Neoplastic Hematopathology Update 2018 Aggressive B-cell Lymphomas Raju K. Pillai City of Hope National Medical Center
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Outline New entities and changes in WHO 2016 classification Double Hit Lymphoma and High grade B-cell lymphoma, NOS Prognostic and predictive factors in DLBCL EBV positive diffuse large B-cell lymphoma Primary mediastinal large B-cell lymphoma and related lesions Insights from genomic studies
WHO 2016 Classification Large B-cell Lymphomas Diffuse large B-cell lymphoma (DLBCL), NOS Germinal center B-cell type* Activated B-cell type* EBV+ DLBCL, NOS* EBV+ mucocutaneous ulcer* HHV8+ DLBCL, NOS* Lymphomatoid granulomatosis Plasmablastic lymphoma 90% Burkitt lymphoma Burkitt-like lymphoma with 11q aberration* High-grade B-cell lymphoma, with MYC and BCL2 and/or BCL6 rearrangements* High-grade B-cell lymphoma, NOS* NEW ENTITIES IN 2016 WHO CLASSIFICATION Primary DLBCL of the central nervous system Primary cutaneous DLBCL, leg type Intravascular large B-cell lymphoma Primary effusion lymphoma DLBCL associated with chronic inflammation T-cell/histiocyte-rich large B-cell lymphoma ALK+ large B-cell lymphoma Large B-cell lymphoma with IRF4 rearrangement* Primary mediastinal (thymic) large B-cell lymphoma B-cell lymphoma, unclassifiable, intermediate between DLBCL and CHL
Prognostic and Predictive factors in DLBCL 5 year PFS and OS with R-CHOP is 60% and 65% respectively Very high genetic and clinical heterogeneity 2 molecular subgroups defined by gene expression profiling ABC and GCB Alizadeh, Nature 2000
Cell of Origin in DLBCL
ABC and GCB subtypes Drive Different Pathways Differences in gene expression, chromosomal alterations, mutations and pathways affected ABC GCB BCL2 translocation 5% 40% BCL6 / 3q27 GAIN 45% 15% EZH2, GNA13, TNFRSF14 Rare 25% CD79B, MYD88 25% -30% Rare Pathways NF-kappaB PI3/AKT, JAK/STAT Survival, PFS, 5 yrs 40-50% 70-80%
Prognostic and Predictive factors in DLBCL Benefit from certain drugs is preferentially seen in the ABC subtype ( bortezomib, lenalidomide and Ibrutinib with R-CHOP) Determination of cell of origin subtype is required in the WHO 2016 classification Methods: IHC: State algorithm used (Hans, Choi, Tally) Gene expression profiling
Hans Algorithm for Cell of Origin
Other Methods to Determine Cell of Origin Concordance with gene expression profiling Hans 86% Tally 93% Choi 87% Meyer et al, JCO 2011
Gene Expression Profiling with Nanostring Technology Single molecule barcoding, FFPE compatible Up to 800X multiplex
Nanostring Technology
Lymph2Cx Assay Geneexpression profiling from 20 genes 8 ABC 7 GCB 5 controls 2% mis-assignment, 5% unclassified Scott DW 2015
Mutation Landscape and Networks in DLBCL Courtesy Sandeep Dave, Duke Cancer center. Reddy et al. Cell 2017: 171
Mutation Landscape and Networks in DLBCL More comprehensive risk stratification Choice of targeted therapy Genomic risk model can be applied clinically using existing assays, through the measurement of cell of origin, BCL2 and MYC expression, and targeted sequencing of a panel of DLBCL driver genes
WHO 2016 Classification Large B-cell Lymphomas Burkitt lymphoma Burkitt-like lymphoma with 11q aberration* High-grade B-cell lymphoma, with MYC and BCL2 and/or BCL6 rearrangements* High-grade B-cell lymphoma, NOS*
Diffuse proliferation of small to medium-sized monomorphous cells. Starry-sky pattern Slight nuclear pleomorphism, nuclear membrane irregularities, or nucleolar prominence is acceptable, particularly in immunodeficiency- associated cases, provided other key immunophenotypic and genetic criteria are met. Burkitt Lymphoma
Burkitt Lymphoma Centroblast Phenotype: CD20, CD10, BCL6 strongly positive BCL2-negative (maybe weak +) Ki-67 > 95% Genetics: MYC translocation > 95% of cases Usually IGH or IGL partners Absence of BCL2 or BCL6 rearrangement Non-complex karyotype Ki67 MYC
Differential Diagnosis Burkitt lymphoma Burkitt-like lymphoma with 11q aberration* High-grade B-cell lymphoma, with MYC and BCL2 and/or BCL6 rearrangements (Double Hit / Triple Hit lymphoma) High-grade B-cell lymphoma, NOS Diffuse large B-cell lymphoma
Important to Distinguish Burkitt Lymphoma Distinguishing Burkitt lymphoma from other aggressive B-cell lymphomas is important for therapeutic decisions and prognosis Undertreatment of BL leads to markedly inferior survival in a curable disease Overtreatment - BL therapy in misdiagnosed DLBCL leads to unnecessary toxicity No single parameter - morphology, phenotype or genetics can be used as a gold standard for diagnosis
Reconsider a Diagnosis of Burkitt Lymphoma High degree of morphologic variability in terms of nuclear size, nuclear irregularity, or nucleolar prominence Strong BCL2 expression Ki-67 less than 95% Positivity for MUM 1/IRF4, or negativity for BCL6 or CD10 Presence of BCL2 or BCL6 rearrangement in addition to MYC Older age at diagnosis in absence of immunosuppression or a predominantly leukemic presentation.
Is MYC Translocation specific to Burkitt lymphoma? BURKITT 90-100% PLASMABLASTIC LYMPHOMA 50% TRANSFORMED MYELOMAS 55% DLBCL, NOS 10-15% DOUBLE HIT LYMPHOMA 100% HIGH GRADE B, NOS 30-50% FL, CLL, MCL, B-ALL RARE
Are there MYC translocation negative Burkitt lymphomas? Morphology similar to Burkitt lymphoma but more pleomorphic More in immunodeficient patients Negative for MYC translocation Proximal gains and distal losses of 11q Gene expression profile similar to BL but with decreased MYC RNA and protein Clinical course similar to BL Burkitt-Like Lymphoma with 11q Aberrations (provisional category)
Molecular Pathogenesis of Burkitt Lymphoma Schmitz R, Nature 2012; Campo E. Nat Genet. 2012; ID3 55% TCF3 20% CCND3 38% MYC 70% TP53 50%
High Grade B-cell Lymphoma Revised definition in WHO 2016 Aggressive mature B-cell lymphomas with features intermediate between DLBCL and BL 2 categories: Double hit / triple hit lymphoma: High-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements High-grade B-cell lymphoma, NOS
Morphology of MYC/BCL2 or BCL6 Double Hit Lymphoma BL/DLBCL type starry sky pattern, but greater nuclear size variation, nuclear irregularity or nucleolar prominence than acceptable for BL Blastoid type - small cells with dispersed chromatin and absent / inconspicuous nucleoli DLBCL type - large cells resembling typical centroblasts or immunoblasts with high degree of nuclear size variability (50%)
Exclusion Criteria for Double Hit Lymphoma May arise from antecedent follicular lymphoma in half of MYC/BCL2 double hit lymphomas Excludes follicular lymphoma with MYC and BCL2 rearrangements, blastoid mantle and B-lymphoblastic leukemia Copy number alterations or somatic mutations of MYC and BCL2 do not qualify MYC and BCL2 protein expression do not correlate with DHL / THL but are useful for screening cases for FISH studies Ki-67 index does not correlate with DHL / THL (30-100%)
Overlap of High Grade B-cell lymphoma, NOS with BL Medium sized or slightly larger cells Variation in cell, nuclear and nucleolar size Higher proportion of cases expressing BCL2 Upto 20% of BL show weak expression of BCL2 Lack of CD10 expression Rare BL cases can be CD10 negative <90% Ki-67 expression One third of cases with the molecular signature of BL has <95% Ki-67 MYC translocation with Non-IgH/IgL partners Upto 10% are negative for MYC translocation Complex karyotype (>6 Abnormalities by SNP Array)
Diagnostic Approach to Aggressive B-cell Lymphomas Blastoid BL DLBCL/BL DLBCL MYC-R+ DHL / THL B-LBL BL HGBL-NOS DHL / THL DLBCL-NOS Exclude B-ALL, FL, Blastoid MCL, Plasmablastic Lymphoma
WHO 2016 Classification Large B-cell Lymphomas 90% EBV+ DLBCL, NOS* EBV+ mucocutaneous ulcer* HHV8+ DLBCL, NOS* Lymphomatoid granulomatosis Plasmablastic lymphoma
EBV positive large B-cell lymphomas Can occur in younger immunocompetent patients Morphologic spectrum: T cell / Histiocyte rich large B-cell like Classical Hodgkin like DLBCL Nodal disease, 11% had extracellular involvement Adverse prognosis only in older patients Immune modulation tolerogenic microenvironment Nicolae A et al. Blood (2015) 126:863
Mucocutaneous Ulcer Occurs in older adults with immune senescence, or with iatrogenic immunosuppression Cutaneous or mucosal Superficial ulcer with a marked reactive lymphoid infiltrate at the base. EBV positive in all cases Should be differentiated from EBV-positive large B-cell lymphoma Lesions resolve with decreased immunosuppression with or without rituximab. None of these patients are reported to have EBV DNA in their blood
WHO 2016 Classification Large B-cell Lymphomas Primary mediastinal (thymic) large B-cell lymphoma B-cell lymphoma, unclassifiable, intermediate between DLBCL and CHL
Case 2 21 year-old male with a history of progressive shortness of breath, 2 months duration Mediastinal mass biopsy
CD30 CD20
Primary mediastinal large B-cell lymphoma Young adults, more in females Bulky mediastinal mass; rarely outside Prominent sclerosis, compartmentalizing fibrosis Diffuse infiltrate of large or mediumsized lymphoma cells with abundant pale cytoplasm May resemble Reed-Sternberg like cells.
PMBL - Immunophenotype B-cell lineage antigens CD20, CD79a, PAX5, OCT2, BOB1 CD23 + in 70% CD30 + in 80% MAL + in 70% PDL1 and PDL2 in 70% Surface Ig negative in most cases BCL6 + in 60%, CD10 + in 25% EBV negative
PMBL Genetic Alterations CIITA rearrangements (53%) Decreased HLA Class II PDL1 / PDL2 Translocations and copy number alterations Inactivates T-cells Twa et al. Leuk Lymphoma. 2015;56:2239
PMBL Genetic Alterations Twa et al. Leuk Lymphoma. 2015;56:2239 CIITA rearrangements (53%) Decreased HLA Class II PDL1 / PDL2 Translocations and copy number alterations Inactivates T-cells NF-kappaB pathway activation JAK/STAT pathway activation
PMBL vs Mediastinal Gray zone Lymphoma Important to distinguish PMBL from BCLU- DLBCL/CHL B-cell lymphoma, unclassifiable-dlbcl/chl PMBL has good response to chemotherapy with high cure rates PMBL has more favorable survival than DLBCL
Case 3 52-year-old male Multiple enlarged retroperitoneal lymph nodes and left supraclavicular lymphadenopathy.
CD20 OCT2
CD30 CD15
BCLU DLBCL/CHL AKA Mediastinal gray-zone lymphoma (MGZL) Introduced as a provisional category in the 2008 WHO classification Most cases present as a mediastinal mass; male predominance BCLU DLBCL/CHL usually shows asynchrony between morphology and immunophenotype Morphology of Classical Hodgkin lymphoma, nodular sclerosis type Preserved B-cell program CD20, CD79a, BOB1 and OCT2, variable BCL6, and common loss of CD15 Morphology of DLBCL / PMBL In addition to B-cell marker expression, strong and homogeneous CD30 positivity and often CD15 positivity, or contain EBV.