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Competing Interests: Declaration of interests We declare no competing interests.

A 4-year-old female Maltese dog was referred to our veterinary hospital with uveitis and conjunctivitis of the right eye. An ophthalmological evaluation revealed an intraocular mass that appeared to originate from the anterior uvea. Metastasis and regional invasion were not detected with CT examination. Enucleation of the right eye was recommended; however, the owner declined treatment. Six months later, the dog was re-presented with a right facial mass. At presentation, superficial lymph node enlargement was not appreciated, and no apparent alterations were noted on blood analysis or urinalysis. Computed tomography revealed an intraocular mass that invaded the surrounding tissues, including the frontal sinus. Presumed solitary ocular lymphoma with a large B-cell phenotype and Mott cell change was diagnosed via histopathological and immunohistochemical examination of a biopsy of the lesion. As the mass was too large for complete excision, neoadjuvant chemotherapy was administered. Complete remission was achieved using the L-COAP protocol and successful exenteration of the right eye. However, the dog was returned with enlargement of the right retropharyngeal lymph nodes. To the best of our knowledge, this is the first case report of presumed solitary ocular lymphoma with a large B-cell phenotype displaying Mott cell change in a dog. Key clinical message: This is the first reported case of a presumed solitary ocular lymphoma with a large B-cell phenotype and Mott cell change. Although systemic involvement was observed 6 mo after the initial visit, neoadjuvant chemotherapy and exenteration were effective., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

Primary cutaneous B-cell lymphomas represent a type of non-Hodgkin's lymphoma of the skin without evidence of extracutaneous involvement at the time of diagnosis. According to the 2018 World Health Organization-the European Organization for Research and Treatment of Cancer classification, primary cutaneous B-cell lymphomas include primary cutaneous marginal zone lymphoma, primary cutaneous follicle center lymphoma, primary cutaneous diffuse large B-cell lymphoma, leg type, intravascular large B-cell lymphoma, and Epstein-Barr virus+ mucocutaneous ulcer (provisional). Herein, we provide a comprehensive review of the updated literature on these entities, including clinical presentation, histopathology, immunophenotype, molecular genetics, prognosis, and treatment., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Previous studies in patients with mature B-cell lymphomas (MBCL) have shown that pathogenic TP53 aberrations are associated with inferior chemotherapeutic efficacy and survival outcomes. In solid malignancies, p53 immunohistochemistry is commonly used as a surrogate marker to assess TP53 mutations, but this correlation is not yet well-established in lymphomas. This study evaluated the accuracy of p53 immunohistochemistry as a surrogate marker for TP53 mutational analysis in a large real-world patient cohort of 354 MBCL patients within routine diagnostic practice. For each case, p53 IHC was assigned to one of three categories: wild type (staining 1-50% of tumor cells with variable nuclear staining), abnormal complete absence or abnormal overexpression (strong and diffuse staining > 50% of tumor cells). Pathogenic variants of TP53 were identified with a targeted next generation sequencing (tNGS) panel. Wild type p53 expression was observed in 267 cases (75.4%), complete absence in twenty cases (5.7%) and the overexpression pattern in 67 cases (18.9%). tNGS identified a pathogenic TP53 mutation in 102 patients (29%). The overall accuracy of p53 IHC was 84.5% (95% CI 80.3-88.1), with a robust specificity of 92.1% (95% CI 88.0- 95.1), but a low sensitivity of 65.7% (95% CI 55.7-74.8). These results suggest that the performance of p53 IHC is insufficient as a surrogate marker for TP53 mutations in our real-world routine diagnostic workup of MBCL patients. By using p53 immunohistochemistry alone, there is a significant risk a TP53 mutation will be missed, resulting in misevaluation of a high-risk patient. Therefore, molecular analysis is recommended in all MBCL patients, especially for further development of risk-directed therapies based on TP53 mutation status., (© 2023. The Author(s).)

Flow-cytometry (FC) is a powerful tool that can assist in lymphoma diagnosis in lymph node (LN) specimens. Although lymphoma diagnosis and classification are mainly based on tumor cell characteristics, surrounding cells are less employed in this process. We retrospectively investigated alterations in the ploidy status, proliferative cell fraction (PF) and the percentages of surrounding immune cells in 62 consecutive LN specimens with B-Cell Non-Hodgkin Lymphoma (B-NHL) that were submitted for FC evaluation between 2019-2022. Compared with indolent B-NHLs, aggressive B-NHLs show increased DNA aneuploidy and PF, increased monocytes, immature-granulocytes, mature granulocytes, CD8 + T-cells, Double-Negative-T-cells and Double-Positive-T-cells, and decreased total CD45 + cells, total lymphocytes, CD4 + T-cells and CD4/CD8 ratio. Receiver operating characteristic analysis determined PF > 6.8% and immature-granulocytes > 0.9% as optimal cutoffs with highest specificity and sensitivity in differentiating aggressive and indolent B-NHLs. These findings further strength the diagnostic value of DNA content analysis by FC and suggest the utilization of tumor surrounding immune cells in NHL diagnosis and classification., (© 2024. The Author(s).)

MYD88 p.L265P mutation occurs in over 90% of Waldenström's macroglobulinemia (WM), which is characterized by lymphoplasmacytic lymphoma (LPL) with monoclonal IgM. WM requires careful diagnosis due to overlapping features with other B-cell malignancies. Bing-Neel syndrome (BNS), a rare complication of WM, involves central nervous system (CNS) invasion. This report describes two cases of morphologically low-grade B-cell lymphoma in the bone marrow accompanied by the presence of a large B-cell lymphoma in the brain and a common MYD88 p.L265P mutation, which were eventually established as BNS mimickers. Although the two components in these cases showed the same identical light-chain restriction, different immunoglobulin heavy-chain rearrangement peaks indicated distinct lymphoma stem cells for CNS and bone marrow lesions. These clinical cases emphasize the challenges in diagnosing BNS. Based on the findings, biopsy is recommended for accurate identification of the clonal relationship and MYD88 mutation status.

Background: Splenic cysts are uncommon and very rarely malignant therefore their treatment isn't standardized. In case of symptomatic cysts different surgical approaches have been suggested. Primary malignant lymphoma of the spleen comprises less than 1% of non-Hodgkin's lymphomas. To our knowledge, only 203 cases of splenic large B-cell lymphoma (LBCL) have been reported to date and only 2 of them were fibrin-associated splenic cysts., Case Presentation: 27-year-old model with a 19 × 13 cm splenic cyst without data of malignancy in the preliminary study and therefore treated with laparoscopic deroofing. After histological diagnosis of LBCL with a fibrin/EBV-associated splenic pseudocyst, the patient received 4 cycles of Rituximab and a laparoscopic splenectomy was performed due to resurgence of the pseudocyst. No evidence of malignancy has been found during follow up (EBV viral load every 3 months during the first year, PET-CT every 6 months during the first year and annual afterwards) performed after the splenectomy., Discussion and Conclusions: The value of tumor markers and radiology for diagnosis of splenic cysts is put into question. Only 60 cases of Fibrin-associated LBCL (FA-LBCL) have been described in the literature therefore there are no treatment guidelines for them even though surgery together with systemic treatment has been the prevalent route with good results in most cases., (© 2024. The Author(s).)

Multicolor flow cytometry (MFC) is crucial in detecting occult or minimal bone marrow (BM) involvement by non-Hodgkin lymphomas (NHL), which may not be detected using trephine biopsy or imaging studies. Detection of low-level BM involvement can be challenging without definite immunophenotypic aberrancies. We studied the utility of CD305 in MFC detection of minimal BM involvement by B-NHL, especially in the absence of aberrancies by commonly used markers. The study included 1084 consecutive BM samples submitted for the staging of B-NHLs (excluding CLL) over two years. Samples were studied for morphological, immunophenotypic, and histopathological assessment. MFC studies were performed using 10-13 color MFC, including CD305-antibody (clone, DX26). Minimal BM involvement was defined with a cutoff of ≤10% lymphoma cells in viable cells on MFC assessment. Of 1084, 148 samples revealed overt morphological involvement by B-NHL and were excluded from analysis. BM samples of 172/936 patients were morphologically negative but revealed involvement using MFC independently. Corresponding trephine biopsy involvement was detected in only 79/172 (45.9%) patients. On MFC, 23/172 samples showed BM involvement with >10% lymphoma cells, and 149/172 (86.6%) samples revealed minimal involvement. In 54/149 (36.24%) samples, lymphoma cells were detected only with aberrant loss of CD305 expression. In 78 of the remaining 95 samples (82.1%), it provided an immunophenotypic aberrancy addition to other markers and supported the results. CD305 is a highly useful marker in the flow cytometric assessment of minimal BM involvement by B-NHL. MFC is a superior modality to trephine biopsy in detecting low-level BM involvement., (© 2024 The Author(s). Cytometry Part B: Clinical Cytometry published by Wiley Periodicals LLC on behalf of International Clinical Cytometry Society.)

Quadruple-hit lymphomas are extremely rare non-Hodgkin lymphomas with a reported dismal prognosis in the few reported cases. A "quadruple hit" has been defined by the presence of concurrent MYC, BCL2, BCL6, and CCND1 chromosomal rearrangements. We report a new case of a quadruple hit lymphoma in a 73-year-old Hispanic man who presented with an enlarging left-sided neck mass. Computed tomography showed a 1.9-cm mass in left the tonsil with bulky cervical lymphadenopathy. The presence of all four chromosomal rearrangements can reportedly occur with disease progression in both diffuse large B-cell lymphomas and mantle cell lymphomas. Further characterization of the tumor by next-generation sequencing may be of benefit to delineate between these two possibilities. Immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), and next-generation sequencing were used to confirm and classify the diagnosis. Histologic sections of the cervical lymph node demonstrated an atypical lymphoid infiltrate with large and pleomorphic cells, which were positive for CD20, CD10, BCL1 (Cyclin D1), BCL2, BCL6, and cMYC and negative for CD5 and SOX11 on immunohistochemistry with a Ki-67 proliferative index of 70%. FISH demonstrated MYC, BCL2, BCL6, and CCND1 rearrangements and the diagnosis of high-grade B-cell lymphoma with MYC, BCL2, BCL6, and CCND1 was rendered. Our patient was treated with dose adjusted etoposide, doxorubicin, cyclophosphamide, prednisone, and rituximab chemotherapy and has been in remission for 20 months., (© 2024. The Author(s).)

Minimal residual disease (MRD) diagnostics is of high clinical relevance in patients with indolent B-cell non-Hodgkin lymphomas (B-NHL), B-cell chronic lymphocytic leukemia (CLL), and multiple myeloma and serves as a surrogate parameter to evaluate treatment effectiveness and long-term prognosis. Real-time quantitative PCR (RQ-PCR) targeting circulating lymphoma cells is still the gold standard for MRD detection in indolent B-NHL and currently the most sensitive and the most broadly applied method in follicular lymphoma (FL) and mantle cell lymphoma (MCL). Alternatively, droplet digital PCR (ddPCR) can be used for MRD monitoring in multiple myeloma, mantle cell lymphoma, CLL, and FL with comparable sensitivity, accuracy, and reproducibility.The most broadly applicable MRD target in B-NHL is the junctional regions of the rearranged immunoglobulin heavy (IGH) and light chain genes. Complete and incomplete IGH and additionally IG kappa light chain rearrangements can be used as targets for MRD. Next-generation sequencing (NGS) of IG-rearrangements (IG-NGS) as new sequencing-based technology can overcome the limitation of PCR-based approaches and has a potential for higher sensitivity. Chromosomal translocations like the t(14;18)(q32;q21) translocation associated with IGH::BCL2 fusion in FL and t(11;14)(q13;q32) translocation in MCL leading to the IGH::CCND1 fusion can be used as MRD target in selected lymphoma subtypes. In patients with CLL, both flow-cytometry and RQ-PCR are equally suited for MRD assessment as long as a sensitivity of 10 -4 is achieved.MRD diagnostics targeting the IG loci is complex and requires extensive knowledge and experience because the junctional regions of each clonal rearranged gene have to be identified before the patient-specific PCR assays can be designed for MRD monitoring. In addition, the presence and load of somatic hypermutation within the rearranged IGH gene occurring during B-cell development of germinal center and post-germinal center B-cell lymphomas may hamper appropriate primer binding leading to false-negative results. The translocations mentioned above have the advantage that consensus forward primers and probes, both placed in the breakpoint regions of chromosome 18 in FL and chromosome 11 in MCL, can be used in combination with a reverse primer placed in the IGH joining region of chromosome 14. PCR-based methods using allele-specific primers can reach a high sensitivity of up to 10 -5 . This chapter provides all relevant background information and technical aspects for the complete laboratory process from detection of the clonal IG gene rearrangements and the chromosomal translocations at diagnosis to the actual MRD measurements in clinical follow-up samples of B-NHL. However, it should be noted that MRD diagnostics for clinical treatment protocols has to be accompanied by regular international quality control rounds to ensure the reproducibility and reliability of the MRD results. This is available by the EuroMRD network ( https://euromrd.org ), a subgroup of ESHLO ( https://eslho.org )., (© 2025. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Lymphoma is the most common tumor of hematopoietic origin in horses. The course of the disease and clinical signs vary greatly, depending on tumor location and extent. The aim of this report is to describe the occurrence of T-cell-rich oral large B-cell lymphoma with marked local infiltration in a 25-year-old Crioula mare. The mare showed an increase in volume on the right side of its face, dyspnea, anorexia, and progressive weight loss. The clinical assessment showed that the lesion was located in the rostral and caudal sinuses and was markedly invasive to adjacent structures. The autopsy revealed a yellow mass with a soft to firm consistency, infiltrating multiple bones in the skull, and extensively invading the hard palate and masseter muscle. Histologically the mass comprised an undifferentiated malignant neoplasm characterized by a densely cellular neoplasm composed of large CD20 + neoplastic B-lymphocytes admixed with sheets of small, CD3 + reactive T-lymphocytes supported by delicate fibrovascular stroma leading to the diagnosis of oral T-cell-rich large B-cell lymphoma., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

This MIB guide briefly summarizes the generation of patient-derived xenografts (PDXs) and highlights the importance of validating PDX models for the presence of B cell lymphoma of human origin before their use in radiotheranostic applications. The use of this protocol will allow researchers to learn different methods for screening PDX models for Epstein-Barr virus (EBV)-infected B cell lymphoma., (© 2024. The Author(s), under exclusive licence to World Molecular Imaging Society.)

We describe the first reported case of granulomatosis polyangiitis (GPA)-associated sclerokeratitis in a patient with treated ocular adnexal lymphoma (OAL). The patient presented with pain and decreased vision in the left eye over several weeks. Past medical history was significant for recent bilateral relapsing OAL that was treated successfully with radiotherapy. Examination of the eyes revealed sectoral scleritis and peripheral ulcerative keratitis. Magnetic resonance imaging (MRI) of the orbits excluded recurrence of OAL and serum antineutrophil cytoplasmic autoantibody (ANCA) titres confirmed the diagnosis of GPA. Disease was poorly responsive to systemic steroids, azathioprine and rituximab. Ultimately, resolution was achieved with successive subconjunctival dexamethasone and subconjunctival triamcinolone injections. This case highlights the need to consider ocular inflammation in patients with a history of malignant hemopathies.

Background: The NFLymSI-18 is a patient-reported outcome measure comprised of the highest priority symptoms, emotional concerns, treatment side effects, and other concerns identified by lymphoma patients and oncologists. This study assessed the content validity of the NFLymSI-18 for patients with indolent B-cell non-Hodgkin's lymphoma (iNHL), with a focus on the Disease-Related Symptoms Physical (DRS-P) subscale., Methods: Patients with a confirmed iNHL diagnosis who had received one or more lines of treatment were recruited during clinic visits. Patients described their symptoms, treatment side effects, and emotional concerns related to iNHL in a semi-structured interview. Qualitative data were analyzed using NVivo10., Results: Data saturation was obtained by the 18th interview. Most participants (67%) had follicular lymphoma. 28% of participants had marginal zone lymphoma, and one participant had lymphoplasmacytoid lymphoma/Waldenström macroglobulinemia. Mean age of the 18 participants was 67 years. 56% of the sample was male. Most participants (67%) had a college or advanced degree. When asked to describe their iNHL symptoms, patients most often discussed swelling (n = 14), fatigue (n = 11), and pain (n = 8). The following symptoms were mentioned by three patients each: anxiety, appetite loss, rash, sleep disruption, trouble breathing, and malaise. Mapping of NFLymSI-18 content to these concerns showed the instrument includes all those most frequently mentioned symptoms., Conclusions: This study supports the content validity of the NFLymSI-18, including its DRS-P Subscale, for patients with iNHL. The instrument shows strong validity for the most referenced symptoms of swelling, fatigue, and pain. The diversity of additional symptoms reported by patients is consistent with the heterogeneous symptomology of iNHL., (© 2024. The Author(s).)

Evaluation of B-cell clonality can be challenging in the interpretation of lymphoid infiltrates on tissue sections. Clonality testing based on IG gene rearrangements analysis by PCR (IG-PCR) is the gold standard. Alternatively, B-cell clonality can be assessed by the recognition of immunoglobulin light chain (IgLC) restriction, by immunohistochemistry (IHC), chromogenic in situ hybridization (ISH) or flow cytometry (FC). IG-PCR requires molecular facilities, and FC requires cell suspensions, both not widely available in routine pathology units. This study evaluates the performance of B-cell clonality detection by IgLC-RNAscope® (RNAsc) in a group of 216 formalin-fixed, paraffin-embedded samples including 185 non-Hodgkin B-cell lymphomas, 11 Hodgkin lymphomas (HL) and 20 reactive samples. IgLC-RNAsc, performed in parallel with FC in 53 cases, demonstrated better performances (93% vs 83%), particularly in diffuse large B-cell lymphoma (98% vs 71%) and follicular lymphoma (93% vs 83%) diagnosis. IgLC-RNAsc was also superior to IHC and ISH especially in samples with limited tumor cell content, where IG-PCR was not informative. Performed for the first time on mediastinal lymphomas, IgLC-RNAsc identified monotypic IgLC transcripts in 69% of primary mediastinal large B-cell lymphoma (PMBCL) and 67% of mediastinal gray zone lymphomas (MGZL). IGK/L double-negative cells were detected in 1 PMBCL, 2 MGZL, and all classical HL, while monotypic IgLC expression appeared to be a hallmark in nodular lymphocyte-predominant HL. IgLC-RNAsc demonstrates to be a powerful tool in B-cell lymphoma diagnosis, above all in challenging cases with limited tumor cell content, ensuring in situ investigations on mechanisms of Ig regulation across lymphoma entities., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Multiparameter flow cytometry data is visually inspected by expert personnel as part of standard clinical disease diagnosis practice. This is a demanding and costly process, and recent research has demonstrated that it is possible to utilize artificial intelligence (AI) algorithms to assist in the interpretive process. Here we report our examination of three previously published machine learning methods for classification of flow cytometry data and apply these to a B-cell neoplasm dataset to obtain predicted disease subtypes. Each of the examined methods classifies samples according to specific disease categories using ungated flow cytometry data. We compare and contrast the three algorithms with respect to their architectures, and we report the multiclass classification accuracies and relative required computation times. Despite different architectures, two of the methods, flowCat and EnsembleCNN, had similarly good accuracies with relatively fast computational times. We note a speed advantage for EnsembleCNN, particularly in the case of addition of training data and retraining of the classifier., (© 2024 International Clinical Cytometry Society.)

Vitreoretinal lymphoma (VRL) is a rare B-cell intraocular neoplasia characterized by poor long-term prognosis and lack of effective therapies. It mainly involves the vitreous humor, the retina, and the retinal pigment epithelium (RPE), although anterior segment involvement can occur. VRL is classified as a lymphoma of immune privileged sites, along with testis lymphoma and primary central nervous system lymphoma (PCNSL). VRL and PCNSL are strictly connected indeed: 80% of VRL develop PCNSL, while 20% of patients with PCNSL present VRL during natural history of lymphoma. Due to the lack of worldwide consensus about diagnosis, therapy, and follow-up timing, VRL represents one of the most challenging ocular affections.VRL commonly masquerades as a posterior uveitis, and misdiagnosis often occurs because of partial response to topical steroids. Gold standard for diagnosis is cytological analysis of vitreous humor. However, this technique lacks sensitivity and supplemental molecular analyses can improve the diagnostic process. Multimodal imaging allows ophthalmologists to empower their clinical suspicion and a comprehensive examination can highlight typical features of VRL and justify further invasive procedures.There is no consensus about VRL therapy, and none of the therapeutical scheme has demonstrated to prevent cerebral involvement and improve patient's overall survival. Intravitreal injections of chemotherapeutics drugs, ocular radiation therapy and systemic chemotherapy can be considered in the treatment of VRL. Once cerebral involvement occurs, systemic chemotherapy must be included in the treatment as a life-saving therapy. Further multicentric studies are required to find out the best treatment of patients with VRL.

Despite excellent cure rates among children, adolescents, and young adults (CAYAs) with mature B-cell non-Hodgkin lymphomas (B-NHLs) treated with chemoimmunotherapy, CAYAs with relapsed/refractory B-NHL remain difficult to treat, with a dismal prognosis. Reinduction and subsequent therapeutic management are not standardized. The armamentarium of active agents against B-NHL, including antibody-drug conjugates, monoclonal antibodies, checkpoint inhibitors, T-cell engagers, CAR T cells, CAR-natural killer (CAR-NK) cells, and cell signaling inhibitors, continues to expand. This article reviews current management practices and novel therapies in this difficult to treat population.

Objective: To compare the consistency of lymphoma multigene detection panels based on next-generation sequencing (NGS) with FISH detection of B-cell lymphoma gene rearrangement. Methods: From January 2019 to May 2023, fusion genes detected by lymphoma-related 413 genes that targeted capture sequencing of 489 B-cell lymphoma tissues embedded in paraffin were collected from Henan Cancer Hospital, and the results were compared with simultaneous FISH detection of four break/fusion genes: BCL2, BCL6, MYC, and CCND1. Consistency was defined as both methods yielding positive or negative results for the same sample. The relationship between fusion mutation abundance in NGS and the positivity rate of cells in FISH was also analyzed. Results: Kappa consistency analysis revealed high consistency between NGS and FISH in detecting the four B-cell lymphoma-related gene rearrangement ( P <0.001 for all) ; however, the detection rates of positive individuals differed for the four genes. Compared with FISH, NGS demonstrated a higher detection rate for BCL2 rearrangement, a lower detection rate for BCL6 and MYC rearrangement, and a similar detection rate for CCND1 rearrangement. No correlation was found between fusion mutation abundance in NGS and the positivity rate of cells in FISH. Conclusions: NGS and FISH detection of B-cell lymphoma gene rearrangement demonstrate overall good consistency. NGS is superior to FISH in detecting BCL2 rearrangement, inferior in detecting MYC rearrangement, and comparable in detecting CCND1 rearrangement.

Background: The diagnosis of B-cell lymphoma, one of the commonest cancers seen in childhood and adolescence, is challenging. There is a crucial need to identify and delineate the prevalence of associated symptoms in order to improve early diagnosis., Aims: To identify clinical presentations associated with childhood and adolescent B-cell lymphomas and estimate symptom prevalence., Methods: A systematic review of observational studies and meta-analysis of proportions was carried out. Medline and EMBASE were systematically searched, with no language restrictions, from inception to 1st August 2022. Observational studies with at least 10 participants, exploring clinical presentations of any childhood and adolescent lymphoma, were selected. Proportions from each study were inputted to determine the weighted average (pooled) proportion, through random-effects meta-analysis., Results: Studies reported on symptoms, signs and presentation sites at diagnosis of 12,207 children and adolescents up to the age of 20. Hodgkin's lymphoma most frequently presented with adenopathy in the head-and-neck region (79% [95% CI 58%-91%]), whilst non-Hodgkin's lymphoma presented abdominally (55% [95% CI 43%-68%]). Symptoms associated with lymphoma included cervical lymphadenopathy (48% [95% CI 20%-77%]), peripheral lymphadenopathy (51% [95% CI 37%-66%]), B-symptoms (40% [95% CI 34%-44%]), fever (43% [95% CI 34%-54%]), abdominal mass (46% [95% CI 29%-64%]), weight loss (53% [95% CI 39%-66%]), head-and-neck mass (21% [95% CI 6%-47%]), organomegaly (29% [95% CI 23%-37%]), night sweats (19% [95% CI 10%-32%]), abdominal pain (28% [95% CI 15%-47%]), bone pain (17% [95% CI 10%-28%]) and abnormal neurology (11% [95% CI 3%-28%])., Conclusion: This systematic review and meta-analysis of proportions provides insight into the heterogeneous clinical presentations of B-cell lymphoma in childhood and adolescence and provides estimates of symptom prevalence. This information is likely to increase public and clinical awareness of lymphoma presentations and aid earlier diagnosis. This review further highlights the lack of studies exploring childhood and adolescent lymphoma presentations in primary care, where patients are likely to present at the earliest stages of their disease., (© 2024. The Author(s).)

Introduction: Primary central nervous system lymphoma (PCNSL) presents a diagnostic enigma due to the inherent absence of lymphoid tissue in the central nervous system (CNS). The hypothesis posits that lymphocytes infiltrating the CNS during inflammatory responses could represent a cellular source for PCNSL, challenging traditional understandings of its etiology., Patient Concerns: In 2 illustrative cases, patients presented with neurological symptoms initially misdiagnosed as encephalitis and demyelinating disease, respectively. These diagnoses were established based on clinical assessments and initial biopsy findings., Diagnosis: Subsequent biopsies, conducted months after the first signs of disease, confirmed the diagnosis of PCNSL in both patients. Identifying CD20-positive tumor cells was pivotal, indicating a B-cell lymphoma origin., Interventions: Treatment strategies included high-dose methotrexate chemotherapy for both patients. In addition, the second patient underwent adjuvant whole-brain radiotherapy after the chemotherapy regimen., Outcomes: The therapeutic approach significantly reduced tumor size in both cases, with no evidence of recurrence observed during the follow-up period. This outcome underscores the potential efficacy of the chosen interventions., Conclusion: In response to inflammatory lesions, lymphocyte infiltration into the CNS may serve as a pivotal origin for tumor cells in PCNSL. These cases highlight the complexity of diagnosing CNS disorders and suggest that various forms of encephalitis in the early stages could influence the prognosis of lymphoma. This insight into the cellular origins and treatment responses of PCNSL contributes to a broader understanding of its pathophysiology and management., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 by Mutaz B. Habal, MD.)

In the 1980s, immunohistochemistry and clonality analyses became instrumental in the recognition and definition of new types of cutaneous T-cell lymphoma (CTCL) and cutaneous B-cell lymphoma (CBCL) and the development of new classifications. By accepting loss of pan-T-cell antigens and clonal T-cell receptor gene rearrangements as important criteria to differentiate between benign and malignant T-cell proliferations, and monotypic immunoglobulin light-chain expression and clonal immunoglobulin gene rearrangements as crucial criteria to distinguish between benign and malignant B-cell proliferations, many cases, until then diagnosed as cutaneous lymphoid hyperplasia or pseudolymphoma, were reclassified as primary cutaneous CD4+ small/medium T-cell lymphoma (PCSM-TCL) or primary cutaneous marginal zone lymphoma (PCMZL), respectively. However, in recent years there is growing awareness that neither these immunohistochemical criteria nor demonstration of T-cell or B-cell clonality is specific for malignant lymphomas. In addition, many studies have reported that these low-grade malignant CTCL and CBCL have an indolent clinical behavior and an excellent prognosis with disease-specific survival rates of or close to 100%. As a result, recent classifications have downgraded several low-grade malignant cutaneous lymphomas to lymphoproliferative disorder (LPD). Both the 5th edition of the WHO classification (2022) and the 2022 International Consensus Classification (ICC) of mature lymphoid neoplasms reclassified PCSM-TCL as primary cutaneous CD4+ small/medium T-cell LPD and primary cutaneous acral CD8+ T-cell lymphoma as primary cutaneous acral CD8+ T cell LPD. While the 2022 ICC introduced the term "primary cutaneous marginal zone LPD," in the 5th edition of the WHO classification PCMZL is maintained. In this review we describe the background and rationale of the continually changing terminology of these conditions and discuss the clinical consequences of downgrading malignant lymphomas to LPDs., (© 2024 The Authors. Journal of Cutaneous Pathology published by John Wiley & Sons Ltd.)

B-cell lymphomas occur with an incidence of 20 new cases per 100 000 people per year in high-income countries. They can affect any organ and are characterised by heterogeneous clinical presentations and courses, varying from asymptomatic, to indolent, to very aggressive cases. Since the topic of B-cell non-Hodgkin lymphomas was last reviewed in The Lancet in 2017, a deeper understanding of the biological background of this heterogeneous group of malignancies, the availability of new diagnostic methods, and the development and implementation of new targeted and immunotherapeutic approaches have improved our ability to treat patients. This Seminar provides an overview of the pathobiology, classification, and prognostication of B-cell non-Hodgkin lymphomas and summarises the current knowledge and standard of care regarding biology and clinical management of the most common subtypes of mature B-cell non-Hodgkin lymphomas. It also highlights new findings in deciphering the molecular background of disease development and the implementation of new therapeutic approaches, particularly those targeting the immune system., Competing Interests: Declaration of interests GS has received financial compensations for participating on advisory boards and consulting from AbbVie, Beigene, Bristol Myers Squibb, Epizyme, Roche, Genmab, Incyte, Janssen, Gilead, Loxo, Miltenyi, Molecular Partners, Morphosys, Nordic Nanovector, Novartis, Rapt, Takeda, Debiopharm, Ipsen, and Merck; has received hororaria from AbbVie, Bayer, Incyte, Gilead, Morphosys, Novartis, and Regeneron; and is shareholder at Owkin. EC has been a consultant for Takeda, NanoString Technologies, and Illumina; has received honoraria from EusPharma, Takeda, and Janssen for speaking at educational events; and is an inventor on a Lymphoma and Leukaemia Molecular Profiling Project patent (PCT/US2014/064161). MD has received research support from AbbVie, Bayer, Bristol Myers Squibb, Gilead, Janssen, and Roche; has received financial compensation for participating at advisory boards from AstraZeneca, Beigene, Bristol Myers Squibb, Gilead, Janssen, Lilly, Novartis, and Roche; and has received honoraria from Amgen, AstraZeneca, Gilead, Janssen, Lilly, Novartis, and Roche. ES declares no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.)

A 72-year-old male was referred with a 2-week history of diplopia. Following magnetic resonance imaging, an area of abnormal signal intensity was observed along the lateral ventricle, without any unusual findings at other sites. Cerebrospinal fluid cytology revealed abnormal lymphocytes with atypia, which were positive for CD20 and light-chain restriction, as detected by surface marker analysis, leading to a diagnosis of primary meningeal B-cell lymphoma. The patient underwent chemoradiotherapy and achieved a remission. While meningeal lymphoma is a rare occurrence, pathological tissue biopsy is considered the gold-standard diagnostic method. However, obtaining a biopsy sample from the tumor site can be challenging. In this case report, cytology and flow cytometry played a vital role in the diagnosis of meningeal lymphoma.

Context: Pathologists play an increasingly critical role in optimizing testing on scant specimens to ensure patients not only receive a correct and timely diagnosis, but also that the appropriate evaluation of biologic markers, or "biomarkers," is performed to inform prognosis and best guide therapeutic options. Advances in biomarkers have been particularly impactful in the field of hematopathology, where the identification of cytogenetic abnormalities, specific mutations, morphologic features, and/or protein expression may help guide clinical decision-making, including type and intensity of therapy and eligibility for clinical trials., Objective: To stay up to date with advances in relevant biomarkers for diagnosis, prognosis, and therapy. The Cancer Biomarkers Conference (CBC) has been developed as a highly focused meeting to provide key biomarker updates across medical fields with the inclusion of industry partners, to reach a broader audience, and cross-pollinate emerging areas for biomarker application and future discovery. The objective of this article is to raise awareness of the potential utility of such meetings for improving patient care and facilitating collaboration., Data Sources: Recently released guidelines related to B-cell lymphoma diagnosis from the World Health Organization and International Consensus Classification and associated manuscripts are reviewed. Material presented at the CBC conference is summarized., Conclusions: This article covers highlights of the updates presented on B-cell lymphoma biomarkers at the most recent Cancer Biomarkers Conference in Flowood, Mississippi, in September 2022., Competing Interests: The author has no relevant financial interest in the products or companies described in this article., (© 2024 College of American Pathologists.)

Cerebrospinal fluid (CSF) involvement in B cell non-Hodgkin lymphomas is a poor prognostic sign and diagnosis is made using techniques such as flow cytometry (FCM) and conventional cytology (CC)., Aim: To evaluate the frequency of CSF involvement in B-NHL by both techniques in a public hospital., Material and Methods: 97 CSF samples were analyzed in tubes with cell preservative belonging to 70 patients, 71% male, median age 56 years (18-85 years), with a diagnosis of B-NHL and risk of infiltration according to medical criteria. Most were patients from new diagnosis (89%), diffuse large B cell lymphoma (60%), and Ann-Arbor stage III-IV (77%). In 67 samples (69%), CC and CMF were performed simultaneously., Results: Of the samples analyzed by CMF, 99% were valuable, while by CC, only 67% (p<0,05). Globally, 25% of the samples showed infiltration by CMF, while 18% by CC (p<0,0001). Forty-four valuable samples were evaluable and analyzed by CC and CMF, finding a similar frequency of positive cases (27%), with two-thirds positive only by CC or CMF. Positive samples in diffuse large B cell lymphoma were 28% by CC and/or CMF., Conclusions: A higher proportion of infiltration cases were detected by CMF than by CC. In valuable cases, CC complements CMF.

Background: Canine lymphoma is the most common hematopoietic cancer in dogs. Numerous studies have evaluated the prognostic value of hematological abnormalities and ratios in both humans and dogs with lymphoma., Aim: To compare hematological parameters and complete blood count ratios between a population of dogs affected by lymphoma and healthy dogs to identify potential prognostic markers for lymphoma., Methods: This retrospective case-control study compares hematological parameters and complete blood count ratios between a population of 114 dogs affected by multicentric large B-cell lymphoma (LBCL) and 60 healthy dogs., Results: The study found several statistically significant differences between the hematological indices of LBCL dogs and healthy dogs, but no correlation between these parameters and the survival times of 78 dogs treated with chemotherapy Madison Wisconsin protocol. In addition, hematological alterations were evaluated such as anemia, leukocytosis, and thrombocytopenia., Conclusion: Hematological ratios have been suggested as potential prognostic markers for canine LBCL but their real prognostic value remains controversial and requires future investigation., Competing Interests: The authors declare that there is no conflict of interest.

Peritoneal lymphomatosis (PL) is a rare lymphoma-associated condition defined as the dissemination of lymphoma cells in the peritoneum. An 82-year-old man presented with abdominal pain, heartburn, and high fever. Radiological findings, including positron emission tomography-computed tomography (PET-CT), and gastrointestinal fiberscopy, showed diffuse thickening of the peritoneum, omentum, and mesentery; however, no lymphadenopathy, hepatosplenomegaly, or gastrointestinal lesions were observed. Under suspicion of peritonitis carcinomatosa of unknown origin, exploratory laparoscopy was performed that revealed multiple white nodules and masses on the surfaces of the peritoneum, mesentery, and intestinal serosa. The histopathological and cytogenetic findings of the peritoneum revealed high-grade B-cell lymphoma, not otherwise specified, and a gain of MYC by fluorescence in-situ hybridization. The patient was treated with two cycles of R-CHOP therapy, followed by six cycles of dose-adjusted EPOCH-R therapy, and a complete metabolic response was confirmed by PET-CT. Since there are no specific radiological findings to confirm the diagnosis of PL, a histopathological diagnosis is usually required. Most PL exhibit an aggressive lymphoma phenotype and can be cured by appropriate chemotherapy. Therefore, early diagnosis and treatment are desirable.

B-lymphoblastic leukemia/lymphoma (B-ALL/LBL) is a precursor B-cell neoplasm that often harbors specific cytogenetic/molecular abnormalities with distinctive clinical, phenotypic, and prognostic characteristics. Subcategorization of B-ALL/LBL therefore requires extensive cytogenetic and/or molecular testing to determine the appropriate classification and therapeutic interventions for these patients. Herein, we present a case of a 17-year-old young woman diagnosed with B-LBL harboring not only an IGH::MYC rearrangement but also BCL2 and BCL6 rearrangements (so-called "triple-hit") and somatic biallelic TP53 inactivation. MYC rearrangements are relatively rare in B-ALL/LBL, and the identification of a "triple-hit" elicited an initial diagnostic dilemma. However, a multimodal approach allowed for the classification of this complex case and helped guide selection of an appropriate therapeutic regimen., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Recent advances in molecular diagnostics have markedly expanded our understanding of the genetic underpinnings of lymphomas and catalysed a transformation in not just how we classify lymphomas, but also how we treat, target, and monitor affected patients. Reflecting these advances, the World Health Organization Classification, International Consensus Classification, and National Comprehensive Cancer Network guidelines were recently updated to better integrate these molecular insights into clinical practice. We summarise here the molecular biomarkers of lymphomas with an emphasis on biomarkers that have well-supported prognostic and predictive utility, as well as emerging biomarkers that show promise for clinical practice. These biomarkers include: (1) diagnostic entity-defining genetic abnormalities [e.g., B-cell acute lymphoblastic leukaemia (B-ALL) with KMT2A rearrangement]; (2) molecular alterations that guide patients' prognoses (e.g., TP53 loss frequently conferring worse prognosis); (3) mutations that serve as the targets of, and often a source of acquired resistance to, small molecular inhibitors (e.g., ABL1 tyrosine kinase inhibitors for B-ALL BCR::ABL1, hindered by ABL1 kinase domain resistance mutations); (4) the growing incorporation of molecular measurable residual disease (MRD) in the management of lymphoma patients (e.g., molecular complete response and sequencing MRD-negative criteria in multiple myeloma). Altogether, our review spans the spectrum of lymphoma types, from the genetically defined subclasses of precursor B-cell lymphomas to the highly heterogeneous categories of small and large cell mature B-cell lymphomas, Hodgkin lymphomas, plasma cell neoplasms, and T/NK-cell lymphomas, and provides an expansive summary of our current understanding of their molecular pathology., (Copyright © 2024 Royal College of Pathologists of Australasia. Published by Elsevier B.V. All rights reserved.)

Background: Assessment of bone marrow involvement (BMI) in non-Hodgkin lymphoma (NHL) is crucial for determining patient prognosis and treatment strategy. We assessed the prognostic value of next-generation sequencing (NGS)-based immunoglobulin (Ig) gene clonality analysis as an ancillary test for BMI evaluation in NHL., Methods: A retrospective cohort of 124 patients newly diagnosed with B-cell NHL between 2019 and 2022 was included. NGS-based Ig clonality analysis was conducted using LymphoTrak IGH FR1 Assay and IGK Assay (Invivoscribe Technologies, San Diego, CA, USA) on BM aspirate samples, and the results were compared with those of histopathological BMI (hBMI)., Results: Among the 124 patients, hBMI was detected in 16.9% (n = 21). The overall agreement of BMI between Ig clonality analyses and histopathological analysis for IGH, IGK, and either IGH or IGK was 86.3%, 92.7%, and 90.3%. The highest positive percent agreement was observed with clonal rearrangements of either IGH or IGK gene (90.5%), while the highest negative percent agreement was observed with clonal rearrangement of IGK gene (96.1%). For the prediction of hBMI, positive prediction value ranged between 59.1% and 80.0% and the negative prediction value ranged between 91.3% and 97.9%., Conclusion: NGS-based clonality analysis is an analytic platform with a substantial overall agreement with histopathological analysis. Assessment of both IGH and IGK genes for the clonal rearrangement analysis could be considered for the optimal diagnostic performance of BMI detection in B-cell NHL., (© 2024 The Authors. Journal of Clinical Laboratory Analysis published by Wiley Periodicals LLC.)

A 7-year-old Icelandic gelding was presented with acute severe dyspnea of one day duration and purulent nasal discharge that had been present for 6 weeks. Clinically, the initial examination focused on severe enlargement of the mandibular and retropharyngeal lymph nodes as well as a mixed dyspnea.The diagnosis of a malignant lymphoma was evident following laboratory diagnostics, endoscopy, and cytological examination of a fine needle aspiration of a mandibular lymph node. The gelding was euthanized due to the poor prognosis and a significantly disturbed general condition. Pathohistological examination revealed a multicentric T-cell-rich B-cell lymphoma., Competing Interests: Die Autoren bestätigen, dass kein Interessenkonflikt besteht., (Thieme. All rights reserved.)

The 5th edition WHO classification of B-cell tumors is a systematic update to the fourth revised version of the classification. The changes include updated names of entities, sharpened diagnostic criteria, and upgrades from provisional to definite entities. This review focuses on the changes in the content of each chapter of B-cell tumors, facilitating domestic colleagues engaged in the diagnosis and treatment of lymphohematopoietic tumors to understand the latest progress and guide daily work.

Primary cutaneous B-cell lymphomas (PCBCLs) are lymphoproliferative disorders that appear on the skin without evidence of extracutaneous manifestations at the time of diagnosis. There is a lack of evidence-based guidelines for their clinical management due to the availability of very few large scale studies and controlled clinical trials. Here we present and discuss a series of major unmet clinical needs (UCNs) in the management of PCBCLs by a panel of 16 experts involved in research and clinical practice of PCBCL. The Panel produced recommendations on the appropriateness of the clinical decisions concerning the identified clinical needs and proposed research for improving the knowledge needed to solve them. Recommendations and proposals were achieved by multiple-step formalized procedures to reach a consensus after a comprehensive analysis of the scientific literature. Recommendations and proposals lay in the domain of classification uncertainties of PCBCL, optimization of diagnosis, optimization of prognosis, optimization of staging and critical issues on therapeutic strategies with particular focus on new treatments. These recommendations are intended for use not only by experts but above all by dermatologists and hematologists with limited experience in the field of PCBCLs as well as general practitioners., (© 2023 John Wiley & Sons Ltd.)

Primary pancreatic lymphomas (PPLs) are a subgroup of gastrointestinal (GI) lymphomas. They are an exceedingly rare entity, both in terms of pancreatic malignancies and also extranodal lymphomas. Epidemiological investigations have been challenging to do because of their rarity. This has resulted in a lack of clarity on the clinicopathological characteristics, differential diagnosis, best course of treatment, and prognosis of PPL. Because the clinical signs are frequently non-specific, it can lead to a diagnostic hazard for the unwary physician. Preoperatively, it is imperative to distinguish between adenocarcinoma and PPL, as they present similarly, but have vastly different treatment modalities and prognosis. We herein present a case of an elderly man who presented with obstructive jaundice and was found to have PPL., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Mature B-cell acute lymphoblastic leukemia (ALL) is defined by the expression of light chain-restricted surface immunoglobulin (sIg) and usually has features of the leukemic phase of Burkitt lymphoma including FAB-L3 morphology and MYC rearrangement. Recently, another distinct entity in childhood mature B-cell ALL has been characterized as non-L3 morphology and KMT2A rearrangement. Here we report an unusual case of mature B-cell ALL that presented with RUNX1 rearrangement. A 65-year-old male was admitted to our department for thorough examination of leukocytosis and thrombocytopenia. The patient's bone marrow was hypercellular and infiltrated with 97.8% myeloperoxidase-negative, medium-to-large-sized blasts without cytoplasmic vacuoles. Immunophenotypes were characterized by the presence of light chain-restricted sIg and the lack of immature markers, indicating a diagnosis of mature B-cell ALL with L2 morphology: sIg-κ+, CD19+, CD20+, CD22+, CD79a+, TdT-, and CD34-. G-banding combined with spectral karyotyping showed the following complex karyotype: 45,X,der(Y;10)(p10;q10),del(13)(q?),inv(21)(p13q22.1). Fluorescence in situ hybridization revealed separated signals of RUNX1 at 21q22.1, whereas rearrangements of MYC and KMT2A were not found. To our knowledge, inv(21)(p13q22.1) involving RUNX1 is a novel cytogenetic aberration and this is the first case of mature B-cell ALL that presented with RUNX1 rearrangement. Thus, RUNX1 may be implicated in the pathogenesis of mature B-cell ALL showing non-L3 morphology without MYC rearrangement.

For the routine diagnosis of haematological neoplasms an integrative approach is used considering the morphology, and the immunophenotypic, and molecular features of the tumor sample, along with clinical information. The identification and characterization of recurrent chromosomal aberrations mainly detected by conventional and molecular cytogenetics in the tumor cells has a major impact on the classification of lymphoid neoplasms. Some of the B-cell non-Hodgkin lymphomas are characterized by particular chromosomal aberrations, highlighting the relevance of conventional and molecular cytogenetic studies in their diagnosis and prognosis. In the current genomics era, next generation sequencing provides relevant information as the mutational profiles of haematological malignancies, improving their classification and also the clinical management of the patients. In addition, other new technologies have emerged recently, such as the optical genome mapping, which can overcome some of the limitations of conventional and molecular cytogenetics and may become more widely used in the cytogenetic laboratories in the upcoming years. Moreover, epigenetic alterations may complement genetic changes for a deeper understanding of the pathogenesis underlying B-cell neoplasms and a more precise risk-based patient stratification. Overall, here we describe the current state of the genomic data integrating chromosomal rearrangements, copy number alterations, and somatic variants, as well as a succinct overview of epigenomic changes, which altogether constitute a comprehensive diagnostic approach in B-cell non-Hodgkin lymphomas., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: To investigate the expression level and the diagnostic value of serum free light chain in B-cell non-Hodgkin's lymphoma (B-NHL)., Methods: We retrospectively analyzed the results of serum free light chain (sFLC) of 394 newly treated B-NHL patients in our hospital from January 2014 to December 2021 and compared the secretion levels of sFLC among different subtypes of B-NHL. The value of sFLC secretion levels in the diagnosis of WM was evaluated using ROC., Results: Increased proportion of sFLC, abnormal ratio of sFLC (κ / λ) and the secretion levels of sFLC (κ+λ) were different in different B-NHL subtypes, Waldenstrom's macroglobulinemia (WM) had the highest proportion of elevated sFLC(82.68%) and abnormal sFLC(κ/ λ)(87.0%), the proportion of FL(18.0%) and DLBCL patients(12.8%) with elevated sFLC was lower ( P <0.05). The expression levels of sFLC can helpful in the diagnosis of WM (AUC=0.874， P <0.001， 95% CI : 0.779-0.970). At the same time, higher sFLC levels and sFLC cloning patterns predicted the possibility of bone marrow infiltration of lymphoma., Conclusion: The serum free light chains is common in patients with B-NHL. The elevated level and type of free light chain are associated with the type of lymphoma, and the patients with bone marrow infiltration have higher sFLC（κ+ λ） expression level.

Competing Interests: The authors declare that they have no conflict of interest.