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Pathology - Diffuse large B-cell lymphoma
A mature B-cell neoplasm characterized by big B-lymphoid cells exhibiting a diffuse growth pattern.
Epidemiology: Represents 25–30% of all non-Hodgkin lymphomas. • Primarily impacts senior individuals over the age of 60.
Aetiology • Often unidentified in numerous instances. • Significant correlation with immunodeficiency conditions, including HIV or post-transplant scenarios, where the lymphoma is induced by EBV, HHV-8, or both.
Genetics • Several genetic modifications have been identified in diffuse large B-cell lymphoma (DLBCL). The most prevalent translocation pertains to a segment of 3q that encodes the BCL6 gene.
Presentation: A rapidly enlarging mass that may be nodal (60%) or extranodal (40%). The gastrointestinal system is the most prevalent extranodal site, however almost any location may be involved.
Histopathology • Affected tissues are substituted by extensive sheets of giant atypical lymphoid cells, typically exceeding twice the size of a normal lymphocyte. • Apoptotic debris is commonly observed, and confluent regions of tumor necrosis may be present. Immunophenotype: Positive for B-cell markers PAX5, CD20, and CD79a. Cyclin D1 is absent. • Elevated proliferation index (typically 40–90% of cells).
Prognosis: Survival rates have significantly improved with the introduction of the anti-CD20 inhibitor, rituximab, achieving long-term survival rates of approximately 60–75%. Bone marrow involvement is typically linked to a bad prognosis.
A mature B-cell neoplasm characterized by big B-lymphoid cells exhibiting a diffuse growth pattern.
Epidemiology: Represents 25–30% of all non-Hodgkin lymphomas. • Primarily impacts senior individuals over the age of 60.
Aetiology • Often unidentified in numerous instances. • Significant correlation with immunodeficiency conditions, including HIV or post-transplant scenarios, where the lymphoma is induced by EBV, HHV-8, or both.
Genetics • Several genetic modifications have been identified in diffuse large B-cell lymphoma (DLBCL). The most prevalent translocation pertains to a segment of 3q that encodes the BCL6 gene.
Presentation: A rapidly enlarging mass that may be nodal (60%) or extranodal (40%). The gastrointestinal system is the most prevalent extranodal site, however almost any location may be involved.
Histopathology • Affected tissues are substituted by extensive sheets of giant atypical lymphoid cells, typically exceeding twice the size of a normal lymphocyte. • Apoptotic debris is commonly observed, and confluent regions of tumor necrosis may be present. Immunophenotype: Positive for B-cell markers PAX5, CD20, and CD79a. Cyclin D1 is absent. • Elevated proliferation index (typically 40–90% of cells).
Prognosis: Survival rates have significantly improved with the introduction of the anti-CD20 inhibitor, rituximab, achieving long-term survival rates of approximately 60–75%. Bone marrow involvement is typically linked to a bad prognosis.
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