Name

Primary Mediastinal large B-cell lymphoma (PBML/PMBCL) (ICD-O-4: 96790/3)

ICD-O-3 Morphology

Effective 2001 and later

Reportable

for cases diagnosed 1978 and later

Primary Site(s)

C379 , C383
Do not assign this histology just because the mediastinum is involved. Only assign this histology when the diagnosis is stated as “primary mediastinal."

See abstractor notes.

Abstractor Notes

Primary Mediastinal large B-cell lymphoma (PBML/PMBCL) 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)

Code the primary site to C379 (thymus) or C383 (mediastinum) based on the physician's statement.

Primary mediastinal large B-cell lymphoma typically arises in the anterior-superior mediastinum (thymic niche) with variable extension to the lung, pleura, or pericardium. Regional lymph nodes are frequently involved, most commonly the supraclavicular lymph nodes.

Diagnostic Confirmation

Assign code 1 for histological confirmation WITH or WITHOUT positive immunophenotyping or genetics

Module Rule

None

Alternate Names

Mediastinal diffuse large cell lymphoma with sclerosis (MLCLS) (ICD-O-4: 96790/3)
Mediastinal large B-cell lymphoma (C383) (ICD-O-4: 96790/3)
Thymic large B-cell lymphoma (C379) (ICD-O-4: 96790/3)

Definition

Primary mediastinal large B-cell lymphoma (PMBCL) is a mature aggressive B-cell lymphoma of putative thymic B-cell origin, arising in the anterior mediastinum with distinctive clinical, immunophenotypic, and molecular features. (WHO 5th ed)

Definitive Diagnostic Methods

Cytogenetics
Genetic testing
Histologic confirmation
Immunohistochemistry
Immunophenotyping

Genetics Data

CIITA and PDL1/2 (9p24.1) SOCS1 JAK/STAT6 CIITA, B2M, TNFAIP3

Immunophenotyping

CD30, CD23, MAL, PDL1/2

Treatments

Chemotherapy
Radiation therapy

Transformations to

There are no known transformations

Transformations from

There are no known transformations

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

C83.8 Other types of diffuse non-Hodgkin lymphoma

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

C85.2_ Mediastinal (thymic) large B-cell lymphoma (effective October 01, 2015)
C85.2A Mediastinal (thymic) large B-cell lymphoma (effective October 01, 2024)

Signs and Symptoms

Drenching night sweats
Fatigue
Fever (for no known reason)
Localized anterosuperior mediastinal mass
Pain in the chest, abdomen, or bones (for no known reason)
Painless swelling in the lymph nodes
Skin rash or itchy skin
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

Progression and Transformation

None

Epidemiology and Mortality

Age: 35 years median age (occurs predominantly in young adults)
Incidence: 2-4% of non-Hodgkin lymphomas
Sex: M:F ratio: 1:2
Survival: beyond 2 years

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: Large B-cell lymphoma
Pages: Part B: 523-526

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 Aggressive B-Cell Non-Hodgkin Lymphoma Treatment. Bethesda, MD: National Cancer Institute. Updated <02/24/2025>. Available at: https://www.cancer.gov/types/lymphoma/hp/aggressive-b-cell-lymphoma-treatment-pdq. Accessed <03/20/2025>.
Section: Aggressive B-Cell Non-Hodgkin Lymphoma Treatment (PDQ®)–Health Professional Version
Pages: https://www.cancer.gov/types/lymphoma/hp/aggressive-b-cell-lymphoma-treatment-pdq
Glossary