Refining Diagnostic Subtypes of Peripheral T-Cell Lymphoma Using a Multiparameter Approach.

Peripheral T-cell lymphoma (PTCL) is a heterogeneous group of neoplasms, with many cases remaining unclassifiable and categorized as PTCL-not otherwise specified (PTCL-NOS). Gene expression profiling (GEP) has delineated 2 prognostic subtypes within PTCL-NOS, PTCL-TBX21 and PTCL-GATA3, characterized by distinctive transcriptomes and a different prognosis. To further evaluate the pathologic features of these subgroups, 101 PTCL cases that did not meet specific criteria for well-defined T-cell lymphoma entities underwent detailed pathologic, immunophenotypic (including T follicular helper [T] biomarkers), and GEP analyses, separating them into PTCL-NOS (n = 63) and PTCL-TFH (also known as nodal PTCL-TFH, NOS, and TFH lymphoma, NOS) (n = 38).

Closing the gap between biology and classification in splenic B-cell lymphomas.

The mature splenic B-cell lymphomas are an enigmatic group of lymphoid neoplasms that have long caused significant difficulty for the practicing pathologist due to overlapping diagnostic features among entities and the decreasing availability of splenic tissue for assessment. While some entities have highly characteristic and specific clinicopathological features (e.g.

Expression of CD6 in Aggressive NK/T-cell Neoplasms and Assessment as a Potential Therapeutic Target: A Bone Marrow Pathology Group Study.

Background: Aggressive NK/T-Cell neoplasms are rare hematological malignancies characterized by the abnormal proliferation of NK or NK-like T (NK/T) cells. CD6 is a transmembrane signal transducing receptor involved in lymphocyte activation and differentiation. This study aimed to investigate the CD6 expression in these malignancies and explore the potential of targeting CD6 in these diseases.

Motive and opportunity: MYC rearrangements in high-grade B-cell lymphoma with MYC and BCL2 rearrangements (an LLMPP study).

Rearrangements that place the oncogenes MYC, BCL2, or BCL6 adjacent to superenhancers are common in mature B-cell lymphomas. Lymphomas with diffuse large B-cell lymphoma (DLBCL) or high-grade morphology with both MYC and BCL2 rearrangements are classified as high-grade B-cell lymphoma with MYC and BCL2 rearrangements ("double hit"; HGBCL-DH-BCL2) and are associated with aggressive disease and poor outcomes. Although it is established that MYC rearrangements involving immunoglobulin (IG) loci are associated with inferior outcomes relative to those involving other non-IG superenhancers, the frequency of and mechanisms driving IG vs non-IG MYC rearrangements have not been elucidated.

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.

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.

CD6-targeted antibody-drug conjugate as a new therapeutic agent for T cell lymphoma.

T cell lymphomas (TCL) are heterogeneous, aggressive, and have few available targeted therapeutics. In this study, we determined that CD6, an established T cell marker, was expressed at high levels on almost all examined TCL patient specimens, suggesting that CD6 could be a new therapeutic target for this life-threatening blood cancer. We prepared a CD6-targeted antibody-drug conjugate (CD6-ADC) by conjugating monomethyl auristatin E (MMAE), an FDA-approved mitotic toxin, to a high-affinity anti-human CD6 monoclonal antibody (mAb).

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.

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.

Ki67 proliferation index in follicular lymphoma is associated with favorable outcome in patients treated with R-CHOP.

Follicular lymphoma (FL) is a common, indolent small B-cell lymphoma. While the Follicular Lymphoma International Prognostic Index is widely used, reliable prognostic and predictive biomarkers are needed. A recent study suggested that architectural patterns of CD10, BCL6, and Ki67 expression may correlate with progression-free survival (PFS) in FL patients treated with chemotherapy-free regimens.

Characterization of Samples with Minor P3 Peak Elevations in a High Pressure Liquid Chromatography System for HbA1c: Contributions of Hemoglobin Variants and Storage Conditions.

Background: In the Bio-Rad D-100TM (Bio-Rad, Hercules, CA) HPLC system for hemoglobin A1c (HbA1c) measurement, 7 peaks elute: HbA1a, HbA1b, HbF, LA1c, HbA1c, P3, and HbA0. HbA1c is calculated from the ratio of the HbA1c peak area to the total area, excluding HbF and peaks after HbA0, if present. A P3 peak >10% flags for potential interferences.

Oil Red O Staining of Pulmonary Macrophages in Bronchoalveolar Lavage Specimens Is Not Specific for Vaping-Associated Lung Injury.

Objectives: Oil Red O (ORO) positivity in bronchoalveolar lavage (BAL) fluid macrophages in the setting of e-cigarette, or vaping, product use-associated acute lung injury (EVALI) has been frequently requested by clinicians based on rare reports and subsequent US Centers for Disease Control and Prevention guidelines. The aim of this study was to determine the specificity of ORO staining in BAL specimens with disease states other than EVALI.

Methods: Consecutive BAL specimens (October-December 2019) were stained with ORO.

Gene Expression Signatures for the Accurate Diagnosis of Peripheral T-Cell Lymphoma Entities in the Routine Clinical Practice.

Purpose: Peripheral T-cell lymphoma (PTCL) includes heterogeneous clinicopathologic entities with numerous diagnostic and treatment challenges. We previously defined robust transcriptomic signatures that distinguish common PTCL entities and identified two novel biologic and prognostic PTCL-not otherwise specified subtypes (PTCL-TBX21 and PTCL-GATA3). We aimed to consolidate a gene expression-based subclassification using formalin-fixed, paraffin-embedded (FFPE) tissues to improve the accuracy and precision in PTCL diagnosis.

Signet-ring cells in pleural and peritoneal effusions identified on Wright stains - A diagnostic pitfall.

Objectives: Signet-ring cells (SRCs) in effusion specimens represent a diagnostic challenge. In this study, a consecutive series of pleural and peritoneal effusions with benign SRCs are examined and compared with malignant SRCs.

Material And Methods: We reviewed consecutive Wright-stained serous effusion slides and searched for cases with SRCs.

Ophthalmic Manifestations of Hodgkin Lymphoma: A Review.

Background: Hodgkin lymphoma (HL) is a hematopoietic neoplasm characterized by cancerous Reed-Sternberg cells. In contrast to ophthalmic manifestations by non-HL that are well recognized, there is paucity of the literature as it relates to ophthalmic manifestation by HL. We performed a comprehensive review of published studies (case reports and small case series) to characterize the ophthalmic manifestations of HL.

A comprehensive analysis of cytopenias and bone marrow morphology in patients with a history of bariatric and metabolic surgery.

Introduction: Following bariatric and metabolic surgery (BMS), patients may develop persistent cytopenia(s) despite adequate micronutrient levels. A comprehensive analysis of laboratory and hematopathologic findings in BMS patients with unexplained cytopenia(s) has not been previously described.

Methods: We reviewed the clinical and laboratory data, bone marrow histology, and used ancillary testing to characterize patients with a history of BMS who had subsequent bone marrow biopsies due to unexplained cytopenia(s).

Pathology Residents as Testing Personnel in the Hematology Laboratory.

Context.—: Clinical laboratories and the training of pathology residents are tightly regulated environments. Compliance with regulatory requirements must be addressed when developing entrustable professional activities (EPAs) for pathology residents.

How I Diagnose Primary Mediastinal (Thymic) Large B-Cell Lymphoma.

Objectives: Primary mediastinal (thymic) large B-cell lymphoma (PMBL) is an uncommon large B-cell neoplasm recognized by the World Health Organization as a distinct entity on the basis of its unique clinical features, histogenesis, phenotype, and pathogenetic mechanisms. The diagnosis of PMBL can be challenging because of features that may overlap with other (Hodgkin and non-Hodgkin) lymphoma types. This review describes our approach to the diagnosis of PMBL.