Hyper-CVAD versus dose-adjusted EPOCH as initial treatment for adults with acute lymphoblastic leukemia.

OBJECTIVES: We recently performed a single-arm phase II trial of DA-EPOCH in adults with acute lymphoblastic leukemia (ALL). We sought to compare these results to those with standard Hyper-CVAD. METHODS: We created a retrospective matched cohort of patients who received Hyper-CVAD (n = 69) at our center and otherwise met eligibility criteria for the DA-EPOCH trial (n = 53). RESULTS: Our outcomes support the use of Hyper-CVAD over DA-EPOCH in Ph- disease for both overall survival (OS; HR 0.18, p = .004) and event-free survival (EFS; HR 0.51, p = .06). In contrast, outcomes were similar in Ph+ disease (OS HR 0.97, p = .96; EFS HR 0.65, p = .21). Rates of morphologic remission and measurable residual-disease negativity were similar between the regimens. Hyper-CVAD was associated with significantly more febrile neutropenia (OR 1.9, p = .03) and a greater incidence of Grade 4 or 5 adverse events (20% vs. 6%). Average transfusions per cycle of both red blood cells (p < .001) and platelets (p < .001) were five-fold higher with Hyper-CVAD. CONCLUSIONS: Our findings support continued use of Hyper-CVAD for Ph- ALL but suggest that DA-EPOCH may be a reasonable alternative for Ph+ ALL. These data also highlight a potential role for DA-EPOCH in resource-limited settings or when more intense therapy is not feasible.

The many faces of nodal and splenic marginal zone lymphomas. A report of the 2022 EA4HP/SH lymphoma workshop.

Session 3 of the lymphoma workshop of the XXI joint meeting of the European Association for Haematopathology and the Society for Hematopathology took place in Florence, Italy, on September 22, 2022. The topics of this session were splenic and nodal marginal zone lymphomas, transformation in marginal zone lymphomas, and pediatric nodal marginal zone lymphomas and their differential diagnosis as well as related entities. Forty-two cases in these categories were submitted to the workshop, including splenic lymphomas (marginal zone and diffuse red pulp lymphomas), transformed marginal zone lymphomas (splenic and nodal), nodal marginal zone lymphomas with increased TFH-cells, and pediatric nodal marginal zone lymphomas. The case review highlighted some of the principal problems in the diagnosis of marginal zone lymphomas, including the difficulties in the distinction between splenic marginal zone lymphoma, splenic diffuse red pulp lymphoma, and hairy cell leukemia variant/splenic B-cell lymphoma with prominent nucleoli which requires integration of clinical features, immunophenotype, and morphology in blood, bone marrow, and spleen; cases of marginal zone lymphoma with markedly increased TFH-cells, simulating a T-cell lymphoma, where molecular studies (clonality and mutation detection) can help to establish the final diagnosis; the criteria for transformation of marginal zone lymphomas, which are still unclear and might require the integration of morphological and molecular data; the concept of an overlapping spectrum between pediatric nodal marginal zone lymphoma and pediatric-type follicular lymphoma; and the distinction between pediatric nodal marginal zone lymphoma and "atypical" marginal zone hyperplasia, where molecular studies are mandatory to correctly classify cases.

Emerging entities: high-grade/large B-cell lymphoma with 11q aberration, large B-cell lymphoma with IRF4 rearrangement, and new molecular subgroups in large B-cell lymphomas. A report of the 2022 EA4HP/SH lymphoma workshop.

Emerging entities and molecular subgroups in large B-cell lymphomas (LBCLs) were discussed during the 2022 European Association for Haematopathology/Society for Hematopathology workshop in Florence, Italy. This session focused on newly recognized diseases and their diagnostic challenges. High-grade/large B-cell lymphoma with 11q aberration (HG/LBCL-11q) is defined by chromosome 11q-gains and telomeric loss. FISH analysis is recommended for the diagnosis. HG/LBCL-11q can occur in the setting of immunodeficiency, including ataxia-telangiectasia, and predominates in children. The morphological spectrum of these cases is broader than previously thought with often Burkitt-like morphology and coarse apoptotic bodies. It has a Burkitt-like immunophenotype (CD10+, BCL6+, BCL2-) but MYC expression is weak or negative, lacks MYC rearrangement, and is in contrast to Burkitt lymphoma 50% of the cases express LMO2. LBCL with IRF4 rearrangement (LBCL-IRF4) occurs mainly in the pediatric population but also in adults. LBCL-IRF4 has an excellent prognosis, with distinguishing molecular findings. IRF4 rearrangements, although characteristic of this entity, are not specific and can be found in association with other chromosomal translocations in other large B-cell lymphomas. Other molecular subgroups discussed included primary bone diffuse large B-cell lymphoma (PB-DLBCL), which has distinctive clinical presentation and molecular findings, and B-acute lymphoblastic leukemia (B-ALL) with IGH::MYC translocation recently segregated from Burkitt lymphoma with TdT expression. This latter disorder has molecular features of precursor B-cells, often tetrasomy 1q and recurrent NRAS and KRAS mutations. In this report, novel findings, recommendations for diagnosis, open questions, and diagnostic challenges raised by the cases submitted to the workshop will be discussed.

Cytotoxic peripheral T-cell lymphomas and EBV-positive T/NK-cell lymphoproliferative diseases: emerging concepts, recent advances, and the putative role of clonal hematopoiesis. A report of the 2022 EA4HP/SH lymphoma workshop.

Cytotoxic peripheral T-cell lymphomas and EBV-positive T/NK-cell lymphoproliferative diseases were discussed at the 2022 European Association for Haematopathology/Society for Hematopathology lymphoma workshop held in Florence, Italy. This session focused on (i) primary nodal EBV-positive T and NK-cell lymphomas (primary nodal-EBV-TNKL), (ii) extranodal EBV-positive T/NK lymphoproliferative diseases (LPD) in children and adults, (iii) cytotoxic peripheral T-cell lymphomas, NOS (cPTCL-NOS), EBV-negative, and (iv) miscellaneous cases. Primary nodal-EBV-TNKL is a newly recognized entity which is rare, aggressive, and associated with underlying immune deficiency/immune dysregulation. All cases presented with lymphadenopathy but some demonstrated involvement of tonsil/Waldeyer's ring and extranodal sites. The majority of tumors are of T-cell lineage, and the most frequent mutations involve the epigenetic modifier genes, such as TET2 and DNMT3A, and JAK-STAT genes. A spectrum of EBV-positive T/NK LPD involving extranodal sites were discussed and highlight the diagnostic challenge with primary nodal-EBV-TNKL when these extranodal EBV-positive T/NK LPD cases demonstrate predominant nodal disease either at presentation or during disease progression from chronic active EBV disease. The majority of cPTCL-NOS demonstrated the TBX21 phenotype. Some cases had a background of immunosuppression or immune dysregulation. Interestingly, an unexpected association of cPTCL-NOS, EBV-positive and negative, with TFH lymphomas/LPDs was observed in the workshop cases. Similar to a published literature, the genetic landscape of cPTCL-NOS from the workshop showed frequent mutations in epigenetic modifiers, including TET2 and DNMT3A, suggesting a role of clonal hematopoiesis in the disease pathogenesis.

Follicular helper T-cell lymphomas: disease spectrum, relationship with clonal hematopoiesis, and mimics. A report of the 2022 EA4HP/SH lymphoma workshop.

Follicular helper T-cell lymphomas (TFH lymphomas) were discussed in session V of the lymphoma workshop of the European Association for Haematopathology (EA4HP)/Society for Hematopathology (SH) 2022 meeting in Florence, Italy. The session focused on the morphologic spectrum of TFH lymphoma, including its three subtypes: angioimmunoblastic-type (AITL), follicular-type, and not otherwise specified (NOS). The submitted cases encompassed classic examples of TFH lymphoma and unusual cases such as those with early or indolent presentations, associated B-cell proliferations, or Hodgkin/Reed-Sternberg-like cells. The relationship between TFH lymphoma and clonal hematopoiesis was highlighted by several cases documenting divergent evolution of myeloid neoplasm and AITL from shared clonal mutations. The distinction between TFH lymphoma and peripheral T-cell lymphoma, not otherwise specified (PTCL, NOS), was stressed, and many challenging examples were presented. Various cases highlighted the difficulties of differentiating TFH lymphoma from other established types of lymphoma and reactive conditions. Cutaneous T-cell lymphoma expressing TFH markers, particularly when resulting in lymph node involvement, should be distinguished from TFH lymphomas. Additional immunophenotyping and next-generation sequencing studies were performed on various cases in this session, highlighting the importance of these technologies to our current understanding and classification of TFH lymphomas.

Phase II study of dose-adjusted EPOCH as initial therapy for adults with high-risk acute lymphoblastic leukemia.

Treatments for adults with newly-diagnosed acute lymphoblastic leukemia (ALL) may be prohibitively toxic and/or resource-intense. To address this, we performed a phase II study of dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin (DA-EPOCH). Imatinib or dasatinib was added for Ph + disease; rituximab was added when CD20+. Fifty-three patients were evaluable: 28 with Ph + disease, and 25 with Ph-. All patients had ≥1 high-risk clinical feature. Measurable residual disease-negativity by multiparameter flow cytometry within 4 cycles was achieved in 71% in patients with Ph + ALL and 64% in Ph - ALL. Median overall survival (OS) was 49 months, with a 2-year OS of 71%. Median relapse-free survival (RFS) in the 47 patients that attained morphologic remission was 24 months, with a 2-year RFS of 57%. Early mortality was 2%. In summary, DA-EPOCH yields deep and durable remissions in adults with ALL comparable to some resource-intense strategies but with a low rate of treatment-related death.

The impact of histological grade on outcomes in follicular lymphoma: An analysis of patients in the SEER database in the context of evolving disease classification and treatment.

Currently, there is no convincing evidence that the grade of follicular lymphoma (FL) impacts patient outcome. We correlated grades in 33 925 patients with nodal FL during 1992-2018 in the SEER database with disease-specific survival (DSS) and overall survival (OS). Patients with FL grade 3 had lower DSS and OS as compared to FL grades 1-2. During 1992-2005, the 10-year DSS for patients with FL grades 3 and grades 1-2 were 68.6%, and 71.4%, respectively, and in 2006-2018, they were 77.7% and 82.6%, respectively. The 10-year OS estimates in 1992-2005 were 49.9% and 54.2% for grade 3 and grades 1-2 respectively, and in 2006-2018, they were 59.1% and 63.5% for grade 3 and grades 1-2, respectively. After adjustment for stage and age, the hazard ratios for death due to FL and death from any cause for patients with FL grade 3 during 1992-2005 were 1.09 (1.02-1.16) and 1.07 (1.02-1.12), respectively, compared to FL grades 1-2; and during 2006-2018, the hazard ratios for death due to FL and death from any cause for patients with FL grade 3 were 1.34 (1.22-1.45) and 1.16 (1.10-1.23), respectively compared to FL grades 1-2. The grade of FL is an important determinant of disease biology.

Lamin B1 deletion in myeloid neoplasms causes nuclear anomaly and altered hematopoietic stem cell function.

Abnormal nuclear morphology is a hallmark of malignant cells widely used in cancer diagnosis. Pelger-Huët anomaly (PHA) is a common abnormality of neutrophil nuclear morphology of unknown molecular etiology in myeloid neoplasms (MNs). We show that loss of nuclear lamin B1 (LMNB1) encoded on chromosome 5q, which is frequently deleted in MNs, induces defects in nuclear morphology and human hematopoietic stem cell (HSC) function associated with malignancy. LMNB1 deficiency alters genome organization inducing in vitro and in vivo expansion of HSCs, myeloid-biased differentiation with impaired lymphoid commitment, and genome instability due to defective DNA damage repair. Nuclear dysmorphology of neutrophils in patients with MNs is associated with 5q deletions spanning the LMNB1 locus, and lamin B1 loss is both necessary and sufficient to cause PHA in normal and 5q-deleted neutrophils. LMNB1 loss thus causes acquired PHA and links abnormal nuclear morphology with HSCs and progenitor cell fate determination via genome organization.

Clinicopathologic Findings in Patients With Initial Diagnosis of Extranodal Marginal Zone B-Cell Lymphoma of Mucosa-Associated Lymphoid Tissue (MALT) in Colorectal Mucosa.

OBJECTIVES: To evaluate clinicopathologic features, management, and behavior of colorectal extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT). METHODS: Clinical data, laboratory studies, and radiographic records were reviewed (2005-2018), and fluorescence in situ hybridization studies were performed. RESULTS: Eleven patients were identified, six of whom were discovered as an incidental finding on endoscopy. Morphologic and immunophenotypic features were similar to MALT lymphomas at other sites except that lymphoepithelial lesions were uncommon. Three of nine patients were positive for BIRC3/MALT1 fusions, two of whom had identical B-cell clones identified in subsequent gastric biopsy specimens. Eight of 10 patients had no clinically evaluable disease after observation (±antibiotics; n = 4) or radiation/chemotherapy (n = 4). CONCLUSIONS: Patients with incidental and localized colonic MALT lymphoma demonstrated an excellent prognosis with conservative management, although longer follow-up and data based on consistent staging and surveillance methods (including gastric evaluation) are necessary for informed management.

Genomic landscape of Epstein-Barr virus-positive extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue.

Epstein-Barr virus (EBV)-positive extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT lymphomas) were initially described in solid organ transplant recipients, and, more recently, in other immunodeficiency settings. The overall prevalence of EBV-positive MALT lymphomas has not been established, and little is known with respect to their genomic characteristics. Eight EBV-positive MALT lymphomas were identified, including 1 case found after screening a series of 88 consecutive MALT lymphomas with EBER in situ hybridization (1%). The genomic landscape was assessed in 7 of the 8 cases with a targeted high throughput sequencing panel and array comparative genomic hybridization. Results were compared to published data for MALT lymphomas. Of the 8 cases, 6 occurred post-transplant, 1 in the setting of primary immunodeficiency, and 1 case was age-related. Single pathogenic/likely pathogenic mutations were identified in 4 of 7 cases, including mutations in IRF8, BRAF, TNFAIP3, and SMARCA4. Other than TNFAIP3, these genes are mutated in <3% of EBV-negative MALT lymphomas. Copy number abnormalities were identified in 6 of 7 cases with a median of 6 gains and 2 losses per case, including 4 cases with gains in regions encompassing several IRF family or interacting genes (IRF2BP2, IRF2, and IRF4). There was no evidence of trisomies of chromosomes 3 or 18. In summary, EBV-positive MALT lymphomas are rare and, like other MALT lymphomas, are usually genetically non-complex. Conversely, while EBV-negative MALT lymphomas typically show mutational abnormalities in the NF-κB pathway, other than the 1 TNFAIP3-mutated case, no other NF-κB pathway mutations were identified in the EBV-positive cases. EBV-positive MALT lymphomas often have either mutations or copy number abnormalities in IRF family or interacting genes, suggesting that this pathway may play a role in these lymphomas.

Entrustable Professional Activities in Hematopathology Pathology Fellowship Training: Consensus Design and Proposal.

Hematopathology fellowship education has grown in complexity as patient-centered treatment plans have come to depend on integration of clinical, morphologic, immunophenotypic, molecular, and cytogenetic variables. This complexity is in competition with the need for timely hematopathology care with stewardship of patient, laboratory, and societal resources. Accreditation Council for Graduate Medical Education Milestones provide a guidance document for hematopathology training, but fellows and their educators are in need of a simple framework that allows assessment and feedback of growth toward independent hematopathology practice. Entrustable professional activities provide one such framework, and herein, we provide proposed Hematopathology Fellowship Entrustable Professional Activities based on review of pertinent guidelines and literature, with multiple rounds of expert and stakeholder input utilizing a modified mini-Delphi approach. Ten core entrustable professional activities deemed essential for graduating hematopathology fellows were developed together with skills and knowledge statements, example scenarios, and corresponding Accreditation Council for Graduate Medical Education Milestones. Application of these entrustable professional activities in program design, fellow evaluation, and decisions regarding level of supervision is discussed with consideration of benefits and barriers to implementation. These entrustable professional activities may be used by hematopathology fellowship directors and faculty to provide fellows with timely constructive feedback, determine entrustment decisions, provide the Clinical Competency Committee with granular data to support Milestone evaluations, and provide insight into areas of potential improvement in fellowship training. Fellows will benefit from a clear roadmap to independent hematopathology practice with concrete and timely feedback.

Ibrutinib Monotherapy in Relapsed or Refractory, Transformed Diffuse Large B-cell Lymphoma.

BACKGROUND: Histologic transformation to diffuse large B-cell lymphoma (tDLBCL) occurs in a significant proportion of indolent lymphomas. However, few studies of novel agents inform its management, particularly when relapsed after or refractory (R/R) to prior treatment. PATIENTS AND METHODS: We prospectively evaluated ibrutinib monotherapy in pathologically documented patients with R/R tDLBCL in a single-arm study. The primary endpoint was overall response rate. RESULTS: Twenty patients who had received a median of 4 (range, 2-9) prior lines of therapy overall (median, 2.5; range, 1-9 for tDLBCL) were treated. The overall response rate was 35%, including complete responses in 15%. The median progression-free survival and overall survival were 4.1 months (95% confidence interval, 2.4-6.2 months) and 22.4 months (95% confidence interval, 7.5 months to not reached), respectively. Disease control > 2 months was seen in 75% and > 1 year in 15%. Response was associated with either low tumor bulk or low metabolic tumor volume (P = .05) but not with antecedent lymphoma histology (P = 1.0). Treatment-related adverse events were consistent with prior studies of ibrutinib. CONCLUSIONS: Ibrutinib showed low toxicity and meaningful efficacy in R/R tDLBCL, including short-term disease control in most cases. Results demonstrate the potential utility of ibrutinib in this challenging clinical setting, including as a potential bridge to more definitive treatments.

How I Diagnose Minimal/Measurable Residual Disease in B Lymphoblastic Leukemia/Lymphoma by Flow Cytometry.

OBJECTIVES: Assessment for minimal/measurable residual disease (MRD) is a powerful prognostic factor in B lymphoblastic leukemia/lymphoma (B-LL/L) that is quickly becoming standard of care in assessing patients with B-LL/L posttherapy. MRD can be assessed using methodologies including flow cytometry and molecular genetics, with the former being rapid, relatively inexpensive, and widely applicable in many hematopathology/flow cytometry laboratories. METHODS: This article presents an approach to MRD detection in B-LL/L by flow cytometry through case presentations with illustration of several potential pitfalls. We review normal maturation patterns, antigens used for assessment, flow panels that can be utilized, considerations to be made during therapy, and clinical impact. The benefits and drawbacks when using the "different from normal" and "leukemia associated phenotype" approaches are considered. RESULTS: Evaluation for MRD in B-LL/L by flow cytometry relies on a knowledge of normal immunophenotypic patterns associated with B-cell maturation in states of rest and marrow regeneration so that one can identify patterns of antigen expression that differentiate abnormal, leukemic populations from regenerating hematogones or B-cell precursors. The nature of therapy can affect normal patterns, a phenomenon especially important to take into consideration given the increased use of targeted therapies in the treatment of B-LL/L. CONCLUSIONS: Flow cytometry is widely available in many laboratories and is a cost-effective way to evaluate for B-LL/L MRD. However, panel validation and interpreter education are crucial for accurate assessment.

CD33 expression on natural killer cells is a potential confounder for residual disease detection in acute myeloid leukemia by flow cytometry.

Detection of minimal/measurable residual disease (MRD) in acute myeloid leukemia (AML) is important for guiding patient-specific clinical management. Natural killer (NK) cells can express various markers not typically associated with NK lineage, potentially confounding the detection of MRD by flow cytometry. We have observed CD33 expression on NK cells when evaluating for AML MRD in routine clinical practice in multiple patient samples. To characterize CD33 expression on NK cells, 40 peripheral blood or bone marrow samples with NK cells present at >5% of lymphocytes were selected for further assessment of NK cell phenotype and CD33 expression. Seven of the 40 samples (17.5%) were found to have CD33 expression on at least 5% of the NK cells. The CD33-positive NK cell population accounted for an average of 11.4% of NK cells (median 11.9%, range 8.0-15.3%) and 2.2% of total white cells (median 1.1%, range 0.1-10.1%). This NK cell subset expressed bright CD2, bright CD56, and dim CD16. On average, CD33 expression on NK cells was dimmer than on monocytes (mean median fluorescence intensity ratio 0.4; range 0.1-1.0). This study characterizes expression of CD33 on NK cells. Recognition of this pattern of antigen expression is critical in evaluating samples for MRD in patients with myeloid neoplasms, particularly AML.

Molecular and Cytogenetic Education in Hematopathology Fellowship.

OBJECTIVES: Given the increased complexity of molecular and cytogenetic testing (MOL-CG), the Society for Hematopathology Education Committee (SH-EC) was interested in determining what the current expectations are for MOL-CG education in hematopathology (HP) fellowship training. METHODS: The SH-EC sent a questionnaire to HP fellowship program directors (HP-PDs) covering MOL-CG training curricula, test menus, faculty background, teaching, and sign-out roles. These findings were explored via a panel-based discussion at the 2018 SH-EC meeting for HP-PDs. RESULTS: HP fellows are expected to understand basic principles, nomenclature, and indications for and limitations of testing. Interpretation of common assays is within that scope, but not necessarily proficiency in technical troubleshooting of testing or analysis of complex raw data. CONCLUSIONS: The consensus was that HP fellows should understand the components of MOL-CG testing necessary to incorporate those results into an accurate, clinically relevant, and integrated HP report.

Outcomes of Patients With Therapy-Related MDS After Chemoimmunotherapy for Chronic Lymphocytic Leukemia Compared With Patients With De Novo MDS: A Single-Institution Experience.

BACKGROUND: Patients with chronic lymphocytic leukemia (CLL) treated with chemoimmunotherapy are at increased risk of developing therapy-related (t-) myelodysplastic syndrome (MDS). It is unclear whether antecedent CLL adds prognostic value to the revised International Prognostic Scoring System (IPSS-R) for MDS. We performed a retrospective analysis to evaluate the significance of a previous CLL diagnosis as an independent adverse prognostic factor. PATIENTS AND METHODS: We identified 18 consecutive patients with t-MDS, previously treated for CLL (CLL-MDS) from 2002 to 2016. For each CLL-MDS patient, we identified 2 control patients with de novo MDS matched for age (≤ 65 or > 65 years), IPSS-R (≤ 3 or > 3), and year of MDS diagnosis (before or after 2008). Multivariable models were developed to test for independent predictors of progression to acute myeloid leukemia (AML) and overall survival (OS). RESULTS: Median time from CLL to MDS diagnosis was 58.8 months (range, 12-280 months) and median number of treatment lines for CLL was 1 (range, 1-5), including alkylating agents in 15 patients (83%) and fludarabine, cyclophosphamide, rituximab in 12 patients (67%). Hypomethylating agents were administered in 13 (72%) of CLL-MDS patients and 33 (91%) of de novo MDS patients. After a median follow-up of 19.2 months, OS was not different between CLL-MDS and matched de novo MDS patients. CLL-MDS patients with IPSS-R score ≤ 3 had better OS compared with those with IPSS-R score > 3. In multivariate analysis, there was no significant independent association between history of CLL OS or progression to AML. CONCLUSION: History of CLL did not independently affect OS in t-MDS patients beyond IPSS-R score.