Abstract Background Clinical scores incompletely capture outcomes in primary central nervous system lymphoma (PCNSL). We quantified morphologic heterogeneity in pretreatment hematoxylin and eosin (H&E) whole slides. Patients and methods Three independent cohorts of immunocompetent, HIV- and EBV-negative patients treated recently were analyzed: LOC 2023 (122 slides), phase III BLOCAGE-01 (245 slides; NCT02313389 ), and external Barcelona (BCN; 41 slides). UNI embeddings, prototype learning, spatial metrics, and elastic-net Cox regression defined ITH-C. Results Models achieved bootstrap-corrected concordance of 0.797–0.834. Age-, sex-, and KPS-adjusted ITH-C HRs were 1.29 (95% CI 1.01–1.64), 1.27 (1.07–1.51), and 2.13 (1.35–3.37), respectively. Adding ITH-C increased MSKCC C-index from 0.671 to 0.717, 0.560 to 0.593, and 0.588 to 0.706. Spatial transcriptomics linked ITH-C to immune programs. Conclusions Routine H&E encodes prognostic spatial heterogeneity in PCNSL. ITH-C complements clinical scores, supporting prospective risk stratification.

Follicular lymphoma (FL) spans both nodal and extranodal sites, with molecular characteristics that may vary by anatomical location. While nodal FL typically shows BCL2 rearrangement and frequent chromatin-modifying gene mutations (CREBBP, KMT2D), some extranodal FLs lack t(14;18)(q32:q21) and harbour distinct alterations, such as TNFRSF14 mutations. In our retrospective series of 23 ocular adnexal FL (OA FL) cases that include both primary and secondary involvement, an approximately equal distribution of BCL2-rearranged and non-rearranged cases was observed, underlining that the ocular localisation displays features of both conventional nodal and extranodal FL. Mutational analysis revealed a mix of mutations commonly seen in nodal and extranodal FL, with strong CD23 expression correlating with JAK/STAT pathway gene mutations. Most OA FLs followed an indolent course with good outcomes after local therapy, though transformation to diffuse large B-cell lymphoma occurred in a subset of two cases. Our results suggest that OA FL exhibits genetic heterogeneity, combining molecular features from both subtypes, and highlight the importance of thorough staging and individualised therapeutic and surveillance strategies for each patient.

In recent classifications several cutaneous lymphomas were reclassified as lymphoproliferative disorder (LPDs). These include primary cutaneous CD4+ small/medium T-cell LPD (PCSM-TCLPD), primary cutaneous acral CD8+ T-cell LPD (acral CD8+ TCLPD) and primary cutaneous marginal zone lymphoma/LPD (PCMZL/LPD). The latter is still classified as primary cutaneous marginal zone lymphoma (PCMZL) in the 5th edition of the World Health Organization classification. A survey was previously carried out among 30 cutaneous lymphoma centres on the effects of this new terminology on clinical management. The results revealed considerable heterogeneity and emphasized the need to develop uniform recommendations for management and treatment of these disorders. Our objective was to develop consensus recommendations for staging, treatment and follow-up in PCSM-TCLPD, acral CD8+ TCLPD and PCMZL/LPD. Two surveys with questions regarding staging, treatment and follow-up of cutaneous LPDs were distributed among 30 cutaneous lymphoma expert centres collaborating within the EORTC-CLTG, USCLC and ISCL. Consensus recommendations were formulated based on these surveys, an extensive literature search, two rounds of feedback and a final consensus meeting. Important changes compared with current practice and literature are as follows. (i) Staging examinations, other than thorough clinical examination of skin and peripheral lymph nodes, are not required in typical cases of PCSM-TCLPD and acral CD8+ TCLPD. (ii) Low-dose radiotherapy (4-8 Gy) can be used rather than dose ≥ 20 Gy for PCSM-TCLPD and acral CD8+ TCLPD, and 4 Gy can be used for PCMZL/LPD. The dose can be escalated to 20-24 Gy in the case of local failure. (iii) Intralesional corticosteroids are also recommended as initial treatment in all three LPDs. (iv) A limited follow-up period (2 years) is acceptable in PCSM-TCLPD and acral CD8+ TCLPD LPD. These EORTC/USCLC/ISCL consensus recommendations reflect the state-of-the-art management and treatment as agreed upon by major cutaneous lymphoma centres. They may contribute to uniform staging, treatment and follow-up policy in patients with cutaneous LPDs.

In the context of immunosuppression, most lymphoproliferative disorders are of B-cell origin and associated with Epstein-Barr virus (EBV). Follicular Helper T-cell Lymphoma, Angioimmunoblastic type (AITL) is the most frequently encountered T-cell lymphoma subtype. We present a challenging AITL case, initially misinterpreted as a polymorphic EBV + B-cell lymphoma, in a 62-year-old woman with a history of rheumatoid arthritis treated with multiple immunosuppressive agents. Over several years, she developed varied cutaneous manifestations with distinct histopathological infiltration patterns, prompting a diagnostic reassessment. Molecular studies demonstrated T-cell clonality, and RHOA and TET2 mutations, supporting the diagnosis of AITL with associated EBV + B-cell expansion. Notably, the presence of epidermotropic EBV + B-cell infiltrates masked the underlying T-cell neoplasm. This case underscores the importance of integrating histopathological, clinical, and molecular data, and highlights the diagnostic and biological complexity of AITL, particularly when it arises in the setting of immune dysregulation and exhibits features overlapping with EBV-driven B-cell proliferations.

This study shows that the microenvironment and probably the phenotype of neoplastic T cells of early-stage mycosis fungoides (MF) samples from patients with MF who suffered progression or remained stable are different. Moreover, we propose that the overexpression of CD30, CXCL13 and BIRC3 in early-stage MF is related to progression. Further spatial transcriptomic studies or single-cell analysis in further case series are needed to corroborate our findings.

Systemic mastocytosis with an associated myeloid neoplasm (SM-AMN) represents a diagnostic challenge. The first section of the XVI European Bone Marrow Working Group Workshop, held in Barcelona, Spain, in 2023, focused on such cases. Three main lessons were learned from the workshop. First, both the SM and the AMN components can mask each other. Second, because of their overlapping clinical and laboratory findings, it is usually impossible to recognize advanced systemic mastocytosis within an SM-AMN. In other words, unless the International Consensus Classification "C" findings were clearly caused by the SM, for purposes of classification, the SM component was regarded as not advanced. The distinction between indolent and smoldering SM was impossible, but the presence of mast cell leukemia as the SM component is usually recognizable and should be reported. Finally, the presence of myeloid gene mutations (other than KIT) were strongly associated with SM-AMN. These variations include SRFS2-p95, biallelic (double) TET2 or a TET2 mutation combined with an SRSF2 variation to identify chronic myelomonocytic leukemia associated with SM. Additional diagnostic issues included disease progression in the SM or the AMN component, the distinction between SM-AMN and acute myeloid leukemia with partial mast cell differentiation (aka, myelomastocytic leukemia), and rare types of disease proliferations occurring in SM-AMN.

Follicular lymphoma (FL) is a neoplasm that originates from germinal center B cells and typically forms at least a partial follicular pattern. Approximately 85% of FL cases harbor the t(14;18)(q32;q21)/IGH::BCL2 which leads to the overexpression of BCL2. These cases are referred to as classic FL in the current World Health Organization classification [1]. These neoplasms often exhibit hallmark epigenetic deregulation due to recurrent mutations in genes such as KMT2D, CREBBP, and EZH2, with KMT2D and CREBBP considered founding events in FL lymphomagenesis. In contrast, about 15% of FL cases are negative for the t(14;18), which could present diagnostic challenges. These cases may lack the typical genetic markers and require careful pathological and molecular analysis for accurate diagnosis. This review aims to provide an up-to-date pathology resource on FL, focusing on the pathological and molecular characteristics of these neoplasms. We will detail the diagnostic criteria for FL and emphasize the importance of genetic and mutational analyses in accurately characterizing and distinguishing FL subtypes. Furthermore, we will propose methodologies and best practices for the diagnostic work-up of FL to enhance diagnostic accuracy.

ABSTRACT:Plasmablastic lymphoma (PBL) is an uncommon and aggressive B-cell lymphoma with a poor prognosis. Some studies have described genetic alterations in PBL, but its transcriptome has been scarcely studied, and molecular mechanisms driving lymphomagenesis remain poorly understood. Our goal was to delineate transcriptomic profiles to identify potential biomarkers for novel targeted therapy in PBL. RNA sequencing uncovered an enrichment of cell cycle-related genes, including MYC and E2F targets, and genes involved in G2/M checkpoint in PBL. Microarray analyses discovered 2 microRNA expression signatures depending on the presence of MYC translocation. Interestingly, miR-150-5p was downregulated, whereas E2F3 and BIRC5 (survivin), a cell cycle activator and an antiapoptotic regulator, respectively, were upregulated. Increasing miR-150-5p in PBL-1 cells induced G1 cell cycle arrest, suppressed proliferation by transcriptionally repressing E2F3, and promoted apoptosis by the downregulation of BIRC5. Interestingly, the miR-150-5p tumor suppressor activity was diminished in E2F3-knockdown cells. The combined inhibition of E2F3 and survivin attenuated lymphomagenesis in PBL cells and suppressed tumor growth in a chorioallantoic membrane-derived xenograft model of PBL. Overall, our study highlights the pivotal role of the miR-150-5p/E2F3/survivin axis in boosting PBL lymphomagenesis and unveils new therapeutic targets for this lymphoma.

Neoadjuvant endocrine therapy (NET) for hormone receptor-positive (HR+) breast cancer might be as effective as chemotherapy, with a better toxicity profile. Blocking a crucial process such as angiogenesis with sunitinib may have a synergistic effect with NET. We aimed to assess the efficacy and safety of neoadjuvant sunitinib plus exemestane in early-stage HR+/HER2-negative breast cancer. In this phase I/II study, postmenopausal women with HR+/HER2- stage II-III breast cancer received neoadjuvant exemestane at conventional dose of 25mg plus sunitinib in a 3 + 3 design at 25mg (3/1weeks scheme) or 37.5mg continuous dose, for 6 months. Coprimary endpoints were the recommended dose of sunitinib combined with exemestane and objective response. Secondary endpoints included safety and biomarkers of early response. For 15 months, 18 patients were enrolled, 15 at sunitinib 25mg and 3 at 37.5mg. Median age was 73, 77% of patients had T2 tumors and 67% node-positive disease. The most common grade 2 toxicity was asthenia (44%), as was hypertension (22%) for grade 3. No grade 4-5 were reported. Twelve patients (66%) achieved an objective response. VEGFR-2 levels significantly decreased after one month of treatment. Differential gene expression analysis showed downregulation of ESR1, PGR and NAT1 in post-treatment samples and upregulation of EGFR, MYC, SFRP1, and FOXC1. PAM50 analysis on 83% of patients showed a prevalence of luminal A subtype, both in pre-treatment (63.6%) and post-treatment tumors (54.5%). Sunitinib plus exemestane was associated with substantial yet reversible toxicities, providing safety, efficacy and biological impact insights of combining an antiangiogenic drug with hormone therapy in early-stage breast cancer.Trial registration: Registered with ClinicalTrials.gov, NCT00931450. 02/07/2009

The Hodgkin and Reed - Sternberg (HRS) cells in classical Hodgkin Lymphoma (cHL) actively modify the immune tumor microenvironment (TME) attracting immunosuppressive cells and expressing inhibitory molecules. A high frequency of myeloid cells in the TME is correlated with an unfavorable prognosis, but more specific and rare cell populations lack precise markers. Myeloid-derived suppressor cells (MDSCs) have been identified in the peripheral blood of cHL patients, where they appear to be correlated with disease aggressiveness. TNFRSF9 (CD137) is a T cell co-stimulator expressed by monocytic and dendritic cells. Its expression has also been described in HRS cells, where it is thought to play a role in reducing antitumor responses. Here, we perform qualitative and quantitative analyses of lymphocytic and MDSC subtypes and determine the CD137 cell distribution in cHL primary tumors using multiplex immunofluorescence and automated multispectral imaging. The results were correlated with patients' clinical features. Cells were stained with specific panels of immune checkpoint markers (PD-1, PD-L1, CD137), tumor-infiltrating T lymphocytes (CD3, PD-1), and monocytic cells/MDSCs (CD68, CD14, CD33, Arg-1, CD11b). This approach allowed us to identify distinct phenotypes and to analyze spatial interactions between immune subpopulations and tumor cells. The results confirm CD137 expression by T, monocytic and HRS cells. In addition, the expression of CD137, T exhausted cells, and monocytic MDSCs (m-MDSCs) in the vicinity of malignant HRS cells were associated with a worse prognosis. Our findings reveal new elements of the TME that mediate immune escape, and confirm CD137 as a candidate target for immunotherapy in cHL.

The t(14;19)(q32;q13) often juxtaposes BCL3 with immunoglobulin heavy chain (IGH) resulting in overexpression of the gene. In contrast to other oncogenic translocations, BCL3 rearrangement (BCL3-R) has been associated with a broad spectrum of lymphoid neoplasms. Here we report an integrative whole-genome sequence, transcriptomic, and DNA methylation analysis of 13 lymphoid neoplasms with BCL3-R. The resolution of the breakpoints at single base-pair revealed that they occur in two clusters at 5' (n=9) and 3' (n=4) regions of BCL3 associated with two different biological and clinical entities. Both breakpoints were mediated by aberrant class switch recombination of the IGH locus. However, the 5' breakpoints (upstream) juxtaposed BCL3 next to an IGH enhancer leading to overexpression of the gene whereas the 3' breakpoints (downstream) positioned BCL3 outside the influence of the IGH and were not associated with its expression. Upstream BCL3-R tumors had unmutated IGHV, trisomy 12, and mutated genes frequently seen in chronic lymphocytic leukemia (CLL) but had an atypical CLL morphology, immunophenotype, DNA methylome, and expression profile that differ from conventional CLL. In contrast, downstream BCL3-R neoplasms were atypical splenic or nodal marginal zone lymphomas (MZL) with mutated IGHV, complex karyotypes and mutated genes typical of MZL. Two of the latter four tumors transformed to a large B-cell lymphoma. We designed a novel fluorescence in situ hybridization assay that recognizes the two different breakpoints and validated these findings in 17 independent tumors. Overall, upstream or downstream breakpoints of BCL3-R are mainly associated with two subtypes of lymphoid neoplasms with different (epi)genomic, expression, and clinicopathological features resembling atypical CLL and MZL, respectively.

Testicular large B-cell lymphoma (TLBCL) is an infrequent and aggressive lymphoma arising in an immune-privileged site and has recently been recognized as a distinct entity from diffuse large B-cell lymphoma (DLBCL). We describe the genetic features of TLBCL and compare them with published series of nodal DLBCL and primary large B-cell lymphomas of the CNS (PCNSL). We collected 61 patients with TLBCL. We performed targeted next-generation sequencing, copy number arrays, and fluorescent in situ hybridization to assess chromosomal rearrangements in 40 cases with available material. Seventy percent of the cases showed localized stages. BCL6 rearrangements were detected in 36% of cases, and no concomitant BCL2 and MYC rearrangements were found. TLBCL had fewer copy number alterations (p < 0.04) but more somatic variants (p < 0.02) than nodal DLBCL and had more frequent 18q21.32-q23 (BCL2) gains and 6q and 9p21.3 (CDKN2A/B) deletions. PIM1, MYD88 L265P , CD79B, TBL1XR1, MEF2B, CIITA, EP300, and ETV6 mutations were more frequent in TLBCL, and BCL10 mutations in nodal DLBCL. There were no major genetic differences between TLBCL and PCNSL. Localized or disseminated TLBCL displayed similar genomic profiles. Using LymphGen, the majority of cases were classified as MCD. However, we observed a subgroup of patients classified as BN2, both in localized and disseminated TLBCL, suggesting a degree of genetic heterogeneity in the TLBCL genetic profile. TLBCL has a distinctive genetic profile similar to PCNSL, supporting its recognition as a separate entity from DLBCL and might provide information to devise targeted therapeutic approaches.

Peripheral T-cell lymphomas with gamma-delta phenotype (GDTCL) are rare lymphoid malignancies. Beyond the well-recognized entities of extranodal lymphomas with gamma-delta phenotype as defined by the fifth edition of the World Health Organization Classification of Hematolymphoid Tumors and 2022 International Consensus Classification, there is a group of poorly defined gamma-delta T-cell lymphomas with predominantly nodal presentation, termed as nodal GDTCL (nGDTCL). In this study, we present a series of 12 cases of Epstein-Barr virus-negative nGDTCL, highlighting the clinical, histopathological, and molecular features of this rare entity. Seven cases reported in the literature were included in the analysis. Of the 12 cases, nGDTCL shows an increased incidence in elderly men, with a median age of 65.5 years. All cases presented primarily with enlarged lymph nodes, and 4 cases (4/12, 33.3%) showed involvement of extranodal sites, including skin, liver, spleen, and bone marrow. Histologically, 9 cases showed a diffuse and monomorphic proliferation of mostly medium-to-large lymphoid cells, whereas 3 cases demonstrated lymphoepithelioid morphology. All cases (12/12, 100%) were positive for CD3 and TCRγδ. CD4, CD8, and CD56 were positive in 66.7% (8/12), 25% (3/12), and 8.3% (1/11) of cases, respectively. Most cases (8/12, 66.7%) showed a noncytotoxic phenotype. Using immunohistochemistry, the majority of cases (6/8, 75.0%) belonged to the peripheral T-cell lymphoma-GATA3 subtype with GATA3 and/or CCR4 expression and a noncytotoxic CD4-positive phenotype. Two cases (2/8, 25%) belonged to the peripheral T-cell lymphoma-TBX21 subtype, of which 1 displayed a cytotoxic CD8-positive phenotype. Next-generation sequencing was performed in 9 cases, and TP53 mutation was detected in 66.7% (6/9) of the cases. Mutations of ATM and KSR2 were identified in 2 cases each. It remains uncertain whether nGDTCL represents a distinct entity, and further studies are needed for better characterization. Nonetheless, nodal-based GDTCL should be distinguished from secondary nodal involvement by other extranodal GDTCL and Epstein-Barr virus-positive T/NK-cell lymphoproliferative diseases.

Mantle cell lymphoma (MCL) is genetically characterized by the IG::CCND1 translocation mediated by an aberrant V(D)J rearrangement. CCND1 translocations and overexpression have been identified in occasional aggressive B-cell lymphomas with unusual features for MCL. The mechanism generating CCND1 rearrangements in these tumors and their genomic profile are not known. We have reconstructed the IG::CCND1 translocations and the genomic profile of 13 SOX11-negative aggressive B-cell lymphomas using whole genome/exome and target sequencing. The mechanism behind the translocation was an aberrant V(D)J rearrangement in three tumors and by an anomalous IGH class-switch recombination (CSR) or somatic hypermutation (SHM) mechanism in ten. The tumors with a V(D)J-mediated translocation were two blastoid MCL and one high-grade B-cell lymphoma. None of them had a mutational profile suggestive of DLBCL. The ten tumors with CSR/SHM-mediated IGH::CCND1 were mainly large B-cell lymphomas, with mutated genes commonly seen in DLBCL and BCL6 rearrangements in 6. Two cases, which transformed from marginal zone lymphomas, carried mutations in KLF2, TNFAIP3 and KMT2D. These findings expand the spectrum of tumors carrying CCND1 rearrangement that may occur as a secondary event in DLBCL mediated by aberrant CSR/SHM and associated with a mutational profile different from that of MCL.

Follicular lymphoma (FL) is the most frequent indolent lymphoma. Some patients (10%-15%) experience histologic transformation (HT) to a more aggressive lymphoma, usually diffuse large B-cell lymphoma (DLBCL). This study aimed to validate and improve a genetic risk model to predict HT at diagnosis.We collected mutational data from diagnosis biopsies of 64 FL patients. We combined them with the data from a previously published cohort (total n = 104; 62 from nontransformed and 42 from patients who did transform to DLBCL). This combined cohort was used to develop a nomogram to estimate the risk of HT. Prognostic mutated genes and clinical variables were assessed using Cox regression analysis to generate a risk model. The model was internally validated by bootstrapping and externally validated in an independent cohort. Its performance was evaluated using a concordance index and a calibration curve. The clinicogenetic nomogram included the mutational status of 3 genes (HIST1HE1, KMT2D, and TNFSR14) and high-risk Follicular Lymphoma International Prognostic Index and predicted HT with a concordance index of 0.746. Patients were classified as being at low or high risk of transformation. The probability HT function at 24 months was 0.90 in the low-risk group vs 0.51 in the high-risk group and, at 60 months, 0.71 vs 0.15, respectively. In the external validation cohort, the probability HT function in the low-risk group was 0.86 vs 0.54 in the high-risk group at 24 months, and 0.71 vs 0.32 at 60 months. The concordance index in the external cohort was 0.552. In conclusion, we propose a clinicogenetic risk model to predict FL HT to DLBLC, combining genetic alterations in HIST1H1E, KMT2D, and TNFRSF14 genes and clinical features (Follicular Lymphoma International Prognostic Index) at diagnosis. This model could improve the management of FL patients and allow treatment strategies that would prevent or delay transformation.

Adult T-cell leukemia-lymphoma (ATLL) is an aggressive malignancy driven by human T-cell leukemia virus type 1 (HTLV-1). Although patients from the Western hemisphere (Afro-Caribbean and South American) face worse prognoses, our understanding of ATLL molecular drivers derives mostly from Japanese studies. We performed multi-omic analyses to elucidate the genomic landscape of ATLL in Western cohorts. Recurrent deletions and/or damaging mutations involving FOXO3, ANKRD11, DGKZ, and PTPN6 implicate these genes as potential tumor suppressors. RNA-sequencing, published functional data and in vitro assays support the roles of ANKRD11 and FOXO3 as regulators of T-cell proliferation and apoptosis in ATLL, respectively. Survival data suggest that ANKRD11 mutation may confer a worse prognosis. Japanese and Western cohorts, in addition to acute and lymphomatous subtypes, demonstrated distinct molecular patterns. GATA3 deletion was associated with chronic cases with unfavorable outcomes. IRF4 and CARD11 mutations frequently emerged in relapses after interferon therapy. Our findings reveal novel putative ATLL driver genes and clinically relevant differences between Japanese and Western ATLL patients.

Aggressive large B-cell lymphomas (aLBCL) include a heterogeneous group of lymphomas with diverse biological features. One of the approaches to the diagnosis of aLBCL is based on the identification of MYC rearrangements ( MYC -R), in addition to BCL2 and BCL6 rearrangements by genetic techniques, mainly fluorescent in situ hybridization (FISH). Because of the low incidence of MYC -R, the identification of useful immunohistochemistry markers to select cases for MYC FISH testing may be useful in daily practice. In a previous work, we identified a strong association between the profile CD10 positive/LMO2 negative expression and the presence of MYC -R in aLBCL and obtained good intralaboratory reproducibility. In this study, we wanted to evaluate external reproducibility. To evaluate whether LMO2 can be a reproducible marker between observers 50 aLBCL cases were circulated among 7 hematopathologists of 5 hospitals. Fleiss’ kappa index for LMO2 and MYC were 0.87 and 0.70, respectively, indicating high agreement between observers. In addition, during 2021–2022, the enrolled centers included LMO2 in their diagnostic panels to evaluate prospectively the utility of the marker, and 213 cases were analyzed. Comparing LMO2 with MYC, the group of CD10 positive cases showed higher specificity (86% vs 79%), positive predictive value (66% vs 58%), likelihood positive value (5.47 vs 3.78), and accuracy (83% vs 79%), whereas the negative predictive values remained similar (90% vs 91%). These findings place LMO2 as a useful and reproducible marker to screen MYC -R in aLBCL.