Clinical Applications of Bone Marrow CD34 Immunohistochemistry (BM CD34 IHC) Assay: International Council for Standardization in Hematology (ICSH) Guidelines.

Introduction: Investigation of bone marrow (BM) trephine biopsies and/or clot sections by CD34 immunohistochemistry (IHC) testing has been used by pathologists for several decades, and its clinical value has been well established with QBEND10 being the most frequently used primary antibody (Ab) clone. However, most other parameters related to the IHC protocol as well as the readout vary widely between clinical laboratories and in the published literature. The ICSH Working Group having reviewed the published evidence has established guidelines that will help to harmonize performance and reporting of CD34 IHC on BM biopsies.

Primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorders: demographic, clinical, therapeutic and prognostic aspects. A retrospective monocentric analysis.

Primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorders (PCSM-LPDs), represent a rare group of haematological diseases primarily affecting the skin. In this retrospective single-centre case series study, we aimed to investigate the demographic, clinical, therapeutic and prognostic aspects of PCSM-LPD. We collected data from cases diagnosed between 2010 and the present, employing histopathological and immunohistochemical methods following the World Health Organization criteria.

The Dark Side of Activated Phosphoinositide 3-Kinase-δ Syndrome 2: A Story Rewritten through FDG-PET.

Activated phosphoinositide 3-kinase-δ syndrome 2 (APDS2) is characterized by lymphoproliferation and increased risk of malignancy. FDG-PET/CT may represent a helpful diagnostic tool for differentiating these clinical features and correctly diagnosing inborn errors of immunity (IEI). We present the case of a female patient diagnosed with Hodgkin's lymphoma at 19 years of age, although atypical imaging aspects emerged: baseline FDG-PET/CT revealed several hot lymph nodes with a symmetrical distribution, and increased tracer uptake in spleen, axial, and appendicular bone marrow.

The Role of Cytokines in Cutaneous T Cell Lymphoma: A Focus on the State of the Art and Possible Therapeutic Targets.

Cutaneous T cell lymphomas (CTCLs), encompassing mycosis fungoides (MF) and Sézary syndrome (SS), present a complex landscape influenced by cytokines and cellular responses. In this work, the intricate relationship between these inflammatory proteins and disease pathogenesis is examined, focusing on what is known at the clinical and therapeutic levels regarding the most well-known inflammatory mediators. An in-depth look is given to their possible alterations caused by novel immunomodulatory drugs and how they may alter disease progression.

Rapidly progressive dementia due to intravascular lymphoma: A prion disease reference center experience.

Background: Intravascular large B-cell lymphoma (IVLBCL) is a rare extranodal lymphoma that is characterized by the selective growth of neoplastic cells in blood vessels, representing a potentially treatable cause of rapidly progressive dementia (RPD). Given its diverse clinical and instrumental presentation, it is often misdiagnosed with more common RPD causes, for example, Creutzfeldt-Jakob disease (CJD) or vascular dementia.

Methods: This study presents the clinical and histopathological characteristics of four IVLBCL cases that we diagnosed post-mortem over 20 years among over 600 brain samples received as suspected CJD cases at our prion disease reference center.

Genomic Profiling of Primary Diffuse Large B-Cell Lymphoma of the Central Nervous System Suggests Novel Potential Therapeutic Targets.

Primary diffuse large B-cell lymphoma of the primary central nervous system (CNS-DLBCL) is an aggressive disease, with dismal prognosis despite the use of high-dose methotrexate-based polychemotherapy. Our study aimed to expand the biologic profiles of CNS-DLBCL and to correlate them with clinical/imaging findings to gain diagnostic insight and possibly identify new therapeutic targets. We selected 61 CNS-DLBCL whose formalin-fixed paraffin-embedded samples were available at first diagnosis.

Lymphomas with plasmablastic features: a report of the lymphoma workshop of the 20th meeting of the European Association for Haematopathology.

Lymphomas with plasmablastic features are a heterogeneous group of aggressive and mostly uncommon neoplasms of varied aetiologies, presenting in immunocompetent individuals as well as in immunodeficiency, associated with EBV and Kaposi sarcoma virus infections, and some as progression from indolent B-cell lymphomas. They show overlapping diagnostic features and pose a differential diagnosis with other aggressive B-cell lymphomas that can downregulate the B-cell expression programme. The spectrum of rare reactive proliferations and all lymphomas defined by plasmablastic features, together with an expanding range of poorly characterised, uncommon conditions at the interface between reactive lymphoid proliferations and neoplasia submitted to the session V of the 20 European Association for Haematopathology/Society for Hematopathology lymphoma workshop are summarised and discussed in this paper.

Mediastinal large B cell lymphoma and surrounding gray areas: a report of the lymphoma workshop of the 20th meeting of the European Association for Haematopathology.

Session 3 of the 2021 European Association for Haematopathology/Society for Hematopathology Workshop focused on mediastinal large B cell lymphomas and surrounding gray areas. One half of the session was dedicated to primary mediastinal large B cell lymphoma (PMBL) and included cases with classic clinicopathologic features, as well as cases with either morphologic or immunophenotypic variation, and PMBL-like cases with primary extramediastinal disease. The role of additional immunophenotyping and/or molecular testing to aid in the diagnosis of PMBL was discussed.

The spectrum of nodular lymphocyte predominant Hodgkin lymphoma: a report of the lymphoma workshop of the 20th meeting of the European Association for Haematopathology.

Session 4 of the 2021 European Association of Haematopathology/Society for Hematopathology Workshop focused on nodular lymphocyte predominant Hodgkin lymphoma (NLPHL). First, the spectrum of immunophenotypic variations in NLPHL and the defining criteria for classic Hodgkin Lymphoma (CHL) were discussed. The added value of further immunophenotypic characterization of both tumor cells and microenvironment to support the differential diagnosis was presented.

Unmet Clinical Needs in the Management of Idiopathic Multicentric Castleman Disease: A Consensus-based Position Paper From an ad hoc Expert Panel.

Castleman disease describes a group of heterogeneous clinicopathological disorders now included in the tumor-like lesions with B-cell predominance of the World Health Organization classification. Managing idiopathic multicentric Castleman disease (iMCD) is challenging, because few systematic studies or comparative randomized clinical trials have been conducted. International, consensus evidence-based guidelines for iMCD were published in 2018, but gaps in the therapeutic options for difficult-to-treat patients, who do not respond to siltuximab and other conventional therapies, still exist.

Multicentric Castleman Disease and Concurrent Hematological Disorders: The Occurrence of Plasmacytoma and the Hypotheses Arising from Literature Review.

The concomitant presence of Castleman disease (CD) with other hematological pathology is an event described in the literature with increasing frequency, able to modify the diagnostic and curative approach in such patients. Very few studies in the literature describe the association of CD with concomitant neoplastic diseases; the most frequent are Kaposi's sarcomas (especially in HIV and human herpes virus-8-positive patients) and lymphoproliferative disorders, such as lymphomas. Instead, since the association with plasma cell diseases such as multiple myeloma and plasmacytoma is infrequent, there is a lack of literature.

Does Etelcalcetide reverse myelofibrotic bone changes due to hyperparathyroidism? A case report.

Secondary hyperparathyroidism (SHPT) in dialysis is common. A young man on chronic hemodialysis with SHPT developed pancytopenia with resistant anemia requiring transfusions. A bone marrow biopsy showed grade 3 fibrosis, depleted cellularity, osteosclerosis, and decreased myelopoiesis.