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.

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.

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.

Assessing the added value of bone marrow morphologic evaluation beyond flow cytometry for disease detection in the setting of acute myeloid leukemia after chemotherapy

Complete response after acute myeloid leukemia (AML) therapy historically requires a decrease in bone marrow (BM) blasts to &lt;5% by morphologic assessment. However, accumulating data indicate that measurable residual disease by more sensitive multiparameter flow cytometry (MFC) is a better predictor of outcome than traditional morphologic evaluation. In most cases, morphology alone cannot differentiate between regenerative and neoplastic blasts, raising the question of its added value to more specific MFC. The objective of this study was to assess the value morphologic evaluation adds to MFC for the detection of residual AML in the post-chemotherapy (induction or consolidation) setting. A search of our pathology database identified 47 consecutive nontransplant BM evaluations (41 total patients) in the post-chemotherapy setting between January and March 2020. The morphology portion for each case was reviewed by three independent hematopathologists for evaluation of adequacy (&gt;200 cells), blast count, trilineage hematopoiesis, dysplastic features, focal/patchy disease, and any non-hematopoietic or alternative diagnoses that would not have been discovered by the associated MFC study. The MFC data for each case was separately reviewed by two hematopathologists. Six of the 47 cases showed &gt;5% blasts by morphology (range 8%-70%); in all six cases, &gt;5% abnormal blasts were also identified by MFC (range 23%-78%). Of cases with &lt;5% blasts by morphology (defined as negative by morphology), MFC detected &gt;5% abnormal blasts in four cases and &lt;5% abnormal blasts in five cases (range 0.007-14%). One of these additional nine cases by MFC was identified to have focally clustered blasts by morphology (7% blasts by MFC, &lt;5% overall by morphology). Two of the nine additional cases by MFC were deemed to have inadequate aspirates by morphology. In total, four of the 47 morphology cases had inadequate aspirate smears (9%). Of these four cases, three had adequate particle preparations. Eleven cases overall had corresponding core biopsies submitted, of which five were inadequate (45%). Morphologic examination identified seven cases with dysplastic features; abnormal blasts were identified in four of these cases by MFC (all &gt;5% blasts). In the remaining three cases with dysplasia, ancillary molecular studies supported molecular evidence of residual disease in one case (NPM1 mutation and FLT3-ITD positivity by PCR). No unexpected carcinomas or other findings that would not be detected by the associated MFC study were identified. In conclusion, in our study, morphologic evaluation did not definitively identify any additional cases of residual/recurrent AML that were not identified by MFC. Morphologic evaluation detected dysplasia without abnormal blasts in three cases; however, the significance was unclear without supportive molecular studies. Reducing the number of cases for morphologic evaluation could save resources and improve turnaround time if MFC can provide the relevant details to assess response.

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.

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.

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.

Targeted therapy for Hodgkin lymphoma and systemic anaplastic large cell lymphoma: focus on brentuximab vedotin

Despite the relative success of chemotherapy for Hodgkin lymphoma (HL) and systemic anaplastic large cell lymphoma (ALCL), novel therapeutic agents are needed for refractory or relapsed patients. Targeted immunotherapy has emerged as a novel treatment option for these patients. Although unconjugated anti-cluster of differentiation (CD)30 antibodies showed minimal antitumor activity in early clinical trials, development of antibody–drug conjugates (ADCs) appears promising. Brentuximab vedotin is an ADC composed of an anti-CD30 antibody linked to a potent microtubule-disrupting agent monomethyl auristatin E (MMAE). It has the ability to target CD30-positive tumor cells and, once bound to CD30, brentuximab vedotin is internalized and MMAE is released to induce cell cycle arrest and apoptosis. In two Phase II trials, objective response was reported in 75% and 86% of patients with refractory or relapsed HL and systemic ALCL, respectively, with an acceptable toxicity profile. Based on these studies, the US Food and Drug Administration (FDA) granted accelerated approval of brentuximab vedotin in August 2011 for the treatment of refractory and relapsed HL and ALCL. We review the key characteristics of brentuximab vedotin, clinical data supporting its therapeutic efficacy, and current ongoing trials to explore its utility in other CD30-positive malignancies.

Durable remission of HIV-negative, Kaposi’s sarcoma herpes virus-associated multicentric Castleman disease in patient with rheumatoid arthritis treated with methotrexate

Multicentric Castleman disease (MCD) is a nonneoplastic lymphoproliferative disorder that has a poor prognosis. Optimal treatment is unknown. There are a few reported cases of MCD and rheumatoid arthritis. In this study, we report a patient with rheumatoid arthritis diagnosed with Kaposi's sarcoma herpesvirus-(KSHV, human herpesvirus-8) associated MCD that showed expression of viral IL-6. Treatment with methotrexate (MTX) resulted in a complete remission of her disease lasting for 54+ months. Multiple studies have suggested that MCD and rheumatoid arthritis are associated with overexpression of the growth-promoting cytokine interleukin-6 (IL-6), and that MTX downregulates the production of this cytokine in vivo. As such, we suggest that the dramatic improvement in this patient's disease is due to the immunomodulatory properties of MTX.

Splenic small B-cell lymphoma with IGH/BCL3 translocation

Isolated chromosomal translocations are important defining features of many non-Hodgkin lymphomas, especially of B-cell type. In contrast to some other translocations, the significance of IGH/BCL3 translocations is not well defined. Although often considered a feature of the ill-defined entity atypical chronic lymphocytic leukemia, very few cases are reported in which involvement of BCL3 and the precise B-cell neoplasm are both well documented. For this reason, we report a splenic-based CD5(-), CD10(-), CD43(-), CD23(-), CD103(-), FMC7(+), CD25(+) small B-cell lymphoma associated with epithelioid histiocyte clusters and a t(14;19)(q32;q13) representing an IGH/BCL3 translocation based on classical cytogenetic studies, chromosomal painting, and fluorescence in situ hybridization studies. The previously reported neoplasms with t(14;19)(q32;q13) or IGH/BCL3 translocations are also reviewed. The present case did not fall into any of the classic B-cell lymphoma categories and clearly did not represent chronic lymphocytic leukemia/small lymphocytic lymphoma. This case suggests that the IGH/BCL3 translocation may help to define a new clinicopathologic entity.

The proliferation center microenvironment and prognostic markers in chronic lymphocytic leukemia/small lymphocytic lymphoma

Prognostication in chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) based, in part, on ZAP-70 and CD38 expression, and to a lesser extent, on MUM1/IRF4 expression, is currently of great interest. The more aggressive type of CLL/SLL is reportedly characterized by neoplastic cells that are more responsive to B-cell signaling with proliferation centers (PCs), a potentially important site of neoplastic cell stimulation. To study the relationship of these markers to each other and to the pattern of PCs, immunohistochemical stains for ZAP-70 and MUM1/IRF4 were performed and the PC patterns assessed (where possible) in 29 tissue biopsies with CLL/SLL. CD38 expression was assessed in 18 cases using flow cytometry. Ten evaluable cases had a typical PC pattern and 16 an atypical pattern with larger or more confluent PCs and/or more numerous paraimmunoblasts/transformed cells. ZAP-70 was positive in 14 of 28 cases, including 3 with atypical PCs and enhanced PC staining. All 29 cases showed MUM1/IRF4 expression in PCs. Seven cases, none with atypical PC, also showed uniform positivity throughout, 14 showed weaker staining of surrounding lymphocytes, and 8 had PC staining only. CD38 was positive in 14 of 18 cases. The only significant association identified was between uniform MUM1/IRF4 positivity and typical PCs (P = .004). These findings highlight the complex interrelationship of prognostic markers in CLL/SLL and demonstrate potentially important microenvironmental variations in their expression. They support the hypothesis that PCs are a site for B-cell receptor signaling, which helps explain reported site-dependent antigenic variation in CLL/SLL, and suggest that PC morphology may correlate with other biological features.

Microglia in diseases of the central nervous system

Microglia (MG) are enigmatic cells of the central nervous system (CNS). MG are morphologically, antigenically and functionally flexible, and have the potential for mobility and proliferation. MG are professional antigen-presenting cells and constitute part of the local CNS innate immune system, communicating with other immune cells via chemokines, cytokines and growth factors. MG contain several antigenic and functional markers similar to macrophages and dendritic cells (DCs), but also present several differences from DCs. The exact role(s) played by MG in the normal human CNS is the topic of lively debate. MG participate in many reactive processes in the CNS and are therefore an integral part of lesions in a variety of pathologic conditions. It is thought that MG may exacerbate diverse neurological conditions, including viral encephalitis, AIDS, Multiple Sclerosis (MS) and Alzheimer's disease. A recurrent theme is the perpetuation by MG of pathological cycles of monocyte recruitment, activation and cytopathic secretions, and/or auto antigen presentation.