Laryngeal EBV-positive Inflammatory Follicular Dendritic cell/fibroblastic Reticular cell Tumour.

Epstein-Barr virus-positive Inflammatory follicular dendritic cell/fibroblastic reticular cell tumour (EBV-IFDC/FRCT) is a rare neoplasm that occurs almost exclusively in the liver or spleen. Extra-hepatosplenic presentation is infrequent and exceptional cases have been described arising in the gastrointestinal tract or in the pharynx. However, EBV-IFDC/FRCT cases have not been previously reported in the larynx. This report describes a case of a 32-year-old woman who arrived to the emergency department due to progressive dyspnea with associated inspiratory stridor and non-productive cough. Direct laryngoscopy showed a nodular tumour arising on the left posterior subglottic mucosa obstructing 90% of the airway. A preoperative dual energy contrast enhanced computed tomography (CECT) was performed demonstrating a low attenuation lesion on virtual non-contrast (VNC) images and vivid iodine uptake on the iodine map. The tumour was excised and the histopathological analysis led to the diagnosis of an EBV-IFDC/FRCT. A fibre-optic laryngoscopy six months after the surgery did not show any abnormalities. Although the vast majority of EBV-IFDC/FRCT occur in the liver or spleen, some extra hepatosplenic tumours have been reported affecting the head and neck region. We describe here the first case arising in the larynx, as well as the usefulness of preoperative dual energy imaging techniques to assess these lesions, thus providing information that could have management implications.

Decoding the molecular heterogeneity of pediatric monomorphic post-solid organ transplant lymphoproliferative disorders.

Posttransplant lymphoproliferative disorders (PTLDs) represent a broad spectrum of lymphoid proliferations, frequently associated with Epstein-Barr virus (EBV) infection. The molecular profile of pediatric monomorphic PTLDs (mPTLDs) has not been elucidated, and it is unknown whether they display similar genetic features as their counterpart in adult and immunocompetent (IMC) pediatric patients. In this study, we investigated 31 cases of pediatric mPTLD after solid organ transplantation, including 24 diffuse large B-cell lymphomas (DLBCLs), mostly classified as activated B cell, and 7 cases of Burkitt lymphoma (BL), 93% of which were EBV positive. We performed an integrated molecular approach, including fluorescence in situ hybridization, targeted gene sequencing, and copy number (CN) arrays. Overall, PTLD-BL carried mutations in MYC, ID3, DDX3X, ARID1A, or CCND3 resembling IMC-BL, higher mutational burden than PTLD-DLBCL, and lesser CN alterations than IMC-BL. PTLD-DLBCL showed a very heterogeneous genomic profile with fewer mutations and CN alterations than IMC-DLBCL. Epigenetic modifiers and genes of the Notch pathway were the most recurrently mutated in PTLD-DLBCL (both 28%). Mutations in cell cycle and Notch pathways correlated with a worse outcome. All 7 patients with PTLD-BL were alive after treatment with pediatric B-cell non-Hodgkin lymphoma protocols, whereas 54% of patients with DLBCL were cured with immunosuppression reduction, rituximab, and/or low-dose chemotherapy. These findings highlight the low complexity of pediatric PTLD-DLBCL, their good response to low-intensity treatment, and the shared pathogenesis between PTLD-BL and EBV-positive IMC-BL. We also suggest new potential parameters that could help in the diagnosis and the design of better therapeutic strategies for these patients.

Intravascular Large B-Cell Lymphoma Genomic Profile Is Characterized by Alterations in Genes Regulating NF-κB and Immune Checkpoints.

Intravascular large B-cell lymphoma (IVLBCL) is an uncommon lymphoma with an aggressive clinical course characterized by selective growth of tumor cells within the vessels. Its pathogenesis is still uncertain and there is little information on the underlying genomic alterations. In this study, we performed a clinicopathologic and next-generation sequencing analysis of 15 cases of IVLBCL using a custom panel for the detection of alterations in 68 recurrently mutated genes in B-cell lymphomagenesis. Six patients had evidence of hemophagocytic syndrome. Four patients presented concomitantly a solid malignancy. Tumor cells outside the vessels were observed in 7 cases, 2 with an overt diffuse large B-cell cell lymphoma. In 4 samples, tumor cells infiltrated lymphatic vessel in addition to blood capillaries. Programmed death-ligand 1 (PD-L1) was positive in tumor cells in 4 of 11 evaluable samples and in macrophages intermingled with tumor cells in 8. PD-L1 copy number gains were identified in a higher proportion of cases expressing PD-L1 than in negative tumors. The most frequently mutated gene was PIM1 (9/15, 60%), followed by MYD88L265P and CD79B (8/15, 53% each). In 6 cases, MYD88L265P and CD79B mutations were detected concomitantly. We also identified recurrent mutations in IRF4 , TMEM30A , BTG2 , and ETV6 loci (4/15, 27% each) and novel driver mutations in NOTCH2 , CCND3 , and GNA13 , and an IRF4 translocation in 1 case each. The mutational profile was similar in patients with and without evidence of hemophagocytic syndrome and in cases with or without dissemination of tumor cells outside the vessels. Our results confirm the relevance of mutations in B-cell receptor/nuclear factor-κB signaling and immune escape pathways in IVLBCL and identify novel driver alterations. The similar mutational profile in tumors with extravascular dissemination suggests that these cases may also be considered in the spectrum of IVLBCL.

Diffuse large B-cell lymphomas in adults with aberrant coexpression of CD10, BCL6, and MUM1 are enriched in IRF4 rearrangements.

Diffuse large B-cell lymphoma (DLBCL) with aberrant coexpression of CD10+BCL6+MUM1+ (DLBCL-AE), classified as germinal center B cell (GCB) type by the Hans algorithm (HA), was genetically characterized. To capture the complexity of DLBCL-AE, we used an integrated approach that included gene expression profiling (GEP), fluorescence in situ hybridization, targeted gene sequencing, and copy number (CN) arrays. According to GEP, 32/54 (59%) cases were classified as GCB-DLBCL, 16/54 (30%) as activated B-cell (ABC) DLBCL, and 6/54 (11%) as unclassifiable. The discrepancy between HA and GEP was 41%. Three genetic subgroups were identified. Group 1 included 13/50 (26%) cases without translocations and mainly showing and ABC/MCD molecular profile. Group 2 comprised 11/50 (22%) cases with IRF4 alterations (DLBCL-IRF4), frequent mutations in IRF4 (82%) and NF-κB pathway genes (MYD88, CARD11, and CD79B), and losses of 17p13.2. Five cases each were classified as GCB- or ABC-type. Group 3 included 26/50 (52%) cases with 1 or several translocations in BCL2/BCL6/MYC/IGH, and GCB/EZB molecular profile predominated. Two cases in this latter group showed complex BCL2/BCL6/IRF4 translocations. DLBCL-IRF4 in adults showed a similar copy number profile and shared recurrent CARD11 and CD79B mutations when compared with LBCL-IRF4 in the pediatric population. However, adult cases showed higher genetic complexity, higher mutational load with frequent MYD88 and KMT2D mutations, and more ABC GEP. IRF4 mutations were identified only in IRF4-rearranged cases, indicating its potential use in the diagnostic setting. In conclusion, DLBCL-AE is genetically heterogeneous and enriched in cases with IRF4 alterations. DLBCL-IRF4 in adults has many similarities to the pediatric counterpart.

Antiphospholipase A2 receptor antibody-positive membranous nephropathy in the kidney donor: Lessons from a serendipitous transplantation.

Primary membranous nephropathy (PMN) is an autoimmune disease limited to the kidney that is characterized by the presence of circulating PLAR2 antibodies in 70% of the cases and usually positivity for PLA2R and IgG4 by immunohistochemistry (IHC) staining. We report the first documented case of PMN (PLA2R positive) in a deceased kidney donor, transplanted to two different recipients and their clinical and immunological evolution through serial biopsies. Recipient A's first allograft biopsy (Day 26) was compatible with a MN with both positive PLA2R and IgG4 subepithelial deposits in IHC. The donor's preimplantation kidney biopsies were retrieved and reexamined, revealing MN, with high intensity for PLA2R and IgG4 in IHC. Recipient B's protocol allograft biopsy, performed later at 3 months, also revealed histology compatible with MN but without the presence of PLA2R nor IgG4 in IHC. At 1-year follow-up, both recipients maintain graft function. Serial protocol biopsies were performed in both patients showing disappearance of IgG4 in recipient A but the persistence of PLA2R in IHC. We can conclude that, given the reversal of PMN changes in the grafts, it could be considered to transplant a patient from an asymptomatic deceased donor with PMN as long as he maintains unaltered renal function.

Kidney Transplantation in Monoclonal Immunoglobulin Deposition Disease: A Report of 6 Cases.

Monoclonal immunoglobulin deposition disease (MIDD) usually leads to kidney failure. Treatment of patients with a bortezomib-based regimen followed by autologous stem cell transplantation (SCT) has been increasingly used, with improvements in the response rates and allograft outcomes in kidney transplant recipients. The objective of this report was to analyze the outcomes of 6 patients who underwent kidney transplantation in our institution after treatment of MIDD between 2010 and 2019. Monoclonal immunoglobulin deposition disease was initially treated with bortezomib-based therapy followed by high-dose melphalan and autologous SCT with complete hematologic response, although all patients remained on dialysis. During a median follow-up of 20.5 months from kidney transplant (54 months from SCT), 1 patient experienced hematologic relapse and 2 had hematologic progression (one of them with MIDD relapse in the allograft) requiring treatment. The patient with organ relapse received daratumumab monotherapy, achieving complete hematologic response but with graft failure. The other 5 patients had functional grafts with median serum creatinine 1.68 mg/dL. These results support that, in patients with MIDD and sustained complete hematologic response, a kidney transplant can be considered. The optimal approach to treatment of hematologic relapse or recurrence of MIDD after kidney transplant remains to be determined.

Mutational Landscape and Tumor Burden Assessed by Cell-free DNA in Diffuse Large B-Cell Lymphoma in a Population-Based Study.

PURPOSE: We analyzed the utility of cell-free DNA (cfDNA) in a prospective population-based cohort to determine the mutational profile, assess tumor burden, and estimate its impact in response rate and outcome in patients with diffuse large B-cell lymphoma (DLBCL). EXPERIMENTAL DESIGN: A total of 100 patients were diagnosed with DLBCL during the study period. Mutational status of 112 genes was studied in cfDNA by targeted next-generation sequencing. Paired formalin-fixed, paraffin-embedded samples and volumetric PET/CT were assessed when available. RESULTS: Appropriate cfDNA to perform the analyses was obtained in 79 of 100 cases. At least one mutation could be detected in 69 of 79 cases (87%). The sensitivity of cfDNA to detect the mutations was 68% (95% confidence interval, 56.2-78.7). The mutational landscape found in cfDNA samples was highly consistent with that shown in the tissue and allowed genetic classification in 43% of the cases. A higher amount of circulating tumor DNA (ctDNA) significantly correlated with clinical parameters related to tumor burden (elevated lactate dehydrogenase and ß2-microglobulin serum levels, advanced stage, and high-risk International Prognostic Index) and total metabolic tumor volume assessed by PET/CT. In patients treated with curative intent, high ctDNA levels (>2.5 log hGE/mL) were associated with lower complete response (65% vs. 96%; P < 0.004), shorter progression-free survival (65% vs. 85%; P = 0.038), and overall survival (73% vs. 100%; P = 0.007) at 2 years, although it did not maintain prognostic value in multivariate analyses. CONCLUSIONS: In a population-based prospective DLBCL series, cfDNA resulted as an alternative source to estimate tumor burden and to determine the tumor mutational profile and genetic classification, which have prognostic implications and may contribute to a future tailored treatment.