Demonstration of Chimeric DNA of bcl-2 and Immunoglobulin Heavy Chain in Follicular Lymphoma and Subsequent Hodgkin Lymphoma from the Same Patient

Classical Hodgkin lymphoma following follicular lymphoma: a case report

The simultaneous, composite, or sequential occurrence of follicular lymphoma (FL) and classical Hodgkin lymphoma (HL), both of which originate from germinal center B-cell, is rare. Questions have been raised with regard to the type of tests that pathologists should perform when observing the presence of a "large-cell lymphoma" following an FL and what are the most critical pathological points for diagnosis. Here, we present a case of a classical HL following an FL after administering rituximab-bendamustine (R-Benda) chemotherapy. Furthermore, we also summarized the literature and compared this case with other HLs that followed FLs. A 55-year-old woman was diagnosed with a grade 3A FL of the breast and axillary lymph node masses. She completed six R-Benda chemotherapy cycles for stage IV FL. Twenty-three months after the diagnosis, follow-up image studies showed an increase in the size and number of the lesions. Biopsies of the neck lymph node and liver were performed, and the diagnosis was classical HL. Sequential or composite FL and HL may sometimes develop from the same clone because they share the same genetic alterations, such as B-cell lymphoma (Bcl)-2 or Bcl-6 translocation. When a large-cell lymphoma is found after the treatment of FL, classical HL should be considered a pathological differential diagnosis, and histological, immunohistochemical, or molecular investigations must be considered during the diagnostic process.

Divergent evolution of metachronous follicular lymphoma and extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue from a common precursor

The translocation t(14;18)(q32:q21)/IGH::BCL2 occurs at the pre-B stage of B-cell development in the bone marrow and is insufficient for malignant transformation, although it leads to the formation of in situ follicular B-cell neoplasia (ISFN). Despite that, the translocation is the genetic hallmark of follicular lymphoma (FL), it occurs infrequently in metachronous/synchronous lymphomas, including extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (EMZL), mantle cell lymphoma, and Hodgkin's lymphoma. In each of these scenarios, the two lymphomas often appear to be clonally related by analyses of IGH::BCL2 and/or rearranged IG genes. However, it remains largely unknown whether one lymphoma originates from the other or they develop independently. We studied five cases of metachronous EMZL and FL. In four cases, the two lymphomas were clonally related, as shown by identical IGH::BCL2 and/or rearranged IG genes or shared mutations. There were common and unique mutations between the paired EMZL and FL, indicating that they developed independently from a common premalignant cell population, harbouring IGH::BCL2 in three cases. Furthermore, case 1 presented with three metachronous FLs, and all of them originated from a common precursor cell population via divergent evolution. Our findings highlight the multi-malignant potential of IGH::BCL2-positive B-cells. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Plasticity in Classical Hodgkin Composite Lymphomas: A Systematic Review

The co-occurrence of several lymphomas in a patient defines composite/synchronous lymphoma. A common cellular origin has been reported for both contingents of such entities. In the present review, we aimed to gather the available data on composite lymphomas associating a classical Hodgkin lymphoma (cHL) with another lymphoma, to better understand the plasticity of mature B and T-cells. This review highlights that >70% of patients with a composite lymphoma are ≥55 years old, with a male predominance. The most reported associations are cHL with follicular lymphoma or diffuse large B-cell lymphoma, with over 130 cases reported. The cHL contingent is often of mixed cellularity type, with a more frequent focal/weak CD20 expression (30% to 55.6%) compared to de novo cHL, suggesting a particular pathophysiology. Moreover, Hodgkin cells may express specific markers of the associated lymphoma (e.g., BCL2/BCL6 for follicular lymphoma and Cyclin D1 for mantle cell lymphoma), sometimes combined with common BCL2/BCL6 or CCND1 rearrangements, respectively. In addition, both contingents may share similar IgH/IgK rearrangements and identical pathogenic variants, reinforcing the hypothesis of a common clonal origin. Finally, cHL appears to be endowed with a greater plasticity than previously thought, supporting a common clonal origin and a transdifferentiation process during lymphomagenesis of composite lymphomas.

The EZH2 inhibitor tazemetostat upregulates the expression of CCL17/TARC in B-cell lymphoma and enhances T-cell recruitment

An inhibitor of the histone methyltransferase enhancer of zeste homologue 2 (EZH2), tazemetostat, has been developed for the treatment of B‐cell lymphoma, but its mechanisms of action are not fully elucidated. We screened for genes targeted by tazemetostat in eleven B‐cell lymphoma cell lines and found that tazemetostat significantly increased the expression of chemokine (C‐C motif) ligand 17 (CCL17)/thymus‐ and activation‐regulated chemokine (TARC) in all, which codes for a chemokine that is a hallmark of Hodgkin/Reed‐Sternberg (H/RS) cells in Hodgkin lymphoma. Notably, gene set enrichment analysis demonstrated a positive correlation between the genes upregulated by tazemetostat in five follicular lymphoma (FL) cell lines and those reported to be overexpressed in H/RS cells. The CCL17 promoter region was enriched in repressive histone modification H3K27me3, and tazemetostat induced H3K27 demethylation and activated gene transcription. CCL17 protein secretion was also induced by EZH2 inhibition, which was further enhanced by concurrent CpG stimulation. In vitro transwell migration assay demonstrated that CCL17 produced by tazemetostat‐treated B cells enhanced the recruitment of T cells, which had the potential to exert antilymphoma response. Analysis of publicly available human lymphoma databases showed that CCL17 gene expression was inversely correlated with the EZH2 activation signature and significantly paralleled the CD4⁺ and CD8⁺ T‐cell–rich signature in FL and germinal center B‐cell–like diffuse large B‐cell lymphoma. Our findings indicate that tazemetostat can potentially activate antilymphoma response by upregulating CCL17 expression in B‐cell lymphoma cells and promote T‐cell recruitment, which provides a rationale for its combination with immunotherapy.

Plasticity of Mature B Cells Between Follicular and Classic Hodgkin Lymphomas: A Series of 22 Cases Expanding the Spectrum of Transdifferentiation

Follicular lymphoma and classic Hodgkin lymphoma can be associated in composite and/or sequential lymphomas. Common IGH and BCL2 rearrangements have already been identified between both contingents of these entities, but mutation profiles have not yet been investigated. The main objective of this study was to analyze the transdifferentiation process that may occur between Hodgkin and follicular contingents in sequential and composite lymphomas to better characterize these entities. From 2004 to 2020, a retrospective multicentric study was performed, including 9 composite and 13 sequential lymphomas. Clinical data were retrospectively collected. Fluorescent in situ hybridization of BCL2 and BCL6 rearrangements, polymerase chain reaction of IGH and IGK rearrangements, next-generation sequencing of IGK rearrangement, and targeted next-generation sequencing (TNGS) on a panel of genes frequently mutated in lymphomas were performed on each contingent of composite and sequential lymphomas. For TNGS, each contingent was isolated by laser capture microdissection. Clinical presentation and evolution were more aggressive in sequential than composite lymphomas. By fluorescent in situ hybridization, common rearrangements of BCL6 and BCL2 were identified between both contingents. Similarly, a common clonal relationship was established by evaluating IGH and IGK rearrangement by polymerase chain reaction or next-generation sequencing. By TNGS, the same pathogenic variants were identified in both contingents in the following genes: CREBBP, KMT2D, BCL2, EP300, SF3B1, SOCS1, ARID1A, and BCOR. Specific pathogenic variants for each contingent were also identified: XPO1 for Hodgkin lymphoma contingent and FOXO1, TNFRSF14 for follicular lymphoma contingent. This study reinforces the hypothesis of a transdifferentiation process between Hodgkin and follicular contingent of sequential/composite lymphomas.

Classical Hodgkin lymphoma-type and monomorphic-type post-transplant lymphoproliferative disorder following liver transplantation: a case report

BACKGROUND

Post-transplant lymphoproliferative disorder (PTLD) is a life-threatening complication that can be difficult to treat; moreover, determination of the pathophysiological type is difficult. We report a rare case of a patient who developed two types of Epstein-Barr virus (EBV)-negative PTLD following living donor liver transplantation (LDLT).

CASE PRESENTATION

A 64-year-old man underwent LDLT for acute fulminant hepatitis B. Sixty-five months later, he developed EBV-negative monomorphic B cell PTLD. Reduction of immunosuppressive therapy and chemotherapy with rituximab resulted in a partial response. He received radioimmunotherapy with yttrium-90-ibritumomab tiuxetan, which was effective for all lesions, except for the splenic hilar lesion, which enlarged and seemed to penetrate the stomach. Therefore, he underwent resection of the pancreatic tail with splenectomy and partial gastrectomy. The pathological diagnosis was EBV-negative classical Hodgkin lymphoma (cHL)-type PTLD.

CONCLUSIONS

This patient showed an unexpected course of PTLD, from both a clinical and pathological perspective. There are no prior reports of an adult case of EBV-negative cHL-type PTLD coexisting with EBV-negative monomorphic B cell PTLD. When a strange and refractory lesion persists despite effective therapy for PTLD, we must consider the possibility of another type of PTLD within the residual lesion.

Three coexisting lymphomas in a single patient: composite lymphoma derived from a common germinal center B-cell precursor and unrelated discordant lymphoma

Composite lymphoma (CL) is a rare disorder defined as the coexistence of two or more distinct lymphoma subtypes at a single anatomic site. Discordant lymphoma (DL), which is the simultaneous occurrence of two or more distinct lymphoma subtypes at different sites, is also rare. CL complicated with DL involving three distinct subtypes of lymphoma in the same patient is an extremely rare disease. Clonal relationships in CL and DL are commonly investigated by molecular analysis using mutational status with t(14;18)BCL2/IgH translocation and immunoglobulin heavy chain variable-region (IgV_H) gene rearrangement. A 73-year-old woman was admitted to our hospital with systemic lymphadenopathy and was initially diagnosed with diffuse large B-cell lymphoma based on pathological features of the biopsied esophageal tumor. However, the results of inguinal lymph node biopsy led to a revised pathological diagnosis CL consisting of Hodgkin lymphoma and follicular lymphoma. Three distinct coexisting lymphomas were identified in this individual patient. Molecular analysis revealed CL derived from common germinal center B-cell precursors, while clonal relationship between CL and DL was not clarified. This case suggests a mechanism underlying B-cell lymphoma pathogenesis involving two pivotal somatic mutations, t(14;18)BCL2/IgH translocation and IgV_H rearrangement.

Classical Hodgkin Lymphoma Arising Adjacent to a Breast Implant

Breast implant–associated lymphoma has recently gained wide recognition. Anaplastic large cell lymphoma (ALCL) is the most frequently diagnosed subtype in this setting but the spectrum is broadening. A 66-year-old woman developed swelling and itch around her saline implant 6 years after its insertion. Imaging revealed a fluid collection surrounding the implant with an adjacent mass. Microscopy showed sclerotic tissue punctuated by discrete cellular nodules comprising small lymphocytes, eosinophils and interspersed large atypical Hodgkin Reed-Sternberg (HRS)-like cells. The HRS-like cells stained positively for CD30 and CD15 by immunohistochemistry. Small T-lymphocytes formed rosettes around HRS-like cells. Appearances were consistent with classical Hodgkin lymphoma (HL). Multiplex polymerase chain reaction demonstrated no clonal rearrangements of immunoglobulin or T-cell receptor genes, however, a t(14;18)(q32;q21)BCL2-JH translocation involving the major breakpoint region of the bcl2 gene was present. Staging positron emission tomography–computed tomography scan revealed FDG-avid masses in the right axilla and pelvis. Subsequent pathological examination identified low-grade follicular lymphoma (FL) with a t(14;18) translocation at these sites. To our knowledge, this is the first case of HL arising adjacent to a breast implant. An awareness of this diagnosis is important as classical HL, with its prominent mixed inflammatory background, may be overlooked as a reactive process when histologically assessing capsulectomy specimens. It is also important in the differential diagnosis for implant-associated ALCL as both contain large atypical CD30-positive cells highlighting the need for full immunohistochemical and molecular workup in such cases. This case also adds to the large body of literature regarding the association between HL and FL.

Discordant lymphoma consisting of mediastinal large B-cell lymphoma and nodular sclerosis Hodgkin lymphoma in the right supraclavicular lymph nodes: a case report

Background

Discordant lymphoma is defined by the simultaneous presence of two or more distinct types of lymphomas at different anatomic sites. With fewer than 20 studies reporting cases of discordant lymphoma to date, the incidence of this condition is believed to be very low.

Case Presentation

Here, we report a case of discordant lymphoma in a 34-year-old female patient that involved mediastinal large B-cell lymphoma and nodular sclerosis Hodgkin lymphoma in the right supraclavicular lymph nodes. The patient presented with a mass in the mediastinum and enlargement of the right supraclavicular lymph nodes, but no obvious signs of lymphoma. Histological examination revealed that the encapsulated mediastinal mass contained medium- or large-size tumor cells with lightly stained cytoplasm and round vesicular nuclei as well as a high percentage of mitotic cells; strongly positive immunohistochemical staining for PAX5, CD20, and CD79a also was observed. Examination of biopsied right supraclavicular lymph node tissues revealed separation by collagen fibers, extensive inflammatory cell infiltration, and large-size tumor cells, such as Reed–Sternberg cells. These tissues stained strongly positive for PAX5 and CD30, weakly positive for CD15, and negative for Epstein-Barr viral RNA. We also found monoclonal gene rearrangement in the immunoglobulin heavy chain gene in the mediastinal large B-cell lymphoma, but no monoclonal gene rearrangement in the nodular sclerosis Hodgkin lymphoma. These findings suggested that these two lymphomas were not of a common clonal origin. The patient was treated by surgical excision of the mediastinal mass followed by radio-chemotherapy, and no metastasis or recurrence occurred during a follow-up period of 32 months.

Conclusion

A review of previously reported cases indicated that the clinical manifestations and pathological features of discordant lymphoma are diverse due to variation in the types of lymphomas involved. Physicians must have an awareness of discordant lymphoma to avoid incorrect and missed diagnoses, especially considering that the true incidence may not be as low as previously believed.

Electronic supplementary material

The online version of this article (doi:10.1186/s13000-015-0450-6) contains supplementary material, which is available to authorized users.

Follicular lymphoma-like B cells of uncertain significance (in situ follicular lymphoma) may infrequently progress, but precedes follicular lymphoma, is associated with other overt lymphomas and mimics follicular lymphoma in flow cytometric studies

In situ follicular lymphoma, more recently known as follicular lymphoma-like B cells of uncertain/undetermined significance is well accepted. However, the morphological criteria have evolved since it was first described and data are limited and conflicting regarding its clinical implications and whether the extent of involvement predicts an association with overt lymphoma. It is also unknown how often it will be identified by flow cytometric studies and how often it precedes overt follicular lymphomas. A multiparameter study of 31 biopsies with follicular lymphoma-like B cells of uncertain significance and 4 'benign' lymph node biopsies that preceded an overt follicular lymphoma was, therefore, performed. Fifty-two percent of biopsies with follicular lymphoma-like B cells were associated with a prior or concurrent lymphoma but only 6% subsequently developed lymphoma (median follow up 26 months). Neither the number, proportion or density of BCL2(+) germinal centers were associated with overt follicular lymphoma/diffuse large B-cell lymphoma. Flow cytometric studies identified follicular lymphoma-like B cells in 8 of 15 evaluable cases. The proportion but not the absolute number of BCL2(+) germinal centers was associated with the likelihood of positive flow cytometric studies (P<0.01). All 4 'benign' biopsies that preceded an overt follicular lymphoma demonstrated follicular lymphoma-like B cells. Thus, although few patients with follicular lymphoma-like B cells of uncertain significance progress within the follow-up period, it at least precedes many follicular lymphomas. The extent of involvement does not predict the occurrence of prior or concurrent lymphomas. Flow cytometric studies demonstrating follicular lymphoma-like B cells must not be over-interpreted as they may only reflect follicular lymphoma-like B cells.

High frequency of t(14;18) in Hodgkin's lymphoma associated with follicular lymphoma

t(14;18) is a common cytogenetic abnormality in B-cell lymphoma, especially in follicular lymphoma (FL), but is rarely seen in Hodgkin's lymphoma (HL). However, due to the small number of cases, the incidence of t(14;18) in HL associated with FL remains unclear. In this study, we applied chromogenic in situ hybridization and fluorescence in situ hybridization for t(14;18) on paraffin-embedded tissue from four HL associated with FL cases and 11 HL cases without a history of FL for comparison. t(14;18) was present in all of the three successfully-tested HL associated with FL cases and one case without a history of FL. The frequency of t(14;18) was significantly high in HL associated with FL (p = 0.013). All Hodgkin's and Reed-Sternberg (HRS) cells having t(14;18) showed immunoreactivity for BCL2 and were negatively stained for nuclear factor-κB (NF-κB), even in Epstein-Barr virus (EBV)-infected cases. However, HRS cells without t(14;18) showed BCL2 and NF-κB immunoreactivity in 33% and 57% of cases, respectively. There was an inverse correlation between t(14;18) and NF-κB. In conclusion, we assume the incidence of t(14;18) in HL associated with FL is higher than previously believed and BCL2 expression derived from t(14;18) may play a role in the pathogenesis of HL associated with FL.