Mediastinal Lymphoma Research Articles

A diagnostic model based on 18F-FDG PET/CT parameters in improving the differential diagnosis of invasive thymic epithelial tumors and anterior mediastinal lymphomas

BackgroundAccurately distinguishing between invasive thymic epithelial tumors (TETs) and anterior mediastinal lymphoma before surgery is crucial for subsequent treatment choices. But currently, the diagnosis of invasive TET is sometimes difficult to distinguish from anterior mediastinal lymphoma.ObjectiveTo assess the application of fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography/computer tomography (PET/CT) in the differential diagnosis of TETs and anterior mediastinal lymphomas.Methods18F-FDG PET/CT images of 133 invasive TETs and anterior mediastinal lymphomas patients were retrospectively analyzed. In particular, the tumor’s longest diameter and maximum standardized uptake value (SUVmax) were evaluated. The SUVmax and longest diameter values of the two groups were analyzed by using the receiver operating characteristic (ROC) curve to determine the optimal threshold and diagnostic efficiency.ResultsAge, myasthenia gravis, SUVmax and tumor longest diameter differed significantly between invasive TETs and anterior mediastinal lymphomas patients. The tumor location, calcification, relationship with adjacent vessels and distant metastasis differed significantly between the groups. The ROC analysis showed an AUC for SUVmax and tumor longest diameter of 0.841 and 0.737. Respectively, the cutoff values with the best diagnostic performance were 9.65 (sensitivity: 77.78%, specificity: 81.97%) and 6.65 (sensitivity: 80.56%, specificity: 62.30%) for SUVmax and tumor longest diameter. The diagnostic model of SUVmax, calcification, relationship with surrounding blood vessels, lymph node metastasis and lung metastasis in the highest AUC of 0.935 (sensitivity: 90.16%, specificity: 88.89%). In addition, we incorporated splenic involvement and metastatic sub-diaphragmatic lymph node into Model 2 as a new predictive model 3 for differential diagnosis and found a significant improvement in the diagnostic performance of Model 3.ConclusionThe diagnostic model composed of 18F-FDG PET parameters is improving the differential diagnosis of invasive TETs and anterior mediastinal lymphomas.

Investigating comparative polymerase chain reaction for antigen receptor rearrangement analysis in different types of feline lymphoma samples.

Cats have the highest incidence of lymphoma among all animal species. Lymphoma accounts for 41% of all malignant tumors in cats and is responsible for 90% of hematopoietic tumors in felines. Biopsies are considered the gold standard for diagnosis. Polymerase chain reaction (PCR)-based clonality assessment of antigen receptor gene rearrangements can be a valuable complementary tool for identifying infiltrating B-and T-lymphocyte clones. Many studies have focused on intestinal cases but few have addressed mediastinal lymphoma. This study aims to: (1) investigate the clonality patterns of lymphoma samples from various anatomical sites, with a particular focus on mediastinal lymphoma, and (2) evaluate the sensitivity and specificity of the clonality analysis of pleural effusion samples in comparison with cytology, histology, immunohistochemistry, and immunocytochemistry for diagnosing mediastinal lymphoma. There were 82 cases, divided into 49 formalin-fixed and paraffin-embedded biopsy specimens (FFPE), 22 cell pellets, and 11 fresh tissue. This study examined the sensitivity and specificity of PCR for antigen receptor rearrangement (PARR) compared to immunohistochemistry (IHC) and immunocytochemistry. For T-cell receptor gamma chain genes, PARR demonstrated a sensitivity of 58.33% for both fresh tissue and FFPE samples, with a specificity of 100%. Cell pellet analysis exhibited a sensitivity of 64.71% and maintained 100% specificity. A combined analysis of fresh tissue and FFPE with cell pellets showed a sensitivity of 62.07%. For IGH, the sensitivity for fresh tissue and FFPE samples was 56.25%, while cell pellet analysis showed a sensitivity of 62.50%. When considering fresh tissue and FFPE samples, the sensitivity was 57.14%. In conclusion, molecular techniques have emerged as valuable tools for detecting lymphoma, especially in cases where traditional diagnostic methods yield inconclusive results, such as mediastinal lymphoma. While biopsy may not always be feasible, cytology and cell pellets obtained from pleural effusion offer alternative immunocytochemistry and molecular analysis samples, provided they are of sufficient quality and quantity. All sample types considered in this study were suitable for PARR to aid in cases with inconclusive results. Therefore, the sample selection should be tailored to the clinical situation.

Myocardial Infiltration in Primary Mediastinal B-Cell Lymphoma Detected by Cardiac Magnetic Resonance Imaging

Introduction: Cardiac involvement, particularly myocardial infiltration in primary mediastinal lymphoma, is a rare occurrence with an incidence of only 9% in known cases of primary malignancy. Neoplasm infiltration into the myocardium manifests through direct invasion, hematogenous spread, transvenous invasion through the great veins, or lymphangitic spreading in the mediastinal. Myocardial infiltration in lymphoma presents a grim prognosis and its treatment may be associated with specific risks, such as myocardial rupture. Various imaging modalities may detect cardiac involvement, with cardiac magnetic resonance (CMR) imaging considered the gold standard. CMR enables clear delineation of myocardial infiltration, making it valuable for local staging, pretreatment planning, and evaluating treatment response. Case Presentation: : A 37-year-old woman patient was diagnosed with primary mediastinal large B-cell lymphoma. Mild chest discomfort and shortness of breath were observed 3 months before hospital admission. A thorax CT scan showed a heterogeneous contrast-enhancing mass with a central necrotic area in the anterior mediastinum. Following thoracotomy and tumor debulking, the patient complained of severe crushing chest pain radiating to her back, accompanied by new T wave inversion on ECG and elevated cardiac troponin levels a week after surgery. Coronary angiogram results showed a normal coronary artery. Subsequent cardiac MRI showed tumor infiltration into the anterior pericardial space, as well as the myocardium of the left and right ventricles. Chemotherapy was promptly initiated, resulting in a gradual improvement of symptoms. Conclusions: In this study, we discuss the use of 3D-CRT in the re-irradiation of NPC with its limitation on obtaining optimum dose sculpture compared to more sophisticated and widely spread modalities like IMRT. However, with careful planning, we can still obtain optimum tumor dose, minimize OAR dose, and subsequently late toxicities that come after. We hope that this study can bring hope to centers with limited facilities, and we suggest further studies on reirradiation, especially in OAR dose tolerance guidelines.

Survival Patterns of Non-Randomized Patients in the IELSG37 Study: Deauville Score 4 Is Not Necessarily Associated with Poor Outcome in Primary Mediastinal Lymphoma

Background:Primary mediastinal B-cell lymphoma (PMBCL) is clinically and biologically distinct from other types of aggressive lymphoma, it is characterized by a bulky mediastinal mass and most commonly occurs in women between 30 and 40 years of age. Although consolidation radiotherapy (RT) has yielded extremely positive outcomes in PMBCL, it carries a higher risk of long-term complications. Consequently, there has been an ongoing debate regarding the necessity of RT in patients responding to frontline immunochemotherapy. Methods:In the IELSG37 study, PMBCL 530 patients were treated with rituximab- and doxorubicin-containing regimens; 98% had stage I-II. Their response was assessed by positron emission computed tomography (PET/CT); 268 achieved a complete metabolic remission (CMR) defined as Deauville score (DS) 1 to 3 according to the Lugano classification and were randomly allocated to observation or mediastinal RT. The primary analysis [Zucca et al. J Clin Oncol 2023; 41 (suppl 17): abs. LBA7505] has shown that patients in CMR can safely forgo RT. The 3-year overall survival (OS) rate was 99% irrespective of irradiation. RT provided only minimal benefit on progression-free survival (PFS), which was over 96% at 3 years in both arms. Here we present the outcome of the 262 patients who were not randomized and were managed according to the preference of their treating physician. Results:Median follow-up was 64 months (interquartile range [IQR], 49-69). Besides 230 patients failing frontline treatment (174 DS4 and 56 DS5), the non-randomized cohort also included 1 patient with DS2 (who refused randomization and received RT) and 31 patients with DS3 who were initially considered as partial responders before a protocol amendment that changed the definition of CMR from DS 1-2 to DS 1-3. Among these non-randomized patients with DS3, 27 had RT consolidation, 1 was only observed, 2 had salvage chemotherapy ± RT, and 1 had missing data due to consent withdrawal; their 3-year PFS was very close to the one of the randomized patients with DS3 (90 vs 92%, p=0.99). In the DS4 group, 12 patients were observed, 149 had only RT, and 13 had second-line chemotherapy, with (12) or without (1) autologous stem cell rescue, 8 of 13 also had RT. Among the patients with DS5, only 2 were observed, 32 had only RT, and 22 had second-line chemotherapy, with (15) or without (7) autologous stem cell rescue; 12 of them also had RT. The outcome of patients with DS4 was overlapping the one of the patients achieving a CMR, with 3-year PFS of 97.1% (95%CI 93-99) and 97.4% (95%CI 95-99), respectively, while patients with DS5 had a significantly poorer 3-year PFS (62.4%, 95%CI 48-74) [Figure1A]. The 3-year OS showed a similar trend (98% in patients with DS4, 99% in those randomized, and 78% in the DS5 group). Notably, compared to patients receiving consolidation RT alone or only observed, the residual lesions on post-immunochemotherapy PET/CT scans of patients with DS4 and DS5 who were treated more aggressively (with salvage chemotherapy ± autologous transplant and/or RT) displayed significantly higher tracer maximum standardized uptake value (SUVmax, median: 8.2, IQR 4.6-16.5 vs. 3.8, IQR 3.1-4.9; p<0.0001) and larger residual metabolic tumor volume (MTV, median: 18 ml, IQR 3-95 vs. 3.6, ml, IQR 1-10; p<0.0001). These patients had significantly worse outcomes compared to those who received consolidation RT or were observed only [Figure 1B]. Conclusions:Patients with DS4 had outcomes similar to those of patients achieving a CMR, indicating that this group may either include a significant number of “false-positive” cases with inflammatory uptake or that their residual disease is limited and can potentially be cured with consolidation RT. Patients with DS5 had a significantly poorer outcome, although nearly half of them did well with RT alone. It seems plausible that clinical condition of the patient and/or imaging features of the residual disease have influenced treatment choices in patients without CMR after frontline immunochemotherapy. Further studies are needed to investigate whether PET metrics and/or liquid biopsies can aid in personalizing treatment and identifying patients who could potentially avoid irradiation.

Results of an Italian Retrospective Clinical Experience on Mediastinal Gray Zone Lymphoma

Introduction and methods: Mediastinal gray zone lymphoma (GZL) emerged as a rare and challenging entity due to its high rate of pathological reclassification and heterogeneous clinical management. The bio-GZL2020 study was designed to centralize histological samples and clinical data of patients (pts) diagnosed with GZL between 2006 and 2020 in 16 Italian hematological centers. We here report the preliminary clinical results of this retrospective analysis. Results: Overall, we collected samples and clinical data of 68 pts with GZL. According to the 2022 WHO and ICC classifications we excluded nine pts for lacking mediastinal involvement, hence 59 pts were analyzed. Pts were mostly stage I-II (62.7%); 57.6% had a mediastinal bulky disease. The site of diagnostic biopsy was the mediastinum in 29 pts. Additional clinical characteristics at baseline are reported in Table 1. One patient died before the start of treatment and was excluded from survival analysis. First line chemotherapy (CHT) consisted in DA-EPOCH in 31 pts, CHOP-like regimens in 17 pts, ABVD in six pts, MACOP-B in three pts and DHAP in only one case. Eight pts did not receive rituximab with CHT (six ABVD pts, two CHOP-like pts). Dose escalation in R-DA-EPOCH was performed in 75% of pts, with 18 pts (64.3%) attaining level 3 or higher. Four advanced stage, high-risk pts received central nervous system prophylaxis. Twenty-two pts performed an interim PET-scan during first line therapy; data on Deauville score was available in 19 cases, with 9 pts obtaining a score 1-3. Restaging after first line CHT showed 37 pts in complete remission (CR; 63.8%), nine pts in partial remission (PR; 15.5%), five pts in stable disease (SD; 8.6%) and seven pts in progressive disease (PD; 12.1%). Thirty-one pts (53.4%) received a consolidative treatment (26 pts radiotherapy (RT) only, seven pts autologous transplant (ASCT) only, two pts both RT and ASCT). Restaging after first line consolidation showed 43 CR (74.1%), four PR (6.9%), two SD (5.2%) and eight PD (13.8%). Nineteen pts underwent a second line CHT, 16 of them with a platinum-based regimen; brentuximab vedotin, BeGEV and HyperCVAD were used in one patient each. Second line consolidation ASCT was performed in seven pts, while one received an allogeneic transplant. Of the 17 restaged pts after second line CHT seven were in CR, 10 were not responsive (four SD, six PD). Considering all salvage lines five pts received a checkpoint inhibitor, nine underwent brentuximab vedotin treatment. Overall survival (OS) was 86.9% at 5 years and 71.3% at 10 years; beta2-microglobulin (available only in 32 pts) and the response after first line therapy were associated to a statistically significant difference in OS in univariate analysis. Progression-free survival (PFS) was 61.9% at 5 and 10 years. The use of rituximab, the Deauville score 1-3 at interim PET during induction, and the response after first line therapy were associated to a statistically significant difference in PFS in univariate analysis. ABVD was associated to poorer results in terms of OS and PFS although no significant difference was observed. No statistically significant difference in term of PFS was observed between pts treated with intensified regimens (DA-EPOCH, MACOP-B, DHAP) and other treatments in first line. Excluding pts directly shifted to salvage therapy, consolidative RT after first line CHT showed no statistically significance in term of both OS and PFS. Conclusions: To our knowledge our study represents the largest retrospective data collection on GZL among hematological Italian centers. This preliminary analysis did not show a clear advantage of intensive therapies such as DA-EPOCH or MACOPB, while the positive prognostic role of rituximab was confirmed in PFS. The prognostic role of interim PET-CT scan seems interesting and should be evaluated in subsequent trials. Further refinement of the reported results is expected in relation of an ongoing central pathological review by a panel of expert hematopathologists.

Radiotherapy Consolidation Reduces Risk of Relapse in Diffuse Large B-Cell Lymphoma Patients with Bulky Disease in Complete Response after Frontline Immunochemotherapy: Results from a Retrospective Single Center Study

INTRODUCTION: The role of radiotherapy (RT) consolidation upfront in patients with diffuse large B-cell lymphoma (DLBCL) and bulky disease at diagnosis is controversial, especially in those in complete response (CR) after immunochemotherapy. METHODS: All patients with DLBCL diagnosed between January 2010 and June 2021 at AOU Città della Salute e della Scienza di Torino and treated frontline with RCHOP-like regimens were retrospectively selected. Patients with primary mediastinal lymphoma were excluded. Clinical and biological features as well as treatment and survival data for the whole population were collected. All patients with bulky disease (defined as ≥6 cm) at diagnosis who obtained CR (defined as PET/TC Deauville score ≤ 3) at the end of systemic treatment were further selected. Progression free survival (PFS) and overall survival (OS) were compared between patients receiving consolidative RT on initial bulky mass and those who did not. RESULTS: A total of 453 patients with DLBCL were identified. Median age was 68 years (IQR 58-77), 56% were males, 74% stage ≥3, 52% IPI ≥3. 140/451 (31%) had bulky disease at diagnosis. Median follow-up was 5 years. 5-year PFS and OS for the whole cohort were 59% and 66%, respectively. Bulky disease correlated with a significantly lower 5-year PFS (bulky 50% vs no bulky 64%, p = 0.0005) and OS (bulky 68% vs no bulky 60%, p = 0.01). 82 out of 140 patients with bulky disease (68/82 with a bulky ≥7 cm) were in CR after immunochemotherapy: 19/82 (23%) received RT (16/19 on bulky ≥7 cm), 63/82 (77%) did not (55/63 with a bulky ≥7 cm). There were no significant differences between the two groups regarding age, stage, ECOG PS, LDH levels, extranodal involvement and IPI. RT dose was 30 Gy in most patients (17/19); two patients received 36 Gy and 40 Gy. The 5-year PFS was 95% in the RT cohort and 58% in the no-RT cohort (p = 0.004); the 5-y OS was 95% in the RT cohort and 69% in the no-RT cohort (p = 0.038) (figure 1). A propensity score matching analysis confirmed the benefit of RT on PFS (HR 0.1, 95% CI 0.01-0.68, p = 0.019), and showed a non-statistically significant trend of better OS (p = 0.06). 14/24 relapses in the no-RT cohort occurred on the site of bulky disease. CONCLUSIONS: With the limit of a non-randomized retrospective study, our data showed a benefit of RT consolidation on bulky disease in patients with DLBCL in RC after frontline immunochemotherapy, significantly prolonging PFS and with a trend of improved OS in a propensity score matching analysis.

A Randomized, Open-Label, Phase 3 Study of Acalabrutinib in Combination with Rituximab and Reduced Dose CHOP (R-miniCHOP) in Older Adults with Untreated Diffuse Large B-Cell Lymphoma (ARCHED / GLA 2022-1)

Background Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma subtype, and its incidence increases with age. Approximately 40% of patients with DLBCL are older than 70 years. Since the addition of the anti-CD20 antibody rituximab to CHOP regime (cyclophosphamide, doxorubicin, vincristine, and prednisone) prognosis in elderly patients has improved but still remains worse compared to their younger counterparts. Adequate dosage of chemotherapy in older adults is limited by comorbidities/frailty, especially in patients >80 years of age. An attenuated chemotherapy regimen, R-miniCHOP, has been evaluated in prospective trials and seems to provide a good balance between safety and efficacy in this vulnerable patient population (Peyrade et al, 2011). However, even with this regime, outcomes remain modest with 2-year overall survival at 50-60%, underlining the need for more effective treatment in this population. Acalabrutinib is a selective, irreversible, second-generation small molecule inhibitor of Bruton Tyrosine Kinase (BTK) with a more favorable safety profile compared to first generation BTK inhibitors. Although, not yet approved for the treatment of DLBCL, acalabrutinib showed promising results both as a single agent (Strati et al, Haematologica 2021) and in combination with full dose R-CHOP (Davies et al, ASH 2022), in patients aged up to 80 years. Furthermore, acalabrutinib carries the potential of improved efficacy in specific subgroups. The activated B-cell like (ABC) DLBCL subtype has been shown to depend on chronic active B-cell receptor signaling involving many downstream kinases including BTK. Additionally, the genetically defined subgroups MCD/C5, N1, and BN2/C1 and also may serve as potential predictive biomarkers for acalabrutinib. Study design and endpoints ARCHED is an investigator initiated, randomized, multicenter, open-label, phase III trial of R-miniCHOP with or without acalabrutinib in older adults with untreated DLBCL. Patients in the standard arm will receive 6 cycles of R-miniCHOP every 21 days followed by 2 cycles of rituximab alone, while patients in the experimental arm will receive the same regimen and additionally acalabrutinib 100 mg p.o. twice daily from day 1 to day 21 for 8 cycles (Figure 1). The primary endpoint of the study is investigator assessed progression-free survival (PFS). Secondary endpoints include overall survival, PFS per blinded independent review, event-free survival, outcomes according to cell of origin and molecular genotype, response rates, duration of response, progression, relapse and central nervous system (CNS) relapse rates as well as toxicity. Key eligibility criteria Patients are eligible for enrolment if they are >80 years old or >60 years old and ineligible for full-dose R-CHOP according to investigator assessment after standardized simplified geriatric evaluation and are diagnosed with untreated CD20+ DLBCL according to the 2017 WHO classification. Primary mediastinal lymphoma, high grade B-cell lymphoma and follicular lymphoma 3B as well as concurrent diagnosis of indolent lymphoma is allowed, but Richter's transformation is an exclusion criterion. Ann Arbor stage I patients can be included only in the presence of concomitant bulky disease (≥ 7.5 cm). Further exclusion criteria are CNS involvement, stroke or intracranial hemorrhage in the past 6 months and relevant organ dysfunction. An ECOG performance status score of 0 - 2 is required for enrolment but an ECOG score of 3 is acceptable if lymphoma associated. Statistical analysis With an expected 5% drop out rate, we aim to recruit 330 patients (165 in each arm) to achieve 80 % power at a 5 % significance level (two-sided) to observe a PFS difference of 15 % in favor of the experimental arm. An interim analysis for efficacy comparing PFS between the two treatment arms will be performed with n=200 patients and 1 year follow-up for the last patient, with approximately 50% of events. Additionally, an interim analysis for safety regarding treatment completion rates and all-cause mortality will take place when 92nd patient in each group has completed the sixth R-mini-CHOP cycle or died. ARCHED is an academic study of the German Lymphoma Alliance and is coordinated by the Saarland University Clinical Trials Unit. This study is funded by AstraZeneca GmbH. The trial is approved in the EU and is open for recruitment in Germany. (EU-CTN: 2022-501187-18-00, NCT05820841).

Autologous Transplant (auto-HCT) Is Associated with Improved Clinical Outcomes Compared to CAR-T Therapy in Patients (pts) with Large B-Cell Lymphoma (LBCL) Achieving a Complete Remission

Introduction: CAR-T therapy is the standard of care for pts with relapsed LBCL as early as in the second line in those with early relapse or with primary refractory disease. In practice, pts who are intended to receive CAR-T, commonly require interim therapy before leukapheresis, wherein a small fraction may achieve a complete remission (CR). Having chemosensitive disease, these pts can be considered for auto-HCT. Also, there are reports indicating the efficacy of CAR-T therapy in CR pts (Strati et al., Haematologica, 2023; Wudhikarn et al., Blood Adv, 2022). We compared the outcome of pts with LBCL who received CAR-T vs. auto-HCT while in a CR. Methods: Pts aged 18-75 years with DLBCL or primary mediastinal lymphoma who received CAR-T (between 2018-2021) or auto-HCT (between 2015-2021) while in a CR by PET or CT were included in this analysis using the data from the Center for International Blood & Marrow Transplant Research (CIBMTR) registry. Primary endpoints included progression-free survival (PFS) and overall survival (OS). Treatment-related mortality (TRM) and relapse rate were among the secondary endpoints. Results: We identified 360 pts with LBCL who were in a CR before receiving CAR-T (n=79, tisa-cel 53%, axi-cel 46%, and liso-cel 1%) or auto-HCT (n=281). Median follow-up was 24.7 months (range 3.3-49.4) for the CAR-T cohort and 49.7 months (range 3.0-95.4) for the auto-HCT cohort. Selected baseline characteristics are shown in Table 1. CRs were confirmed by PET scan in 90% of CAR-T pts and 99.6% of auto-CAR-T pts (p < 0.01). The most common lymphodepletion regimen for CAR-T was Cy/Flu (82.3%) and the most common conditioning regimen for auto-HCT was BEAM (77.6%). Thirty-seven (13.2%) of auto-HCT pts had a later CAR-T but no pts from the CAR-T cohort had subsequent auto-HCT. In univariate analysis, treatment with CAR-T was associated with a higher rate of relapse at 2 years (48% vs. 27.8%; p < 0.001), a lower rate of 2-year PFS (47.8% vs. 66.2%; p < 0.001) and lower 2-year OS (65.6% vs. 78.9%; p=0.037). There was no difference in rates of 2-year TRM (4.1% vs. 5.9%; p=0.673). Similarly, focusing on patients with early (12 months) treatment failure (CAR-T =57 and auto-HCT=163), treatment with CAR-T was associated with a higher 2-year relapse rate (45.9% vs. 22.8%; p <0.001) and an inferior 2-year PFS (48.3% vs.70.9%.; p <0.001) compared to auto-HCT (figure-2) while there was no difference in 2-year OS or TRM. In the multivariable analysis of outcomes, treatment with CAR-T was associated with higher risk of relapse (HR 2.18; p < 0.0001) and an inferior PFS (HR 1.83; p=0.0011) compared to auto-HCT. There was no difference in the risk of TRM (HR 0.59; p=0.36) or OS (HR 1.44; p=0.12). Conclusions: In pts with relapsed LBCL who achieve a CR, treatment with auto-HCT is associated with a lower relapse rate and an improved PFS compared to CAR-T, including in pts with early treatment failure (within 12 months). These results are in line with previously reported improved clinical outcomes with auto-HCT compared to CAR-T in pts in partial remission (Shadman et al. Blood, 2022). The data support utilization of auto-HCT in pts with relapsed LBCL achieving a CR.

Immunoglobulin light chain transcript detection by ultrasensitive RNA in situ hybridization for B-cell lymphoma diagnosis.

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.

The pathobiology of select adolescent young adult lymphomas.

Lymphoid cancers are among the most frequent cancers diagnosed in adolescents and young adults (AYA), ranging from approximately 30%-35% of cancer diagnoses in adolescent patients (age 10-19) to approximately 10% in patients aged 30-39 years. Moreover, the specific distribution of lymphoid cancer types varies by age with substantial shifts in the subtype distributions between pediatric, AYA, adult, and older adult patients. Currently, biology studies specific to AYA lymphomas are rare and therefore insight into age-related pathogenesis is incomplete. This review focuses on the paradigmatic epidemiology and pathogenesis of select lymphomas, occurring in the AYA patient population. With the example of posttransplant lymphoproliferative disorders, nodular lymphocyte-predominant Hodgkin lymphoma, follicular lymphoma (incl. pediatric-type follicular lymphoma), and mediastinal lymphomas (incl. classic Hodgkin lymphoma, primary mediastinal large B cell lymphoma and mediastinal gray zone lymphoma), we here illustrate the current state-of-the-art in lymphoma classification, recent molecular insights including genomics, and translational opportunities. To improve outcome and quality of life, international collaboration in consortia dedicated to AYA lymphoma is needed to overcome challenges related to siloed biospecimens and data collections as well as to develop studies designed specifically for this unique population.

Efficacy of COP-based protocol used with raltegravir in treatment of cats with mediastinal lymphoma and progressive viral leukemia

Mediastinal lymphoma is a common disease in both human and veterinary medicine and is frequently diagnosed in cats infected with feline leukemia virus. The disease is considered a negative prognostic factor for affected animals. The retrospective research included 5 FeLV-positive cats with confirmed mediastinal lymphoma and progressive viral leukemia. The purpose was to study the response of FeLV-positive cats to standard chemotherapy protocol: cyclophosphamide 250 mg/m2 IV, vincristine 0.5 mg/m2 IV, prednisolone 2040 mg/m2 orally (COP), survival of animals and side effects associated with chemotherapeutic treatment. All studied cats received raltegravir (Isentress, MSD, USA) orally at a dose of 20 mg/kg every 12 hours. Improvement in clinical signs associated with mediastinal lymphoma was observed after the 3rd course of chemotherapy. The clinical response rate was 80 % (40 % full remission, 40 % partial remission, 20 % unchanged status). The average lifespan of FeLV-positive cats treated with chemotherapy for mediastinal lymphoma was 1091.2 days, with a maximum lifespan of 1364 days and a minimum lifespan of 775 days. Rate of clinical response, as well as lifespan expectancy of affected cats, was higher than in previous studies. This is probably due to raltegravir, which can reduce the viral load and thus control the course of progressive infection. Side effects were found in 100 % of FeLV-positive cats: with anorexia - in two animals (60 %), vomiting - in two (40 %), neutropenia - in four (80 %), thrombocytopenia - in all cats (100 %), anemia - in three (60 %) and azotemia - in one animal (20 %). Overall, the efficacy of the COP protocol was satisfactory, and chemotherapy treatment can be offered to owners of FeLV-positive cats with mediastinal lymphoma, if the owner is reluctant to opt for euthanasia of the affected animal.

Giant middle mediastinal lesions: when tumor size correlates with mesenchymal origin-a retrospective single-center analysis.

The International Thymic Malignancy Interest Group (ITMIG) proposed an internationally accepted division of the mediastinum into three compartments based on computed tomography (CT): anterior (prevascular), middle (visceral) and posterior (paravertebral) compartment. There is no generally accepted definition for the term "giant" when applied to middle mediastinal lesions. We defined the term "giant" and described our surgical experience in treating patients with giant lesions of the middle mediastinum. CT imaging of patients operated in our center from January 2016 to August 2021 for mediastinal lesions was reviewed. Lesions were categorized to one of the ITMIG-defined compartments. Lesion size at diagnosis was measured at its largest diameter on axial CT imaging. Giant middle mediastinal lesions were defined as lesions having a size ≥90th percentile of our middle mediastinal lesion cohort. Patients with giant middle mediastinal lesions were further analyzed. Thirty-six patients (23%) had lesions located in the middle mediastinal compartment. Most common diagnoses were mediastinal cysts (n=10, 28%), metastatic lesions (n=6, 17%), lymphomas (n=5, 14%), and sarcomas (n=3, 8%). Ninetieth percentile lesion size was 73 mm. As per definition, four patients had giant middle mediastinal lesions. All these four lesions were of mesenchymal origin including oesophageal leiomyoma, synovial sarcoma, leiomyosarcoma and undifferentiated round cell sarcoma. Resection was performed through posterolateral thoracotomy or sternotomy, with or without cardiopulmonary bypass. The term "giant" could be defined as a mass larger or equal to 73 mm. This definition selected specifically lesions with mesenchymal origin and may therefore guide diagnostic algorithm and patient management.

POSTER: ABCL-176 New Strategy of First-line Treatment of Primary Mediastinal Lymphoma (PML): One Center Experience

POSTER: ABCL-176 New Strategy of First-line Treatment of Primary Mediastinal Lymphoma (PML): One Center Experience

ABCL-176 New Strategy of First-Line Treatment of Primary Mediastinal Lymphoma (PML): One Center Experience

ABCL-176 New Strategy of First-Line Treatment of Primary Mediastinal Lymphoma (PML): One Center Experience

Differentiating thymic epithelial tumors from mediastinal lymphomas: preoperative nomograms based on PET/CT radiomic features to minimize unnecessary anterior mediastinal surgery.

Clinical feasibility nomograms were developed to facilitate the differentiation between thymic epithelial tumors (TETs) and mediastinal lymphomas (MLs), aiming to minimize the occurrence of non-therapeutic thymectomy. A total of 255 patients diagnosed with TETs or MLs underwent pre-treatment 18F-FDG PET/CT. Comprehensive clinical and imaging data were collected, including age, gender, lactate dehydrogenase (LDH) level, pathological results, presence of myasthenia gravis symptoms, B symptoms, mass size, location, morphology, margins, density, and metabolic parameters derived from PET/CT. Radiomic features were extracted from the region of interest (ROI) of the primary lesion. Feature selection techniques were employed to identify the most discriminative subset of features. Machine learning methods were utilized to build candidate models, which were subsequently evaluated based on their area under the curve (AUC). Finally, nomograms were constructed using the optimal model to provide a clinical tool for improved diagnostic accuracy. The performance of the radiomic models was evaluated by their calibration, discrimination, and clinical utility. Several independent risk factors were identified for distinguishing TETs from MLs, including average standardized uptake value (SUVavg), LDH, age, mass size, and radiomic score (rad-score). Significance was observed in differentiating the two types of tumors based on these factors. The best clinical efficacy was demonstrated by the combined model, with an impressive AUC of 0.954. Decision curve analysis and calibration curves indicated that the combined model was clinically advantageous for discriminating TETs from MLs. Besides, the results of external validation showed a sensitivity of 0.8 and a specificity of 0.78. Preoperatively, the differentiation of TETs from MLs can be facilitated by the utilization of the combined clinical information and radiomics model. This approach holds promise in minimizing the occurrence of unnecessary anterior mediastinal surgeries.

An unevaluated case of massive mediastinal lymphoma for anesthesia-STRIVE-Hi to the rescue.

An unevaluated case of massive mediastinal lymphoma for anesthesia-STRIVE-Hi to the rescue.

Mediastinal Gray-Zone Lymphoma: Still an Open Issue

The concept of gray-zone lymphoma (GZL) has been progressively refined since its introduction in the literature in 1998. For several years, it was applied to a rather broad spectrum of conditions, posing the problem of the differential diagnosis between any type of Hodgkin lymphoma (HL) and diffuse large B-cell lymphoma, with special reference to primary mediastinal forms (PMBL). Officially recognised as a provisional entity in the 4th and revised 4th editions of the WHO Classification of Tumour of Haematopoietic and Lymphoid Tissues with the term “B-cell lymphoma unclassifiable with features intermediate between diffuse large B-cell lymphoma and classic Hodgkin lymphoma”, it was limited to tumours showing either morphologic features reminiscent of classic HL (CHL) but carrying a complete B-cell phenotype or conversely provided with a PMBL morphology yet revealing CHL phenotypic characteristics. The definition of GZL has been further revised in the recently published International Lymphoma Classification and 5th edition of the WHO Classification of Haematolymphoid Tumours, which have limited it to mediastinal neoplasms (MGZL) based on emerging molecular evidence. The aim of this review is to critically discuss the issue of MGZL, as well as in light of the suboptimal response to current therapies.

CNS RELAPSE OF DIFFUSE LARGE B‐CELL LYMPHOMA AND ROLE OF UPFRONT PROPHYLAXIS: A 10‐YEAR SINGLE CENTER EXPERIENCE

Introduction: Central nervous system (CNS) relapse of diffuse large B-cell lymphoma (DLBCL) is a rare event, occurring in about 5% of patients (pts) and correlating with a very dismal prognosis. Much debate has surrounded the use of strategies to avert CNS disease recurrence. Nowadays, CNS prophylaxis is mostly based on high-dose intravenous (iv) methotrexate (HD-MTX), but its effectiveness is controversial. Our study focuses on pts with CNS relapse of DLBCL in order to evaluate their clinical and biological features, the validity of known prognostic scores, the efficacy of CNS prophylaxis, prognosis and treatment at the time of relapse. Methods: All pts with DLBCL diagnosed between January 2010 and December 2021 at AOU Città della Salute e della Scienza di Torino and treated with curative intent were selected: 498 cases with at least 12 months of follow-up were identified. Pts with primary mediastinal lymphoma, primary testicular lymphoma or CNS disease at diagnosis were excluded. Results: The case series included 406 pts. Mean age was 67 years, 56/400 had ECOG PS ≥ 2 (14%), 231/400 elevated LDH levels (58%), 251/404 were stage IV (62%), 192/374 IPI score ≥ 3 (51%), 189/373 CNS-IPI 2–3 (51%), 91/373 CNS-IPI 4–6 (24%). 95/397 pts received CNS prophylaxis (24%): 59 by intrathecal (IT) route only (15%) (n 26 CNS-IPI 2-3; n 29 CNS-IPI 4-6), 25 by iv MTX only (6%) (n 17 HD-MTX ≥3 g/mq; n 6 CNS-IPI 2-3; n 16 CNS-IPI 4-6), and 11 by combined route (3%) (n 5 CNS-IPI 2-3, n 6 CNS-IPI 3–6). 12 pts experienced CNS relapse; 8/12 exclusively CNS and 4/12 along with systemic recurrence. The cumulative incidence at 3 years was 2.8%. In univariate analysis CNS relapse risk was significantly influenced by ECOG PS and elevated LDH levels, while the use of prophylaxis was not shown to impact the risk of CNS recurrence. However, none of the pts who received systemic MTX prophylaxis had subsequent CNS disease, while 2/59 pts who received exclusive IT prophylaxis had CNS relapse with an incidence superimposable to the whole cohort (3.3%). In multivariate analysis, only ECOG PS confirmed significant correlation with the risk of such disease recurrence (Figure 1). With a mean follow-up of 36 months, the 3-year overall survival for pts with SNC recurrence was 30%. Encore Abstract—previously submitted to EHA 2023 Keyword: aggressive B-cell non-Hodgkin lymphoma No conflicts of interests pertinent to the abstract.

Mediastinal gray zone lymphoma in a pregnant woman presenting with cardiac tamponade

BackgroundMediastinal gray zone lymphoma is a newly recognized rare B cell neoplasm, which is challenging in diagnosis and treatment.Case presentationIn the current study, we aimed to report a 25-year-old pregnant woman at 25 weeks of gestation who presented with chronic cough and progressive shortness of breath, hypotension, tachycardia, and tachypnea. A large circumferential pericardial effusion with compressive effect on the right atrium and right ventricle and a large extracardiac mass with external pressure to mediastinal structures were seen on trans thoracic echocardiography. The emergency pericardiocentesis was performed with the diagnosis of cardiac tamponade. Also, CMR revealed a huge heterogeneous anterior mediastinal mass, and the pathology and the immunohistochemistry of the mass biopsy revealed gray zone lymphoma with positive CD3, CD20, CD30, CD45, PAX5, and negative CD15 expression. Three courses of chemotherapy with the CHOP regimen were performed with an acceptable response every three weeks before delivery. A caesarian section was performed at 37 weeks without any problem for the patient and fetus, and chemotherapy will be started three weeks after delivery.ConclusionCardiac tamponade as an emergency condition occurred in this pregnant patient by malignant pericardial effusion and mediastinal mass pressure. Accurate diagnosis and on time interventions caused a significant improvement and a successful delivery.

Efficacy of Residual Site Radiation Therapy (ISRT) in Patients with Primary Mediastinal Lymphoma with Deauville Score 4 Following R-CHT: Results of a Retrospective Mono Institutional Study.

In order to evaluate the efficacy of residual site radiation therapy (RSRT) in terms of progression-free survival (PFS) and overall survival (OS) in patients with primary mediastinal lymphoma (PMBCL) with Deauville Score 4 (DS 4) following rituximab and chemotherapy treatment (R-ICHT). Thirty-one patients with PMBCL were recruited. After completion of R-ICHT, patients were staged with 18F-fluorodeoxyglucose positron-emission tomography, showing DS 4, and were treated with adjuvant RSRT. The chosen techniques for RT delivery were intensity-modulated radiation therapy (IMRT) or three-dimensional conformal RT (3D-CRT). Most patients underwent the first one using cone-beam computed tomography (CBCT). All patients were evaluated every 3 months for the first 2 years and every 6 months afterwards for a period of at least 5 years, with clinical and radiological procedures as required. All patients received RSRT with a dose of 30 Gy in 15 fractions. The median follow-up time of 52.7 months (IQR: 26-64.1 months). The 5-year OS rate was 100%. The 2-year and 5-year PFS rates were 96.7% and 92.5%, respectively. Patients with relapsed disease had been treated with high-dose chemotherapy (HDC) and autologous stem cell transplantation (auto-SCT). RSRT in patients with PMBCL treated with ICHT and DS 4 did not impact unfavorably on patient survival.