survival. [[Splenectomy]] is still performed but mainly in patients with [[splenomegaly]] without [[lymphadenopathy]] having low surgical risk or in those who are refractory to [[rituximab]] therapy.

Latest revision as of 16:07, 1 February 2019

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Muhammad Affan M.D.[2], Sowminya Arikapudi, M.B,B.S. [3]

Overview

Splenic marginal zone lymphoma (SMZL) is rare, indolent B-cell lymphoma that may arise from either pre germinal or germinal/post germinal center replacing the normal architecture of the white pulp of the spleen. Chromosomal aberrations and gene mutations involved in the pathogenesis of splenic marginal zone lymphoma include 7q32 deletion, gain of function 3q, 4q and NOTCH2, TP53, KLF2 and immunoglobulin heavy chain gene. On microscopic histopathological analysis, micronodular lymphocytic infiltration of the white pulp along with biphasic distribution of neoplastic B-cells in the follicles of spleen, mixed pattern of lymphocytic infiltration of the bone marrow and villous lymphocytes in peripheral blood, are the characteristic findings of splenic marginal zone lymphoma (SMZL). Hepatitis C viral antigen is also assumed to be involved in its causation. Splenic marginal zone lymphoma (SMZL) must be differentiated from other B-cell lymphomas such as chronic lymphocytic leukemia, follicular lymphoma, and mantle cell lymphoma and unclassifiable splenic lymphomas including hairy cell leukemia variant (HCL-v) and splenic diffuse red pulp small B-cell lymphoma (SDRPL). The incidence of splenic marginal zone lymphoma (SMZL) increases with age; the median age at diagnosis is 65-70 years. Splenic marginal zone lymphoma (SMZL) affects men and women equally. There are no established risk factors. According to the the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening. Low Hemoglobin levels, high lactate dehydrogenase levels, low blood serum albumin levels, and genetic mutations in NOTCH2 TP53 genes are associated with poor prognosis. According to the Lugano classification, there are four stages of splenic marginal zone lymphoma (SMZL) based on the number of nodes and extranodal involvement. The most common symptoms of splenic marginal zone lymphoma include fever, weight loss, skin rash, night sweats, chest pain, abdominal pain, bone pain, and painless swelling in the neck, axilla, groin, thorax, and abdomen. Common physical examination findings of splenic marginal zone lymphoma (SMZL) include fever, rash, ulcer, splenomegaly, chest tenderness, abdomen tenderness, bone tenderness, peripheral lymphadenopathy, and central lymphadenopathy. Laboratory tests for splenic marginal zone lymphoma (SMZL) include complete blood count (CBC), blood chemistry studies, cytogenetic analysis, flow cytometry, immunohistochemistry, genetic testing, FISH, PCR, and immunophenotyping. Lymph node or extranodal tissue( spleen, bone marrow) biopsy is diagnostic of splenic marginal zone lymphoma.splenomegaly and lymphadenopathy and other organs involvement may be seen on abdominal ultrasound, CT scan, MRI and PET scan in patients with splenic marginal zone lymphoma (SMZL). Other diagnostic studies include laparoscopy, laparotomy. The optimal therapy for splenic marginal zone lymphoma (SMZL) depends on the clinical presentation of the patient. Asymptomatic patients may be observed closely without any treatment. Splenomegaly related symptoms such as abdominal distension, tenderness, early satiety, bloating and cytopenia due to hypersplenism may be managed with splenectomy but if bone marrow is involved it will persist even after surgery. Splenectomy was considered to be the first line treatment option but studies reported recently that rituximab alone or in combination with chemotherapy is equally effective if not better in terms of complete remission, progression free and overall survival and in addition there is no surgical risk. Studies have also shown that patients who relapsed while on treatment with rituximab, responded well with retreatment. Patients with hepatitis C who developed splenic marginal zone lymphoma (SMZL) have shown tumor regression with antiviral therapy.

Historical Perspective

The term splenic marginal zone lymphoma (SMZL) was used by C. Schmid in 1992 and is described as separate entity from marginal zone lymphoma in the World Health Organization classification of lymphoid neoplasms in 2001.

Pathophysiology

The exact pathogenesis of splenic marginal zone lymphoma (SMZL) is not clearly understood but according to some studies chronic immunologic stimulation and certain gene mutations are assumed to be involved. The common chromosomal aberrations and genetic mutations in splenic marginal zone lymphoma (SMZL) includes 7q32 deletion, gain of function mutation in 3q and NOTCH2, TP53, KLF2 gene mutations. These genes control certain cell regulation pathways that are involved in normal functioning of the cell. Hepatitis C viral antigen has also been assumed to be involved in its pathogenesis. Spleen, bone marrow, lymph nodes, liver and blood may be infiltrated with the tumor and have certain distintive features. On microscopic histopathological analysis, B-cells, villous lymphocytes, and sinus invasion are characteristic findings of splenic marginal zone lymphoma (SMZL).

Causes

Some studies suggest an association between Hepatitis C and splenic marginal zone lymphoma (SMZL) and assume that it may have some role in its causation.

Differential Diagnosis

Splenic marginal zone lymphoma (SMZL) must be differentiated from other B-cell lymphomas such as chronic lymphocytic leukemia, follicular lymphoma, mantle cell lymphoma and unclassifiable B-cell lymphomas including Hairy cell leukemia variant (HCL-v) and splenic diffuse red pulp small B-cell lymphoma (SDRPL) on the basis of cytogenetics, immunophenotyping and morphological as the treatment for these conditions varies.

Epidemiology and demographics

Splenic marginal zone lymphoma (SMZL) constitutes less than 1% of all non-Hodgkin's lymphomas. Its incidence increases with age. It is found to be more common in caucasians. Splenic marginal zone lymphoma (SMZL) affects men and women equally.

Risk Factors

There are no established risk factors for splenic marginal zone lymphoma.

Screening

According to the the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for splenic marginal zone lymphoma

Natural History, Complications and Prognosis

Splenic marginal zone lymphoma (SMZL) is a rare, slow growing B-cell lymphoma that is mostly asymptomatic at the time of diagnosis. It is commonly diagnosed at an old age. Patients typically have splenomegaly, lymphocytosis or cytopenias. Bone marrow is frequently involved but lymphadenopathy and liver involvement is rare.There are automimmune conditions that may develop in this conditions such autoimmune hemolytic anemia, idiopathic thrombocytopenic purpura, angioedema and von-willebrand disease. It may transform into diffuse large B-cell lymphoma. The prognosis is generally good. Several factors including lymphadenopathy, non-hematopoietic site involvement, histologic transformation affects the prognosis. Low Hemoglobin levels, high lactate dehydrogenase levels, low blood serum albumin levels, and genetic mutations such as mutations in NOTCH2, TP53, KLF2 are associated with poor prognosis among patients with splenic marginal zone lymphoma.

Diagnosis

Diagnostic Study of Choice

Histological examination of the spleen is considered as a gold standard for the diagnosis of splenic marginal zone lymphoma (SMZL). But as splenectomy is not as frequently performed as it was other diagnostic options are sought which includes histological analysis and immunohistochemistry of the bone marrow biopsy and peripheral blood. Cytogenetic analysis is also helpful in making the diagnosis.

Staging

According to the Lugano classification, there are four stages of splenic marginal zone lymphoma (SMZL) based on the number of nodes and extranodal involvement.

History and Symptoms

The most common symptoms of splenic marginal zone lymphoma (SMZL) include fever, weight loss, skin rash, night sweats, chest pain, abdominal pain, bone pain, and painless swelling in the neck, axilla, groin, thorax, and abdomen.

Physical Examination

Common physical examination findings of splenic marginal zone lymphoma (SMZL) include fever, rash, ulcer, splenomegaly, chest tenderness, abdomen tenderness, bone tenderness, peripheral lymphadenopathy, and central lymphadenopathy.

Laboratory tests

Laboratory tests for splenic marginal zone lymphoma (SMZL) include complete blood count (CBC), blood chemistry studies, immunohistochemistry, genetic testing, flow cytometry, FISH, PCR, and immunophenotyping.

Biopsy

Lymph node or extranodal tissue biopsy is diagnostic of splenic marginal zone lymphoma (SMZL).

CT

CT scan may be helpful in the diagnosis and estimating the extent of tumor spread in splenic marginal zone lymphoma (SMZL).

MRI

MRI may be helpful in the diagnosis of splenic marginal zone lymphoma (SMZL).

Ultrasound

Abdomen ultrasound may be helpful in the diagnosis of splenic marginal zone lymphoma (SMZL). Findings on ultrasound abdomen suggestive of splenic marginal zone lymphoma (SMZL) include splenomegaly and lymphadenopathy.

Other Imaging Studies

PET scan may be helpful in the diagnosis of splenic marginal zone lymphoma (SMZL).

Other Diagnostic Studies

Other diagnostic studies for splenic marginal zone lymphoma (SMZL) include laparoscopy and laparotomy.

Treatment

Medical Therapy

There is no standardized treatment of splenic marginal zone lymphoma (SMZL) The optimal therapy depends on the clinical presentation. Asymptomatic patients may only be observed routinely without any treatment as it is an indolent tumor. Symptomatic patients may treated with either surgery, immunotherapy, chemotherapy, immunochemotherapy or antiviral drugs. Both surgery and immunotherapy are equally effective but recently immunotherapy is considered as a better treatment option as there is no risk of complications that are associated with surgery.

Surgery

Splenectomy was considered to be the 1st line treatment option for splenic marginal zone lymphoma (SMZL) but recent studies have shown that rituximab is equally effective if not better treatment option in terms of overall survival. Splenectomy is still performed but mainly in patients with splenomegaly without lymphadenopathy having low surgical risk or in those who are refractory to rituximab therapy.