Lymph nodes have a similar morphology to MALT lymphomas with involvement of the marginal zones, but without extra nodal extension. 10-20% may transform to DLBCL. Bone marrow involvement is thought to occur in 30-60% of cases.
Category Archives: WHO Classification
Mediastinal Large B-Cell Lymphoma
Immunophenotypic Expression Pattern
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Marker
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Comment
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Negative
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Negative
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Negative
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Positive
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Positive (usually dim)
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Positive
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References
Parker, A., et. al. “Best Practice in Lymphoma Diagnosis and Reporting.” British Committee for Standards in Haematology, Royal College of Pathologists. April, 2010.
Plasmablastic Lymphoma
Immunophenotypic Expression Pattern
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Marker
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Comment
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Negative
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Weak/Negative
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Weak/Negative
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Negative
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Positive
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Variable
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Positive (Usually)
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Negative (Usually)
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Positive
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Rare + case
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References
Parker, A., et. al. “Best Practice in Lymphoma Diagnosis and Reporting.” British Committee for Standards in Haematology, Royal College of Pathologists. April, 2010.
T-Cell/Histiocyte-Rich Large B-Cell Lymphoma
T-Cell/Histiocyte-Rich Large B-Cell Lymphoma (TCHRLBCL) is characterized by spleen and bone marrow involvement. The morphology is of scattered large B-cells with a predominant background composed of T-cell and Histiocytes. The immunophenotype is variable, and an important differential diagnosis is with Hodgkin lymphoma.
Continue reading T-Cell/Histiocyte-Rich Large B-Cell Lymphoma
Primary Diffuse Large B-Cell Lymphoma of the CNS
Primary CNS Lymphoma represents lymphoma restricted to the cerebral or ocular parenchyma. It represents <1% of non-Hodgkin lymphomas, and 2-3% of brain tumors.
Continue reading Primary Diffuse Large B-Cell Lymphoma of the CNS
Primary Cutaneous DLBCL, Leg Type
Primary Cutaneous DLBCL, Leg Type is an uncommon cutaneous lymphoma (<5% of cutaneous lymphomas), but and important entity to differentiate due to its aggressive course. Unlike other cutaneous B-cell lymphomas, which are generally indolent and treated locally, primary cutaneous DLBCL, leg type behaves in a similar fashion to the systemic DLBCL (intermediate grade lymphoma) and is treated as such.
EBV Positive DLBCL of the Elderly
EBV+ DLBCL of the Elderly is an EBV expressing DLBCL in patients >50 years of age. Other lymphomas, which may express EBV, are excluded from this categorization. Most cases (70%) are extra nodal, while the remaining 30% have lymph node disease only.
ALK+ DLBCL
Rare variant of DLBCL. These cases often have loss of CD45, CD20, and CD79a expression, which may cause significant difficulty in diagnosis. Less than 40 cases have been reported in the medical literature. The term ALK-positive plasmablastic B-cell lymphoma may be the best term to remember to correlate with the IHC profile.
Intravascular Large B-Cell Lymphoma
The B-cell population is predominately confined to the lumen of blood vessels. The IHC immunophenotype may be similar to other DLBCLs and may have either a germinal center or non-germinal center immunophenotype. There are several important characteristics.
Immunophenotypic Expression Characteristics
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Marker
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Comment
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Negative (pan T-cell marker)
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Positive
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Co-expression may be seen on ~38% of the lymphoma cells.
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Co-expression may be seen on ~13% of the lymphoma cells.
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Variable. Usually positive in CD10 negative cases.
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References
Parker, A., et. al. “Best Practice in Lymphoma Diagnosis and Reporting.” British Committee for Standards in Haematology, Royal College of Pathologists. April, 2010.
Hematopathology. [edited by] Jaffe, ES. 1st. ed. Elsevier, Inc. © 2011.
Primary Effusion Lymphoma (PEL)
Primary Effusion Lymphoma (PEL) is a rare form of DLBCL associated with HIV infection.
Immunophenotypic Expression Pattern
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Marker
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Comment
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Negative
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Variable (often negative)
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Positive
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Positive
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Positive
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EBV (EBER)
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Positive (majority of cases)
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HHV-8
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Positive
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References
Parker, A., et. al. “Best Practice in Lymphoma Diagnosis and Reporting.” British Committee for Standards in Haematology, Royal College of Pathologists. April, 2010.