ICD-O-2 Morphology

9710/3: Marginal zone lymphoma
9711/3: Monocytoid B-cell lymphoma
9715/3: Mucosal-associated lymphoid tissue lymphoma (MALT)
Effective 1992 - 2000

ICD-O-3 Morphology

9699/3: Marginal zone B-cell lymphoma, NOS
Effective 2001 and later


for cases diagnosed 1992 and later

Primary Site(s)

See Module 7
Note: Do not code primary site to spleen (C422). Most common sites of involvement: GI tract (stomach most common), salivary gland, lung, head and neck, ocular adnexa, skin, thyroid, and breast

Abstractor Notes

Do not code the primary site to spleen for this histology. If the primary site is spleen, code the histology to 9689/3 (splenic marginal zone lymphoma)

The majority of patients present with stage I or II disease. A minority have bone marrow (BM) involvement. The frequency of BM involvement is lower in gastric cases and higher in MALT lymphomas arising in the lung and ocular adnexa.

Multiple extranodal sites may be involved in up to 25% of extragastric cases at the time of presentation. MALT lymphomas may have involvement of multiple extranodal sites, particularly of paired organs (e.g. salivary glands) or organ systems (e.g. gastrointestinal tract, skin).

The differential diagnosis includes the history of reactive inflammatory process that typically precedes the lymphoma include:
1. Heliobacter pylori
2. Gastritis
3. Lymphoepithelial sialadenitis
4. Hashimoto thyroiditis
5. Other small B-cell lymphomas (follicular lymphoma, mantle cell lymphoma, small lymphocytic lymphoma).

The demonstration of immunoglobulin light chain restriction is important in the differential diagnosis.

There are two variants of MALT, both of which are coded to 9699/3:

1. Nodal marginal zone lymphoma (NMZL) usually presents with involvement of peripheral lymph nodes. Occasionally the bone marrow and peripheral blood are involved. NMZL is a primary B-cell neoplasm that morphologically resembles lymph nodes involved by marginal zone lymphoma of extranodal or splenic types, but without evidence of extranodal or splenic disease.

2. Pediatric nodal marginal zone lymphoma in the pediatric age group has distinct clinical and morphological characteristics. It presents predominantly in males and with localized (90% are Stage I) disease, mainly in the head and neck lymph nodes. Studies for clonal rearrangements of IGH@chain are necessary to help distinguish pediatric NMZL from reactive conditions. The prognosis for pediatric NMZL is excellent with very low relapse rates and long survival after conservative treatment.

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.


Not Applicable

Module Rule


Alternate Names

Bronchial-associated lymphoid tissue lymphoma
Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue
MALT lymphoma of the dura
Marginal zone B-cell lymphoma, NOS
Marginal zone lymphoma, NOS
Monocytoid B-cell lymphoma
Mucosal-associated lymphoid tissue lymphoma
Nodal marginal zone B-cell lymphoma
Nodal marginal zone lymphoma
Nodal MZL
Parafollicular B-cell lymphoma [OBS]
Pediatric nodal marginal zone lymphoma
Primary choroidal lymphoma (C693)
Skin-associated lymphoid tissue lymphoma


Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is an extranodal lymphoma composed of morphologically heterogeneous small B cells including marginal zone (centrocyte-like) cells, cells resembling monocytoid cells. There is plasmacytic differentiation in some case. The neoplastic cells reside int he marginal zones of reactive B-cell follicles and extend into the interfollicular region as well as into the follicles (follicular colonization).

Definitive Diagnostic Methods

Genetic testing
Histologic confirmation

Genetics Data

Immunoglobulin heavy and light chain genes rearranged
Translocation t(11;18)(q21;q21)
Translocation t(1;14)(p22;q32)
Translocation t(14;18)(q32;q21)
Trisomy 3, 18


BCL6- (no expression/negative)
CD5- (no expression/negative)
CD10- (no expression/negative)
CD11c+/- (positive/negative)
CD20+ (expression/positive)
CD23- (no expression/negative)
CD43+ (expression/positive)
CD43+/- (positive/negative)
CD79a+ (expression/positive)
Cyclin D1- (no expression/negative)
IgM+ (expression/positive)
Tumor cells may express IgA
Tumor cells may express IgG


Other therapy
Radiation therapy

Transformations from


Corresponding ICD-9 Codes

200.3 Marginal zone lymphoma

Corresponding ICD-10 Codes

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

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

C88.4 Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue [MALT lymphoma] (effective October 01, 2015)
C83.0 Small cell B-cell lymphoma (nodal marginal zone lymphoma) (effective October 01, 2015)

Signs and Symptoms

Drenching night sweats
Fever (for no known reason)
Pain in the chest, abdomen, or bones (for no known reason)
Painless swelling in the lymph nodes
Peripheral lymphadenopathy
Skin rash or itchy skin
Weight loss (for no known reason)

Diagnostic Exams

Blood chemistry studies
CT (CAT) scan
Cytogenetic analysis
Flow cytometry
Laparoscopy (rarely performed)
Laparotomy (rarely performed)
Lymph node biopsy
PET (positron emission tomography) scan

Progression and Transformation

Recurrences may occur after many years and may involve

Epidemiology and Mortality

Age: 61 years median age
Country: higher incidence in north-east Italy
Incidence: 7-8% of all B-cell lymphoma and up to 50% of primary gastric lymphomas
Sex: slight female predominance


Swerdlow SH, Campo E, Harris NL, Jaffe ES, Pileri SA, Stein H, Thiele J (Eds):
WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues (Revised 4th edition)
IARC: Lyon 2017
Section: Mature B-cell neoplasms
Pages: 259-265

International Classification of Diseases for Oncology, Third Edition, Second Revision. Geneva: World Health Organization, 2020.
Section: ICD-O-3.2 (2020) Morphological Codes

National Cancer Institute
Section: General Information About Adult Non-Hodgkin Lymphoma (NHL)