Composite and sequential lymphoma between classical Hodgkin lymphoma and primary mediastinal lymphoma/diffuse large B-cell lymphoma, a clinico-pathological series of 25 cases

Primary Refractory Discordant Diffuse Large B-Cell and Classical Hodgkin Lymphoma

Discordant lymphomas are defined as two or more distinct pathological lymphomas occurring in the same patient. Due to the rarity of discordant lymphomas, which is due in large part to the difficulty in establishing the diagnosis, the literature is limited to small case series and case reports. Consequently, guidelines on therapeutic strategies are lacking. This article presented a case of primary refractory discordant large B-cell lymphoma and classic Hodgkin lymphoma in a young man based on cervical node and mediastinal mass biopsy, respectively. This case illustrates the difficulty in establishing the diagnosis, which ultimately warranted a high index of clinical suspicion and pursuit of multiple sequential biopsies, as well as a novel treatment strategy using an immune checkpoint inhibitor.

Aggressive Mediastinal Lymphomas

The mediastinum contains essentially all major intrathoracic organs except for the lungs. A variety of both benign and malignant tumors can involve the mediastinum, of which lymphoma is the most common malignancy. Compared to secondary mediastinal involvement by systemic lymphomas, primary mediastinal lymphomas are less common with several specific entities that are mainly confined to mediastinal lymph nodes, and/or thymus. This review will summarize the clinical, histologic, immunophenotypic and molecular genetic features of the most common and most aggressive primary mediastinal lymphomas as well as provide suggested immunohistochemistry panels and differential diagnoses.

Brentuximab vedotin plus AVD followed by involved-node radiotherapy in a patient with classic Hodgkin lymphoma following gray zone lymphoma after autologous stem-cell transplantation failure

BACKGROUND

No consensus has been reached yet concerning treatment strategies for a sequential classic Hodgkin lymphoma (CHL) following gray zone lymphoma (GZL). Prognosis of GZL after a failed autologous hematopoietic stem-cell transplantation (auto-HCT) is poor and treatment strategy is very limited. As yet there are limited data showing clinical outcomes of brentuximab vedotin (BV) for GZL, especially for sequential CHL after GZL.

CASE PRESENTATION

We report a case of CHL following primary refractory GZL after a failed auto-HCT and showed favorable response to first-line CHL-directed chemoradiotherapy consisting of BV plus doxorubicin, vinblastine, and dacarbazin (AVD) followed by irradiation. The sequential cases with an early evolution, whose diagnosis of second lymphoma was made within a year, have been recently reported very poor survival shorter than a year. Whether a sequential CHL following GZL should be treated as a primary or relapsed disease has not been clearly elucidated. Our patient showed favorable response to first-line CHL-directed chemoradiotherapy without allogenic hematopoietic stem-cell transplantation and has in continuous remission for 2 years.

CONCLUSIONS

The management of our case could help for physicians to make better treatment decisions and provide insights for further exploration in future studies.

The Utility of Fine Needle Aspiration (FNA) Biopsy in the Diagnosis of Mediastinal Lesions

Fine needle aspiration is a minimally invasive, low-morbidity, and cost-efficient technique for the sampling of mediastinal lesions. Additionally, ancillary testing on FNA samples can be used for the refinement of diagnoses and for treatment-related purposes (flow cytometry, cytogenetics, immunohistochemistry, and molecular diagnostics). Mediastinal lesions, however, can show a variety of lineages and morphologic features, giving rise to diagnostic dilemmas. As a result, the differential diagnosis can vary widely and becomes especially challenging due to the smaller sample size on FNA and the variability in component sampling. For appropriate patient management and to determine the correct treatment strategies, accurate pathologic diagnoses are paramount. In this review, we present the cytomorphologic features together with the immunophenotypic findings of mediastinal lesions, with emphasis on the diagnostic challenges and pitfalls in FNA cytology samples, including smears and cell block sections.

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.

Diffuse Large B Cell Lymphoma Arising in Patients with Preexisting Hodgkin Lymphoma

The metachronic onset of diffuse large B-cell lymphoma (DLBCL) after classic Hodgkin lymphoma (cHL) is a rare event affecting patients’ outcomes. However, although several studies have investigated the prognostic role of this event, little is known about a hypothetical common origin of the two different neoplastic cells. Aims: To investigate a possible relationship between DLBCL and cHL, in this retrospective study of 269 patients with newly diagnosed cHL treated at Bari University Hospital (Italy) between 2007 and 2020, we analyzed data from 4 patients (3 male and 1 female) with cHL who subsequently developed DLBCL. Methods: Gene expression profile analysis, assessed by NanoString Lymphoma Subtype Assay, was performed to identify the cell of origin in the DLBCL cases, in addition to Hans’s algorithm. Results: Using Hans’s algorithm, all DLBCL cases showed a germinal center-B-Cell subtype. The gene expression profile evaluated by the NanoString Lymphoma Subtype Assay revealed two cases of the GCB molecular subtype, while the others were unclassified. After first-line chemotherapy, 1 patient achieved complete remission, 3 were non-responders (2 died of lymphoma within 6 months, whereas the other achieved complete remission after autologous and allogeneic stem cell transplantation and is still alive). Conclusions: The origin of the second neoplastic cell in patients with DLBCL with a previous history of cHL remains controversial, although the different immunophenotypic characteristics suggest that it may mainly arise de novo in a subject with a possible individual predisposition to develop lymphoid neoplasms.

Case Report: Phenotypic Switch in High-Grade B-Cell Lymphoma With MYC and BCL6 Rearrangements: A Potential Mechanism of Therapeutic Resistance in Lymphoma?

Lineage switch between myeloid and lymphoid in acute leukemia is well established as a mechanism for leukemic cells to escape chemotherapy. Cross-lineage transformation is also recognized in some solid tumors on targeted therapy, such as adenocarcinomas of the lung and prostate that transforms to neuroendocrine carcinoma on targeted therapy. Now lineage plasticity is increasingly recognized in mature lymphomas, such as small B-cell lymphomas transforming to histiocytic/dendritic cell sarcoma. However, there is no report of aggressive mature B-cell lymphoma switching from one histologic category to another upon targeted therapy. We report here a case of high-grade B-cell lymphoma with MYC and BCL6 rearrangements relapsing as a high-grade plasmablastic neoplasm with MYC and BCL6 rearrangements after R-CHOP and R-EPOCH therapy. Being aware of this rare scenario will help improve our understanding of the underlying mechanisms of therapeutic resistance and progression of lymphoma.

Hemophagocytic lymphohistiocytosis secondary to composite lymphoma: Two case reports

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening disease caused by inherited pathogenic mutations and acquired dysregulations of the immune system. Composite lymphoma is defined as two or more morphologically and immunophenotypically distinct lymphomas that occur in a single patient. Here, we report two cases of HLH secondary to composite lymphoma with mixed lineage features of T- and B-cell marker expression both in the bone marrow and lymph nodes in adult patients.

CASE SUMMARY

Two patients were diagnosed with HLH based on the occurrence of fever, pancytopenia, lymphadenopathy, splenomegaly, hemophagocytosis and hyperferritinemia. Immunohistochemical staining of the axillary lymph node and bone marrow in case 1 showed typical features of combined B-cell and T-cell lymphoma. In addition, a lymph node gene study revealed rearrangement of the T-cell receptor chain and the immunoglobulin gene. Morphology and immunohistochemistry studies of a lymph node biopsy in case 2 showed typical features of T cell lymphoma, but immunophenotyping by flow cytometry analysis of bone marrow aspirate showed B cell lymphoma involvement. The patients were treated with high-dose methylprednisolone combined with etoposide to control aggressive HLH progression. The patients also received immunochemotherapy with the R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) regimen immediately after diagnosis. Both patients presented with highly aggressive lymphoma, and died of severe infection or uncontrolled HLH.

CONCLUSION

We present two rare cases with overwhelming hemophagocytosis along with composite T- and B-cell lymphoma, which posed a diagnostic dilemma. HLH caused by composite lymphoma was characterized by poor clinical outcomes.

How I Diagnose Primary Mediastinal (Thymic) Large B-Cell Lymphoma

OBJECTIVES

Primary mediastinal (thymic) large B-cell lymphoma (PMBL) is an uncommon large B-cell neoplasm recognized by the World Health Organization as a distinct entity on the basis of its unique clinical features, histogenesis, phenotype, and pathogenetic mechanisms. The diagnosis of PMBL can be challenging because of features that may overlap with other (Hodgkin and non-Hodgkin) lymphoma types. This review describes our approach to the diagnosis of PMBL.

METHODS

Two cases are presented to illustrate how we diagnose PMBL and separate PMBL from related histologic and biological mimickers, such as Hodgkin lymphoma and gray zone lymphoma.

RESULTS

A diagnosis of PMBL requires correlation of morphology and immunophenotype with clinical and staging data. Gene expression analysis is not typically performed in clinical labs but has expanded our understanding of the functional pathways underlying this disease and helped identify biomarkers that can be translated to diagnostic practice and possibly to future therapeutic options.

CONCLUSIONS

PMBL and closely related entities can pose diagnostic challenges. It is important to understand the borders between PMBL and other closely related lymphoma types so that patients receive successful primary treatment with curative intent.

Survival among patients with composite and sequential lymphoma between primary mediastinal lymphoma/diffuse large B-cell lymphoma and classical Hodgkin lymphoma: A population-based study

BACKGROUND

Data on composite and sequential lymphoma between primary mediastinal lymphoma/diffuse large B-cell lymphoma (LBCL) and classical Hodgkin lymphoma (cHL) are rare.

METHODS

We identified 25 cases with composite lymphoma (CL), 116 cases developing LBCL as a second primary cancer after cHL (cHL-LBCL), and 74 cases developing cHL as a second primary cancer after LBCL (LBCL-cHL) from the Surveillance, Epidemiology, and End Results (SEER) 18 database. Comparisons of overall survival (OS) and lymphoma cause-specific survival (CSS) between patients with cHL-LBCL or cHL-LBCL and their de novo counterparts were performed.

RESULTS

The 5-year OS of patients with CL was 74.8 %. No significant difference in unadjusted OS and lymphoma CSS were observed between patients with de novo LBCL (LBCL-1 group) and patients with cHL-LBCL. However, the age- and stage-adjusted cHL-LBCL group had inferior OS and lymphoma CSS compared with that in the LBCL-1 group. The unadjusted and adjusted OS and lymphoma CSS in the LBCL-cHL group were significantly worse than patients with de novo cHL.

CONCLUSIONS

CL between LBCL and cHL may have good outcomes. cHL survivors had poorer outcomes after a LBCL diagnosis versus patients with LBCL-1. Significantly poor outcomes were observed in patients with LBCL-cHL compared with patients with de novo cHL.

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.

Mutational landscape of gray zone lymphoma

The mutational landscape of gray zone lymphoma (GZL) has not yet been established, and differences from related entities are largely unknown. Here, we studied coding sequence mutations of 50 Epstein-Barr virus (EBV)-negative GZLs and 20 polymorphic EBV+ diffuse large B-cell lymphoma (DLBCL) not otherwise specified (poly-EBV-L) in comparison with classical Hodgkin lymphoma (cHL), primary mediastinal large B-cell lymphoma (PMBCL), and DLBCL. Exomes of 21 GZL and 7 poly-EBV-L cases, along with paired constitutional DNA, were analyzed as a discovery cohort, followed by targeted sequencing of 217 genes in an extension cohort of 29 GZL and 13 poly-EBV-L cases. GZL cases with thymic niche involvement (anterior mediastinal mass) exhibited a mutation profile closely resembling cHL and PMBCL, with SOCS1 (45%), B2M (45%), TNFAIP3 (35%), GNA13 (35%), LRRN3 (32%), and NFKBIA (29%) being the most recurrently mutated genes. In contrast, GZL cases without thymic niche involvement (n = 18) had a significantly distinct pattern that was enriched in mutations related to apoptosis defects (TP53 [39%], BCL2 [28%], BIRC6 [22%]) and depleted in GNA13, XPO1, or NF-κB signaling pathway mutations (TNFAIP3, NFKBIE, IKBKB, NFKBIA). They also exhibited more BCL2/BCL6 rearrangements compared with thymic GZL. Poly-EBV-L cases presented a distinct mutational profile, including STAT3 mutations and a significantly lower coding mutation load in comparison with EBV- GZL. Our study highlights characteristic mutational patterns in GZL associated with presentation in the thymic niche, suggesting a common cell of origin and disease evolution overlapping with related anterior mediastinal lymphomas.

Incidence Patterns of Sequential or Composite Lymphoma: A Population-Based Cancer Registry Study

The development of multiple histologic types of lymphoma in a single patient has been sporadically reported as sequential or composite lymphoma. However, the incidence pattern of such patients has been rarely evaluated in a large population-based setting. We investigated the incidence of sequential or composite lymphoma based on 11,174 lymphoma records from a population-based cancer registry between 1985-2012 in Nagasaki Prefecture, Japan. We identified 99 lymphoma records were of 49 independent patients other than relapse. The prevalence of the sequential or composite lymphomas in a single patient was 0.44% (95% confidence interval [95% CI], 0.32-0.56%) without sex difference. Among the 49 patients, five (10.2%) were composite/discordant lymphoma. The most frequent "composite lymphoma" was a combination of diffuse large B-cell lymphomas (DLBCL) and adult T-cell leukemia (n = 3). A case of "discordant lymphoma" was a combination of follicular lymphoma on spleen and Waldenström macroglobulinemia on bone marrow. The rest of the patients (n = 44, 89.8% of all composite lymphoma) were "sequential lymphoma" with various combination of lymphoma subtypes on different dates. The major combination of the sequential lymphoma was DLBCL after marginal zone lymphomas (n = 4). In the era of improved survival of lymphoma patients, hematologists should be aware of the development of additional lymphomas.

Hodgkin Reed-Sternberg-Like Cells in Non-Hodgkin Lymphoma

Reed-Sternberg cells (RSCs) are hallmarks of classic Hodgkin lymphoma (cHL). However, cells with a similar morphology and immunophenotype, so-called Reed-Sternberg-like cells (RSLCs), are occasionally seen in both B cell and T cell non-Hodgkin Lymphomas (NHLs). In NHLs, RSLCs are usually present as scattered elements or in small clusters, and the typical background microenviroment of cHL is usually absent. Nevertheless, in NHLs, the phenotype of RSLCs is very similar to typical RSCs, staining positive for CD30 and EBV, and often for B cell lineage markers, and negative for CD45/LCA. Due to different therapeutic approaches and prognostication, it is mandatory to distinguish between cHL and NHLs. Herein, NHL types in which RSLCs can be detected along with clinicopathological correlation are described. Moreover, the main helpful clues in the differential diagnosis with cHL are summarized.