Name

Splenic marginal zone lymphoma (SMZL)

ICD-O-3 Morphology

Effective 2001 and later

Reportable

for cases diagnosed 1978 and later

Primary Site(s)

C422
Primary site must be spleen (C422)

Abstractor Notes

Splenic marginal zone lymphoma (SMZL) is part of the Mature B-cell neoplasms lineage table in the WHO 5th edition of Hematolymphoid Tumors. (See Appendix B in the Hematopoietic Manual, Table B15)

SMZL typically presents with splenomegaly and involvement of the splenic hilar lymph nodes, bone marrow, and peripheral blood, and occasionally with microscopic hepatic involvement. Lymph nodes other than splenic hilar nodes are typically uninvolved.

Splenectomy may prolong remission.

Diagnostic Confirmation

This histology can be determined by positive histology (including peripheral blood) with or without genetics and/or immunophenotyping. Review the Definitive Diagnostic Methods, Immunophenotyping and Genetics Data sections below, and the instructions in the Hematopoietic Manual for further guidance on assigning Diagnostic confirmation.

Module Rule

None

Alternate Names

Splenic lymphoma with (circulating) villous lymphocytes
Splenic marginal zone lymphoma diffuse variant

Definition

Splenic marginal zone lymphoma (SMZL) is an indolent mature B-cell neoplasm primarily presenting in the spleen, preferentially involving the white pulp, often with villous lymphocytes in the peripheral blood, with or without involvement of splenic hilar lymph nodes. (WHO 5th edition)

Definitive Diagnostic Methods

Cytogenetics
Genetic testing
Histologic confirmation
Immunohistochemistry
Immunophenotyping

Genetics Data

Deletion 7q31-32 (sole molecular marker that associates SMZL)

Immunophenotyping

ANXA1- (no expression/negative)
BCL6- (no expression/negative)
CD20+ (expression/positive)
CD27+ (expression/positive)
CD38+ (expression/positive)
CD79a+ (expression/positive)
CD103- (no expression/negative)
Cyclin D1- (no expression/negative)
FMC7+ (expression/positive)
IgD+ (expression/positive)
IgM+ (expression/positive)
LEF1- (no expression/negative)
PAX5+ (expression/positive)
SOX 11- (no expression/negative)

Treatments

Chemotherapy
Immunotherapy
Surgery

Transformations from

None

Corresponding ICD-10 Codes (Cause of Death codes only)

C83.0 Non-Hodgkin lymphoma small cell (diffuse)

Corresponding ICD-10-CM Codes (U.S. only)

C83.0_ Small cell B-cell lymphoma (effective October 01, 2015)
C83.0A Small cell B-cell lymphoma, in remission (effective October 01, 2024)

Signs and Symptoms

Anemia
Drenching night sweats
Fatigue
Fever (for no known reason)
Pain in the chest, abdomen, or bones (for no known reason)
Painless swelling in the lymph nodes
Skin rashes or itchy skin
Splenomegaly
Thrombocytopenia (autoimmune)
Weight loss (for no known reason)

Diagnostic Exams

Blood chemistry studies
Bone marrow aspiration and biopsy
CT (CAT) scan
Cytogenetic analysis
Flow cytometry
Immunohistochemistry
Immunophenotyping
Laparoscopy (rarely performed)
Laparotomy (rarely performed)
Lymph node biopsy
PET (positron emission tomography) scan
Splenectomy

Progression and Transformation

Transformation to large B-cell lymphoma may occur

Epidemiology and Mortality

Age: mostly 50 years and older
Incidence: 2% of lymphoid neoplasms
Sex: no male or female predominance
Survival: long term survival for patients who have splenectomy

Sources

WHO Classification of Tumours Editorial Board. Haematolymphoid tumours. Lyon (France): International Agency for Research on Cancer; 2024. (WHO classification of tumours series, 5th ed.; vol. 11). https://publications.iarc.who.int/637.
Section: Splenic B-cell lymphomas and leukemias
Pages: Part B: 385-388

International Classification of Diseases for Oncology, 3rd edition (including revisions). Geneva: World Health Organization, 2001, 2011, 2020.
Section: ICD-O-3.2 (2020) Morphological Codes
Pages: http://www.iacr.com.fr/index.php?option=com_content&view=category&layout=blog&id=100&Itemid=577

PDQ® Adult Treatment Editorial Board. PDQ Indolent B-Cell Non-Hodgkin Lymphoma Treatment. Bethesda, MD: National Cancer Institute. Updated <02/18/2025>. Available at: https://www.cancer.gov/types/lymphoma/hp/indolent-b-cell-lymphoma-treatment-pdq. Accessed <03/04/2025>. [PMID: 37437080]
Section: Indolent B-Cell Non-Hodgkin Lymphoma Treatment (PDQ®)–Health Professional Version
Pages: https://www.cancer.gov/types/lymphoma/hp/adult-nhl-treatment-pdq
Glossary