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A 67-year-old man visited our hospital complaining of dark-colored urine and upper abdominal pain. Magnetic resonance cholangiopancreatography showed stricture of the distal bile duct, and contrast-enhanced computed tomography showed irregular thickening of the distal bile duct wall. However, no enlarged lymph nodes, pancreatic tumors, or other neoplastic lesions were apparent around the bile duct. Endoscopic ultrasonography and intraductal ultrasonography showed irregular thickening of the inner hypoechoic layer without the disappearance of the innermost thin hyperechoic layer. On the basis of these findings, we considered that the bile duct lesion was of non-epithelial origin. Thus, we repeatedly performed bile duct biopsies from the same site under fluoroscopy to obtain a sample of the submucosal tissue. The pathological diagnosis was diffuse large B-cell lymphoma, and the patient received systemic chemotherapy (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone). After six courses of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone, positron emission tomography-computed tomography showed the disappearance of 18-fluorodeoxyglucose uptake in the bile duct and endoscopic retrograde cholangiography showed improvement of the bile duct stricture. Endoscopic findings and repeated biopsies were useful in making the diagnosis of primary biliary diffuse large B-cell lymphoma.

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Diffuse large B cell lymphoma (DLBCL) is the most diagnosed, aggressive non-Hodgkin lymphoma, with ~40% of patients experiencing refractory or relapsed disease. Given the low response rates to current therapy, alternative treatment strategies are necessary to improve patient outcomes. Here, we sought to develop an easily accessible new xenograft mouse model that better recapitulates the human disease for preclinical studies. We generated two Luciferase (Luc)-EGFP-expressing human DLBCL cell lines representing the different DLBCL cell-of-origin subtypes. After intravenous injection of these cells into humanized NSG mice, we monitored the tumor growth and evaluated the organ-specific engraftment/progression period. Our results showed that human IL6-expressing NSG (NSG-IL6) mice were highly permissive for DLBCL cell growth. In NSG-IL6 mice, systemic engraftments of both U2932 activated B cell-like- and VAL germinal B cell-like-DLBCL (engraftment rate; 75% and 82%, respectively) were detected within 2nd-week post-injection. In the organ-specific ex vivo evaluation, both U2932-Luc and VAL-Luc cells were initially engrafted and expanded in the spleen, liver, and lung and subsequently in the skeleton, ovary, and brain. Consistent with the dual BCL2/MYC translocation association with poor patient outcomes, VAL cells showed heightened proliferation in human IL6-conditioned media and caused rapid tumor expansion and early death in the engrafted mice. We concluded that the U2932 and VAL cell-derived human IL6-expressing mouse models reproduced the clinical features of an aggressive DLBCL with a highly consistent pattern of tumor development. Based on these findings, NSG mice expressing human IL6 have the potential to serve as a new tool to develop DLBCL xenograft models to overcome the limitations of standard subcutaneous DLBCL xenografts.

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Bispecific antibodies (bsAbs) are an emerging therapy in the treatment of large B-cell lymphomas (LBCLs). There is a gap in the research on the safety and efficacy of bsAbs in adults with LBCL, with current research focusing on the wider non-Hodgkin's lymphoma population. To address this research gap, we conducted a systematic review aiming to evaluate the safety and efficacy outcomes of bsAbs in adults with LBCL. A systematized search was conducted in PubMed, EMBASE, and CENTRAL on 10 April 2024. Interventional clinical trials were eligible for inclusion. Observational studies, reviews, and meta-analyses were excluded. According to the Revised Risk of Bias Assessment Tool for Nonrandomized Studies, the included studies were largely of a high quality for safety outcome reporting, but of mixed quality for efficacy outcome reporting. Due to the heterogeneity of the included studies, the results were discussed as a narrative synthesis. Nineteen early phase studies were evaluated in the final analysis, with a pooled sample size of 1332 patients. Nine bsAbs were investigated across the studies as monotherapy (nine studies) or in combination regimes (10 studies). The rates of cytokine release syndrome were variable, with any grade events ranging from 0 to 72.2%. Infection rates were consistently high across the reporting studies (38-60%). Cytopenias were found to be common, in particular, anemia (4.4-62%), thrombocytopenia (3.3-69%), and neutropenia (4.4-70%). Immune effector cell-associated neurotoxicity syndrome (ICANS) and grade ≥3 adverse events were not commonly reported. Promising efficacy outcomes were reported, with median overall response rates of 95-100% in the front-line and 36-91% in terms of relapsed/refractory disease. The results of this systematic review demonstrate that bsAbs are generally well-tolerated and effective in adults with LBCL. BsAbs appear to have superior tolerability, but inferior efficacy to CAR T-cell therapies in adults with LBCL. Future research on safety and efficacy should focus on evaluating adverse event timing and management, the impact on the patient's quality of life, the burden on the healthcare system, and overall survival outcomes.

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We report a case of diffuse large B-cell lymphoma (DLBCL) of the gallbladder with extensive hepatoduodenal invasion, which was challenging to diagnose histologically due to a strong tendency to be necrotic. An 71 year-old man presented with upper abdominal pain and was referred to our hospital. Computed tomography revealed a distended gallbladder with air within the irregular gallbladder wall and an indistinct border with the hepatoduodenum, suggesting invasion. Esophagogastroduodenoscopy detected an ulceration in the duodenal bulb. However, histologic analysis failed to provide a definitive diagnosis due to the presence of necrotic tissue. Furthermore, direct biopsy from the gallbladder mucosa by endoscopic retrograde cholangiography revealed only necrotic tissue and no diagnosis. Contrast ultrasonography for the hepatic invasion revealed enhancement with blood flow, suggesting non-necrotic tissue. Subsequently, an ultrasound-guided core-needle biopsy was conducted to obtain tissue samples from the described lesion. The pathology showed atypical lymphocytes with irregular nuclei. Immunostaining indicated positive expression of CD10, CD20, Bcl-6, and C-Myc, consistent with a diagnosis of DLBCL. In our case, the lymphoma exhibited a strong tendency to be necrotic, making histologic diagnosis difficult. However, selective biopsy from the site of blood flow made the diagnosis possible and proved to be useful.

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BACKGROUND: Double-hit lymphoma (DHL) with c-MYC gene translocation is highly aggressive and has a poor prognosis. In DHL cells, activation-induced cytidine deaminase (AID) promotes antibody class switch recombination (CSR), ultimately leading to c-MYC gene translocation caused by Myc/IgH DNA double-strand breaks. However, currently there is still no method to suppress the expression of AID. METHODS: In this study, we compared the clinical significance of AID expression in DHL, Additionally, two human double-hit lymphoma cell lines were used to analyze the effect of imatinib mesylate on c-MYC in vitro, and the therapeutic effect was also evaluated in xenograft mouse models. RESULTS: Imatinib mesylate downregulated the AID and c-MYC proteins in patients with chronic myelogenous leukemia associated with DHL. In addition, imatinib mesylate reduced AID and c-MYC expression in SU-DHL-4 and OCI-Ly18 DHL cells. Imatinib mesylate exerted significant inhibitory effects on the proliferation and metastasis of SU-DHL-4 and OCI-Ly18 cells. Finally, imatinib mesylate reduced not only tumor burden in DHL mouse models, but also AID and c-MYC expression in vivo. CONCLUSION: These findings reveal that imatinib mesylate effectively reduces the carcinogenic function of c-MYC in DHL, providing novel strategies for developing therapies targeting c-MYC-driven DHL.

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BACKGROUND: This study evaluates the health-related quality of life (HRQoL) of persons with diffuse large B-cell lymphoma (DLBCL) by using EQ-5D-5L and SF-6Dv2 and compares the measurement properties of the two instruments. METHOD: DLBCL patients were identified via a patient group and were surveyed using web-based questionnaires. Demographic information, socioeconomic status (SES), clinical characteristics, and EQ-5D-5L and SF-6Dv2 responses were collected and statistically described. The association between the EQ-5D-5L and SF-6Dv2 dimensions were analyzed using the Spearman's correlation coefficient, whereas the correlation of the utility scores was evaluated using Pearson's correlation coefficient. The agreement between the responses of the two instruments were examined using a Bland-Altman (B-A) plot. A one-way analysis of variance (ANOVA) was performed to compare the utility scores across subgroups in different clinical states (a t-test was used if there were two subgroups). In addition, the graded response model (GRM) was used to describe the discrimination ability and difficulty characteristics of the dimensions in the two instruments. RESULTS: In total, 582 valid responses were collected, among which 477 respondents were associated with initial-treatment and 105 respondents were relapsed/refractory (RR) patients. The mean (standard deviation [SD]) EQ-5D-5L and SF-6Dv2 utility scores of the DLBCL patients were 0.828 (0.222) and 0.641 (0.220), respectively. The correlation between the EQ-5D-5L and SF-6Dv2 dimensions ranged from 0.299 to 0.680, and the correlation between their utility scores was 0.787. The B-A plot demonstrated an acceptable but not strong agreement between EQ-5D-5L and SF-6Dv2 utility scores. The GRM model results indicated that all dimensions of each instrument were highly discriminating overall, but EQ-5D-5L had suboptimal discriminative power among patients with good health. CONCLUSION: Both the EQ-5D-5L and SF-6Dv2 showed valid properties to assess the HRQoL of DLBCL patients. However, utility scores derived from the two instruments had substantial difference, thereby prohibiting the interchangeable use of utilities from the two instruments.

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BACKGROUND: In this study, we compare outcomes of older patients with primary diffuse large B-cell lymphoma of the central nervous system (PCNSL) undergoing autologous hematopoietic cell transplantation (autoHCT) with either thiotepa/carmustine (BCNU/Thio) or thiotepa/busulfan/cyclophosphamide (TBC) conditioning. METHODS: We used a post-publication dataset made available by the Center for International Blood and Marrow Research (CIBMTR) including patients who were ≥65 years in age with PCNSL and underwent autoHCT as consolidation with TBC or BCNU/Thio conditioning. RESULTS: Out of 147 patients; n=84 received BCNU/Thio and n=63 received TBC. The 1-year NRM in the BCNU/Thio group was 10% versus 22% in the TBC group (p=0.05) and the 2-year relapse rate was 5% versus 5%, respectively (p=1.00). The 2-year PFS in the BCNU/Thio group was 85% versus 71% in the TBC group (p=0.05) and 2-year OS was 86% vs 74% (p=0.08). In a multivariable regression model, BCNU/Thio was associated with a lower risk for NRM [Hazard Ratio (HR), 0.33, p=0.009], improved PFS (HR, 0.41, p=0.008) and OS (HR, 0.37, p=0.007), but there was no association with relapse risk. CONCLUSION: We found that in older adults with PCNSL undergoing consolidation with autoHCT, BCNU/Thio conditioning is associated with lower NRM and improved OS compared to TBC.

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Diffuse large B-cell lymphoma (DLBCL) is a common malignancy among people living with HIV. Macrophage enrichment of the tumour microenvironment (TME) is a prognostic factor in DLBCL among immunocompetent people, with some studies reporting that macrophage enrichment predicts a superior response to rituximab therapy. The macrophage phenotype is also important, with reportedly poorer outcomes with enrichment of anti-inflammatory (M2) macrophages. To date, the relationship between the type/number of tumour macrophages and outcomes in HIV-associated DLBCL (HIV-DLBCL) has been poorly explored. In this study, we assessed tumour macrophage numbers in a South African cohort of patients with DLBCL and a high HIV-seropositivity rate. Immunohistochemistry for CD68 and CD163 was performed on the diagnostic biopsies of 79 patients with DLBCL. Relevant information was documented from the clinical records, including disease stage, international-prognostic index score, HIV-related parameters, C-reactive protein, ferritin levels and immune cell numbers (monocytes, lymphocytes and neutrophils). Survival analysis was performed using Kaplan-Meier survival estimates, and the correlation between tumour macrophage numbers and a variety of immunological parameters was assessed using Spearman's rho. Of the 79 patients included, 87.2% were living with HIV, and rituximab therapy was used in 46.9%. Tumour macrophage numbers were not related to HIV status, but low pro-inflammatory (M1) macrophage numbers (CD68 + CD163 -) were significantly associated with poorer outcomes (HR 2.02, p = 0.03). M2 macrophage (CD68 + CD163 +) enrichment was not predictive of survival but was associated with improved response to rituximab therapy (HR 0.19; p = 0.002). Macrophage numbers were marginally correlated with ferritin levels, which showed modest performance as a peripheral blood biomarker of the TME macrophage status (AUC 0.6 at a level of 374 µg/L), and high ferritin levels were associated with a superior response to rituximab-therapy (HR 0.28, p = 0.034). Pro-inflammatory macrophages are important in tumour control in HIV-DLBCL, while M2 macrophage enrichment improves the response to rituximab therapy. Ferritin shows promise as a biomarker for identifying patients more likely to benefit from rituximab therapy.

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We describe a patient with extra-limbic seronegative encephalitis with relapsing progressive course as the harbinger of sequential Hodgkin's lymphoma and Diffuse Large B-Cell lymphoma. Diagnosis of probable paraneoplastic neurologic syndrome (PNS) was arrived at by exhaustive elimination of alternative causes and supportive tissue diagnosis. This case highlights the phenotypic variety of paraneoplastic neurologic syndromes associated with hematologic malignancies and the challenges in their recognition, diagnosis, and treatment. We discuss and apply the updated consensus diagnostic criteria for paraneoplastic syndromes to our case as a means of bolstering probability in cases of diagnostic uncertainty.

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Guillain-Barré syndrome (GBS) is an acute disorder of the peripheral nervous system, causing flaccid paralysis, areflexia, and variable sensory involvement. Proximal as well distal muscles of the limbs can be involved, and in most severe and advanced cases progresses to respiratory failure and death. GBS is considered an autoimmune disease, and at the basis of the attack at the peripheral nervous system different mechanisms have been recognized, in particular viral infections or other immune stimulations. Cranial nerve involvement in patients with diffuse large B-cell lymphoma (DLBCL) and primary central nervous system lymphoma are rare conditions that could present with similar clinical features. Here we present a case of a 36-year-old man hospitalized for acute polyradiculoneuritis of the cranial nerves and lumbar roots that arose a 14 days after severe acute respiratory syndrome COVID-19 2 (Sars-CoV-2) vaccination. Most of the main criteria for the diagnosis of GBS were met, including clinical and electrophysiological criteria. Albuminocytologic dissociation and high protein level in cerebrospinal fluid were also found. Therefore, the patient was treated with a cycle of intravenous immunoglobulin (IVIG) with notable improvement of symptoms and gradual recovery of motility. A five months later, following SARS-CoV-2 infection, the patient presented with worsening of neurological symptoms and was readmitted to the hospital. He underwent instrumental tests again and was treated with repeated cycles of IVIG and then with a cycle of plasmapheresis without any improvement. In the following 10 days he developed very serious conditions; he was transferred to intensive care unit and deceased after 6 days. The cause of the neurological syndrome was determined only after autoptic analysis, which revealed the presence of primary peripheral nervous system (PNS) DLBCL. The reported case highlights that GBS-like presentation always requires a careful differential diagnosis, and physicians should also consider the possibility of an occult cancer.

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Since over one-third of DLBCL patients experience relapse or refractory after standard therapy, high-risk patients must be predicted. We developed a prognostic immune-related gene pairs (IRGPs) signature for DLBCL patients using bioinformatics analyses. This signature can predict the prognosis of these patients adequately, either alone or in combination with other clinical parameters. It hopes to improve the stratification and management of these patients for broad clinical applications.

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Diffuse large B cell lymphoma (DLBCL) is a heterogeneous and aggressive B cell malignancy that accounts for about 30 % of non-Hodgkin lymphomas. The current standard treatment for DLBCL is rituximab plus chemotherapy, but many patients are refractory or relapse, indicating the need for improved understanding of its molecular pathology. T cell exhaustion is a state of dysfunction or impairment that occurs in chronic infections or cancers, and is associated with poor prognosis in DLBCL. However, the molecular mechanisms of T cell exhaustion in DLBCL are poorly understood. In this study, we performed a comprehensive analysis of T cell exhaustion in DLBCL using public single-cell transcriptome data. We identified different subtypes of T cells and characterized their gene expression features. We found that DLBCL had a significantly higher proportion of exhausted T cells than normal tonsil, and that exhausted T cells had distinct gene expression signatures from non-exhausted T cells. These signatures included genes related to inhibitory receptors, cytokines, transcription factors and metabolic enzymes. We also found that ID3 gene was significantly upregulated in exhausted T cells in DLBCL, which may play a key role in T cell exhaustion. We constructed a protein-protein interaction network, identifying major hub proteins involved in T cell exhaustion or migration. We also performed KEGG and GO enrichment analysis for the differentially expressed genes between exhausted and non-exhausted T cells, and found important signaling pathways related to T cell exhaustion in DLBCL. Our results provide new insights into the molecular mechanisms underlying T cell exhaustion and offer novel therapeutic targets for this complex disease.

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Lymphoma arises from mature B, T, and natural killer (NK) cells. Lymphomas are classified into Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL). Diffuse large B-cell lymphoma (DLBCL) is a type of NHL. It can present with symptoms such as fever, chills, or night sweats, as well as symptoms due to extranodal involvement. Extranodal sites can include the gastrointestinal tract or renal involvement. A higher risk of developing diffuse large B-cell lymphoma (DLBCL) is seen in patients with congenital or acquired immunodeficiency, those on immunosuppression, and those with autoimmune disorders. In this case report, we present a case of pericardial effusion that, upon further evaluation, was diagnosed as diffuse large B-cell lymphoma (DLBCL). A 64-year-old male presented with complaints of retrosternal chest pain that progressed from New York Heart Association (NYHA) Grade II to IV over a month. The chest pain was moderate intensity, dull aching, and non-radiating. It was associated with orthopnea, paroxysmal nocturnal dyspnea, and anasarca. A chest X-ray (posteroanterior {PA} view) showed cardiomegaly with an increased cardiothoracic ratio, mediastinal widening, and pulmonary congestion. Echocardiography revealed moderate non-tappable pericardial effusion. A high-resolution computed tomography (HRCT) chest scan showed moderate pericardial effusion and a homogeneous enhancing mass in the left anterior superior mediastinum. A computed tomography (CT)-guided biopsy was performed to check for lymphoma, thymoma, or tuberculosis. The patient was diagnosed with diffuse large B-cell lymphoma (DLBCL). Owing to the diverse manifestations of diffuse large B-cell lymphoma (DLBCL), prompt diagnosis is required for controlling disease progression.

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Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma and is associated with a poor prognosis. Data from the Gene Expression Profiling Interactive Analysis (GEPIA) database revealed dysregulated expression of several ubiquitin-specific proteases (USPs) in DLBCL tissues (DLBCL vs. non-DLBCL = 47 vs. 337), including USP19 (log2fold change = 1.17, P < 0.05). USP19 is closely linked to tumorigenesis, but its role in DLBCL progression remains largely unknown. Here, we investigated the role of USP19 in DLBCL development. Genetic manipulation of USP19 using adenovirus-based vectors was performed in two DLBCL cell lines, SUDHL4 and DB cells. The results showed that USP19 knockdown suppressed the proliferation, anchorage-independent growth and xenograft tumor formation of DLBCL cells and arrested the cell cycle at the G1 stage. In parallel, DLBCL cells overexpressing USP19 acquired a more malignant phenotype. Next, to explore USP19 interactors, we performed co-immunoprecipitation/liquid chromatography-mass spectrometry and identified potential interacting proteins. Among them, Parkinson disease protein 7 (PARK7), a member of the peptidase C56 family known to be involved in carcinogenesis, was further validated to bind with and be stabilized by USP19. Additionally, we found that USP19 induced PARK7 deubiquitylation in both DLBCL cell lines, and PARK7 acted as a downstream effector of USP19 in regulating the growth of DLBCL cells. Collectively, USP19 exerts a tumor-promoting role in DLBCL through interacting with and stabilizing PARK7.

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A captive 17-year-old male cynomolgus monkey (Macaca fascicularis) developed diffuse large B-cell lymphoma (DLBCL). This was the first report of DLBCL presenting with a mandible mass and violation of the paranasal sinus in a cynomolgus monkey. The neoplasm showed marked microscopical malignant aspects. Immunohistochemical staining showed strong positive expression of CD20. These features may contribute to the diagnosis and therapeutics of DLBCL in NHPs.

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Diffuse large B-cell lymphoma (DLBCL) is the most prevalent subtype of non-Hodgkin lymphoma (NHL) in domestic dogs, with many similarities to its human counterpart. The progression of the disease is rapid, and treatment must be initiated early to achieve cancer remission and extend life. This study examined the relationship between progression-free survival (PFS) and microRNA (miRNA) expression in dogs with DLBCL. miRNAs are small non-coding RNA molecules that typically regulate gene expression post-transcriptionally. They are involved in several pathophysiological processes, including the growth and progression of cancer. Based on the analysis of small RNA sequencing (sRNA-seq) data, we validated a group of miRNAs in lymph nodes from 44 DLBCL-affected dogs with known outcomes. We used quantitative PCR to quantify their expression and report a specific subset of miRNAs is associated with decreased PFS in dogs with DLBCL. The miR-192-5p and miR-16-5p expression were significantly downregulated in dogs with increased PFS. These results indicate that miRNA profiling may potentially identify dogs with DLBCL that will experience poor outcomes following treatment. Identifying specific miRNAs that correlate with the progression of canine DLBCL could aid the development of individualized treatment regimens for dogs.

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Diffuse large B-cell lymphoma (DLBCL) is the most common B-cell malignancy worldwide. Molecular classifications have tried to improve cure rates. We prospectively examined and correlated the mutational landscape with the clinical features and outcomes of 185 Mexican patients (median age 59.3 years, 50% women) with newly diagnosed DLBCL. A customized panel of 79 genes was designed, based on previous international series. Most patients had ECOG performance status (PS) < 2 (69.2%), advanced-stage disease (72.4%), germinal-center phenotype (68.1%), and double-hit lymphomas (14.1%). One hundred and ten (59.5%) patients had at least one gene with driver mutations. The most common mutated genes were as follows: TP53, EZH2, CREBBP, NOTCH1, and KMT2D. The median follow-up was 42 months, and the 5-year relapse-free survival (RFS) and overall survival (OS) rates were 70% and 72%, respectively. In the multivariate analysis, both age > 50 years and ECOG PS > 2 were significantly associated with a worse OS. Our investigation did not reveal any discernible correlation between the presence of a specific mutation and survival. In conclusion, using a customized panel, we characterized the mutational landscape of a large cohort of Mexican DLBCL patients. These results need to be confirmed in further studies.

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Background: High-risk double-expressor diffuse large B-cell lymphoma has an inferior prognosis following standard first-line therapy. After failure of second-line therapy, treatment options are limited if accompanied by localized compressive symptoms. Chimeric Antigen Receptor T cell (CAR-T) therapy preceded by bridging radiotherapy may be an effective emerging therapy. Case presentation: We report a 66-year-old female patient diagnosed with stage IV double-expressor diffuse large B-cell lymphoma. The patient achieved progressive disease after two cycles of rituximab, cyclophosphamide, liposomal doxorubicin, vincristine, and prednisone and continued to develop cervical lymph node recurrence after second-line therapy. The patient was infused with CAR-T cells after receiving focal bridging radiotherapy and remained in complete response more than 9 months after treatment. In addition, the patients did not experience serious adverse reactions related to radiotherapy as well as CAR-T cell therapy. Conclusions: In this article, we describe a patient with double-expressor diffuse large B-cell lymphoma with localized compression symptoms after second-line treatment failure who benefited from CAR-T combined with focal bridging radiotherapy.

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INTRODUCTION AND IMPORTANCE: Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin's lymphoma (NHL), known for its aggressive nature and tendency for extranodal extension. Extranodal involvement occurs in up to 40 % of cases, with primary lymphoma in soft tissue, particularly skeletal muscle, being exceedingly rare. This report presents a rare case of primary extranodal DLBCL in the calf muscle. CASE PRESENTATION: A 35-year-old man presented with an ulceroproliferative growth in left calf muscle, initially diagnosed as squamous cell carcinoma (SCC). Imaging studies, including CECT and MRI, were inconclusive, prompting a histological examination. Biopsy revealed large malignant cells with high mitotic activity, positive for LCA, CD20, BCL-2, MUM1, and CD10, confirming a diagnosis of primary extranodal DLBCL. The patient underwent resection followed by six cycles of chemotherapy (R-CHOP) and field radiation therapy. A follow-up PET showed significant improvement, with no evidence of disease recurrence. CLINICAL DISCUSSION: DLBCL often presents with rapidly growing tumors in lymph nodes or extranodal sites. Primary skeletal muscle lymphoma, particularly of the DLBCL subtype, is extremely rare, constituting about 0.5 % of extranodal lymphomas. Diagnosis typically involves imaging and biopsy, with immunohistochemistry (IHC) being crucial for accurate classification and treatment planning. CONCLUSION: DLBCL, while common among NHLs, rarely presents as primary extranodal lymphoma in skeletal muscle. The presented case underscores the importance of considering DLBCL in differential diagnoses for atypical soft tissue masses and the effectiveness of R-CHOP chemotherapy in managing this rare presentation. Prompt and appropriate treatment, such as R-CHOP chemotherapy, is essential for favorable outcomes.

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A 65-year-old man with generalized lymphadenopathy was diagnosed with classical Hodgkin lymphoma-Mixed cellularity via left cervical lymph node biopsy. Initial treatment with doxorubicin, bleomycin, vinblastine, and dacarbazine led to complete metabolic remission (CMR); however, recurrence developed after 6 months. Brentuximab vedotin induced partial remission followed by systemic relapse after 10 months. Nivolumab led to a second CMR, but disease progression persisted over nearly 4 years, despite treatment adjustments and local radiotherapy. Eventually, the patient was diagnosed with diffuse large B-cell lymphoma during routine esophagogastroduodenoscopy. Four courses of rituximab-CHOP therapy led to a CMR. This case highlights the importance of performing re-biopsies to detect the recurrence or progression of lymphoma.