Quick Answers for Clinicians
A comprehensive patient history and physical exam, including a full skin examination and attention to node-bearing areas, the liver, and the spleen, are recommended for the initial workup of B-cell lymphomas. Initial laboratory testing should include a CBC with differential, lactate dehydrogenase (LDH) testing, a comprehensive metabolic panel, and uric acid testing. HIV and hepatitis C virus (HCV) testing may be added for at-risk patients. Additionally, a bone marrow biopsy with aspirate, a positron emission tomography (PET)/computed tomography (CT) scan and/or chest/abdominal/pelvic CT scan, and an echocardiogram may be informative and help guide treatment. Additional testing may be indicated based on the suspected classification. Molecular studies (B-cell clonality testing) may be helpful when the differential diagnosis includes a B-cell lymphoma versus a benign/reactive process (chronic inflammatory infiltrate).
Epstein-Barr virus (EBV) is associated with endemic and sporadic variants of Burkitt lymphoma (BL), a subset of diffuse large B-cell lymphomas (DLBCLs) in adults, a subset of posttransplant lymphoproliferative disorders, and some lymphomas in other immunocompromised patients. EBV testing is recommended in certain circumstances to guide diagnosis and proper treatment. Studies have demonstrated a strong association between hepatitis C virus (HCV) seropositivity and B-cell lymphomas, particularly DLBCL and marginal zone lymphoma. Testing is recommended in high-risk patients and in patients with splenic marginal zone lymphoma. HIV infection can lead to development of AIDS-related lymphomas. AIDS-related B-cell lymphomas include DLBCL, BL, primary central nervous system lymphoma, plasmablastic lymphoma, and primary effusion lymphoma. Human herpes virus 8 (HHV-8) is also associated with AIDS-related DLBCL and primary effusion lymphoma. Helicobacter pylori is associated with gastric extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT). Treatment with antibiotics can lead to tumor remission. Other bacteria less commonly associated with marginal zone lymphomas include Chlamydia psittaci, Campylobacter jejuni, and Borrelia burgdorferi.
The National Comprehensive Cancer Network (NCCN) B-Cell Lymphomas and Pediatric Aggressive Mature B-Cell Lymphomas guidelines provide detailed recommendations for specific B-cell lymphomas, including follicular lymphoma, marginal zone lymphomas, mantle cell lymphoma, diffuse large B-cell lymphoma (DLBCL), high-grade B-cell lymphomas, Burkitt lymphoma (BL), AIDS-related B-cell lymphomas, lymphoblastic lymphoma, posttransplant lymphoproliferative disorders, and Castleman disease, and also provide pediatric-specific guidelines for DLBCL and BL. The World Health Organization (WHO) and the European Organisation for Research and Treatment of Cancer (EORTC) have provided detailed information about the classification of various B-cell lymphomas.
Several published indices are available to assess prognosis for the various B-cell lymphomas. Proper classification is also important for appropriate treatment and prognostication, given that many of these lymphomas have different biologic behavior and outcomes. Prognostic indices for follicular lymphoma include the Follicular Lymphoma International Prognostic Index (FLIPI-1 and FLIPI-2). These prognostic indices include factors such as age, Ann Arbor stage, number of nodal sites involved, hemoglobin level, serum lactate dehydrogenase (LDH) level, size of largest involved lymph node, beta-2 microglobulin level, and bone marrow involvement to predict prognostic risk. A simpler index includes just baseline serum beta-2 microglobulin and LDH levels. Prognostic indices for diffuse large B-cell lymphoma (DLBCL) include the International Prognostic Index (IPI) and, for patients <60 years old, the revised IPI (R-IPI). The scores are based on stage of disease, serum LDH, Eastern Cooperative Oncology Group (ECOG) performance status, and the number of extranodal sites. A National Comprehensive Cancer Network (NCCN) IPI has been developed and stratifies patients into four risk groups using similar factors. Genetic risk factors should also be considered when determining prognostic risk.
The World Health Organization (WHO) has proposed a classification for B-cell lymphomas that integrates morphologic, immunophenotypic, genetic, and clinical features. The table below details a selected subset of the current WHO classifications for B-cell lymphomas, separated into clinical subtypes covered by the National Comprehensive Cancer Network (NCCN) B-cell lymphomas guidelines.
Marginal zone lymphomas
Mantle cell lymphoma
BL, Burkitt lymphoma; DLBCL, diffuse large B-cell lymphoma; MALT, mucosa-associated lymphoid tissue
Indications for Testing
The presentation of B-cell lymphomas varies widely among patients but may involve lymphadenopathy, fatigue, fever, recurrent infections, hepatosplenomegaly, eosinophilia, skin rash, leukemic manifestations, extranodal masses, or increased white blood cell (WBC) count. Phenotyping is necessary in most situations, and genetic studies may also be recommended. Specific diagnosis is important to determine proper medical management.
Excisional or incisional biopsy is typically required for initial evaluation. Fine needle aspiration (FNA) is generally not adequate for the initial diagnosis of lymphoma, and histologic grading cannot be performed on an FNA specimen. Core needle biopsies are not optimal but can sometimes be used. If the lymph node of interest is not accessible for excisional or incisional biopsy, a combination of FNA, core biopsy, and ancillary testing may be sufficient for diagnosis.
Phenotyping by flow cytometry can identify surface antigens on cells that can indicate the cell of origin and any immunophenotypic aberrancies. Flow cytometry is generally performed on peripheral blood, bone marrow, or tissue samples. The NCCN recommends investigation of the following markers in the initial evaluation of B-cell lymphomas: CD45, CD3, CD5, CD19, CD10, CD20, CD30, CD4, CD8, CD7, CD2, CD23, CD43, CD103, TDT, kappa, lambda, CD13, CD33, CD1a, cytoplasmic CD3, CD22, and myeloperoxidase. Investigation of additional markers may be useful to characterize specific classifications.
IHC staining may also be utilized for lymphoma phenotyping. The most commonly used stains offered at ARUP are cyclin D1, Pax-5, Ki-67, MUM1-IRF4, HHV8, EBV, ALK-1, CD3, CD5, CD10 (CALLA), CD19, CD20, CD21 (dendritic cell), CD22, CD23, CD25, CD30 (Ki-1), CD79A, CD138 (Syndecan-1), BCL-2, kappa and lambda light chains, and TdT. Other available stains include BOB-1, caspase-3, CD15, CD43, CD45, CD45RA-MT2, CD45RO, c-Myc, DBA.44, and Oct-2. For more information, refer to ARUP’s Immunohistochemistry Stain Offerings.
B-Cell Clonality Screening
Polyclonal immunoglobulin heavy chain (IgH) and immunoglobulin kappa light chain (IgK) gene rearrangements are characteristic of benign or reactive disease, whereas monoclonal rearrangements may indicate a lymphoma, although they are not entirely specific and can also be seen with infections, autoimmune diseases, and other sources of chronic inflammation. Conversely, a negative result does not exclude a lymphoma diagnosis. As such, B-cell clonality testing can be helpful but should be supported by cytologic and immunophenotypic testing to detect abnormal B-cell populations. This testing should be performed if morphology and immunophenotyping aren’t sufficient to determine the nature of the lymphoproliferative process. This testing also can be useful to monitor disease status after treatment.
Genetic tests to detect somatic mutations or structural abnormalities are often informative and, in some cases, are essential for accurate and precise diagnosis and prognostic assessment of B-cell lymphomas. In general, fluorescence in situ hybridization (FISH) and karyotyping are the best modalities for detecting translocations, whereas polymerase chain reaction (PCR) is useful for detecting and quantifying point mutations.
|High-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements, and BL||MYC, BCL2, BCL6|
|BL||MYC t(8;14), t(2;8), t(8;22)|
|DLBCL||BCL6, BCL2, IRF4/MUM1|
|Follicular lymphoma||BCL2 t(14;18)(q32;q21), IRF4/MUM1|
|Hairy cell leukemia||BRAF V600E|
|Mantle cell lymphoma||BCL1 (CCND1) t(11;14)(q13;q32)|
|Marginal zone lymphoma (nodal, MALT, splenic)||MYD88|
|MALT (gastric)||t(11;14), t(14;18), t(1;14), t(3;14), t(11:18)|
MYC, BCL2, and BCL6 Gene Rearrangements
B-cell lymphomas with two or three recurrent chromosomal breakpoint aberrations (rare) are referred to as double- or triple-hit lymphomas. These usually involve the MYC oncogene in association with BCL2 and/or BCL6 gene rearrangements and are classified by WHO as a “high-grade B-cell lymphoma, with MYC and BCL2 and/or BCL6 rearrangements.” It is important to identify these high-grade lymphomas because they tend to manifest aggressive behavior and respond poorly to traditional chemotherapy.
IRF4/DUSP22 Gene Rearrangement
Large B-cell lymphoma with IRF4 rearrangement is a recently described, low-grade entity that occurs most commonly in children and young adults. Strong IRF4/DUSP22 expression is usually seen with BCL6 and a high proliferation index. It is important to identify this disease because it is more aggressive than pediatric-type follicular lymphomas, but patients do well when treated. Large B-cell lymphomas with IRF4 rearrangement should also be distinguished from CD10-negative, IRF4/MUM1-positive follicular lymphoma, which is associated with DLBCLs in older adults.
ARUP Laboratory Tests
For additional IHC tests that may be useful in the diagnosis or differential diagnosis of B-cell lymphomas, refer to ARUP’s Immunohistochemistry Stain Offerings.
Capillary Electrophoresis/Polymerase Chain Reaction (PCR)
Fluorescence in situ Hybridization (FISH)
Fluorescence in situ Hybridization (FISH)
Polymerase Chain Reaction (PCR)
Real-Time Polymerase Chain Reaction
Swerdlow S, Campo E, Jaffe E, et al. WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues. 4th ed. International Agency for Research on Cancer; 2017.
Willemze R, Cerroni L, Kempf W, et al. The 2018 update of the WHO-EORTC classification for primary cutaneous lymphomas. Blood. 2019;133(16):1703-1714.
Evans PA, Pott Ch, Groenen PJ, et al. Significantly improved PCR-based clonality testing in B-cell malignancies by use of multiple immunoglobulin gene targets. Report of the BIOMED-2 Concerted Action BHM4-CT98-3936. Leukemia. 2007;21(2):207-214.
Swerdlow SH, Campo E, Pileri SA, et al. The 2016 revision of the World Health Organization classification of lymphoid neoplasms. Blood. 2016;127(20):2375-2390.