Pathogenesis, diagnosis, and treatment of composite lymphomas

Composite B‑cell lymphoma and extranodal natural killer/T‑cell lymphoma presenting with distinct clone evolution and tumor microenvironment: A report of two cases

Composite lymphoma containing both B-cell lymphoma and extranodal natural killer/T-cell lymphoma (ENKTL) is extremely rare. Clonal evolution and tumor microenvironment (TME) features have not been reported previously. The present study reports one case of the heterochronous occurrence of follicular lymphoma (FL) and ENKTL and one case of the simultaneous occurrence of diffuse large B-cell lymphoma (DLBCL) and ENKTL. The results of targeted DNA sequencing demonstrated the genetic features and dynamic clonal evolution of each component. Notably, in the case of ENKTL secondary from FL, predominant clones harbored in ENKTL were already present at the initial diagnosis of FL and expanded to full clonal prevalence afterward in ENKTL. In the case of synchronous DLBCL and ENKTL, predominant clones in ENKTL were exclusive to those clones dominating in DLBCL. Multiple immunofluorescence and CIBERSORT analyses depicted TME features and showed that CD68+ macrophages were abundant in FL, DLBCL and ENKTL. The present report could broaden our understanding of composite lymphoma.

Composite mantle cell lymphoma with cryptic ins(11;2)(q13;p11.2p11.2)/IGK::CCND1 and lymphoplasmacytic lymphoma with MYD88 L265P mutation

A woman in her 80 s presented with generalized lymphadenopathy, bone marrow (BM) involvement, and leukemic manifestation. Lymph node biopsy revealed typical histopathology of mantle cell lymphoma (MCL) and the CD5+ and immunoglobulin μ+δ+/λ+ immunophenotype, with unmutated IGHV. BM was infiltrated with not only MCL but also another B-cell tumor that was CD5- and μbright+δ+/κ+, being consistent with M proteins in the serum and urine, with mutated IGHV. As the latter lymphoma component carried the MYD88 L265P mutation, this case represented a composite of MCL and lymphoplasmacytic lymphoma. Next-generation sequencing revealed a cryptic insertion of IGK enhancer sequences into the CCND1-major translocation cluster, accounting for CCND1 expression in MCL cells recognized by immunohistochemistry. Composite lymphoma is rare, but a correct diagnosis is required because effective treatments for each component are now available.

Common origin and somatic mutation patterns of composite lymphomas and leukemias

When two lymphomas occur concurrently or sequentially in a patient, it is a major question whether they derive from the same lymphocyte or hematopoietic precursor cell or developed independently. We studied four composite classic Hodgkin lymphomas (HL) and other mature B-cell lymphomas, and two composite mature B- and T-cell neoplasias by whole exome sequencing (WES). Analysis of their IGV genes revealed that three composite B-cell lymphomas originated from common germinal center-experienced B cells. WES identified shared somatic mutations in the lymphomas of these clonally related composite lymphomas, indicating their derivation from a common, pre-malignant precursor. Most mutations were restricted to one or the other of these lymphomas, likely explaining how distinct lymphomas developed from a common ancestral B cell. In the two B-cell/T-cell lymphoma cases, and a composite clonally unrelated HL/chronic lymphocytic leukemia, the lymphoma partners did not share any somatic mutations. In three cases, we identified potentially oncogenic variants also in cells serving as constitutional controls. These variants may have contributed to development of a composite lymphoma/leukemia. We provide additional evidence of frequent clonal relation in composite lymphomas, highlight the multistep transformation process of related lymphomas with a likely pre-malignant intermediate common precursor, and support the importance of constitutional variants in lymphomagenesis.

Treatment and Survival of U.S. Vietnam Veterans With Concurrent Lymphoid Malignancies

INTRODUCTION

In Vietnam veterans, exposure to military toxicants, such as Agent Orange, may be associated with lymphoid malignancies. Toxicant exposure may increase the likelihood of being diagnosed with concurrent lymphoid malignancies, which can occur as composite, discordant, or transformed lymphomas.

MATERIALS AND METHODS

We conducted a large, retrospective case-control study using the national VA Central Cancer Registry to identify cases of concurrent lymphoid malignancies compared to controls of single lymphoid malignancies and the association with Agent Orange.

RESULTS

The occurrence of concurrent lymphoid malignancies was rare (n = 128/32,889, 0.4%). The most common concurrent lymphoid malignancy combinations were chronic lymphocytic leukemia (CLL) and diffuse large B-cell lymphoma, CLL and plasma cell neoplasms, CLL and marginal zone lymphoma, and diffuse large B-cell lymphoma and follicular lymphoma. Agent Orange exposure was not associated with increased odds of being diagnosed with concurrent lymphoid malignancies. Though limited in sample size, patients with concurrent lymphoid malignancies did not appear to have a worse survival compared to patients with single lymphoid malignancies. In our qualitative analysis of treatments for those with concurrent diagnoses, veterans primarily underwent first-line treatment for the more aggressive diagnosis, with few requiring treatments for both diagnoses during their clinical course.

CONCLUSIONS

In this Vietnam Era cohort, Agent Orange exposure did not appear to influence the development of concurrent lymphoid malignancies. Having a diagnosis of concurrent lymphoid malignancies did not appear to significantly affect patient survival. This will inform counseling of veterans with Agent Orange exposure and has implications for future policy development.

Concurrent mucosal and transmural feline intestinal T-cell lymphomas show differing T-cell clonality

The clonality of 14 feline intestinal small and large T-cell lymphomas were examined, which consisted of concurrent mucosal and transmural lymphomas, respectively. Histologically, the small cell lymphomas were localized to the mucosal region and were observed adjacent to large T-cell lymphoma lesions. The large T-cell lymphomas were spread throughout the submucosal region, forming transmural lesions. Both cell types were immunohistochemically stained using anti-cluster of differentiation 3 antibody. For clonality analysis, genomic DNA was extracted from formalin-fixed, paraffin-embedded sections of the mucosal and transmural lesions, separately. Clonality analysis was performed using primer sets targeting T cell receptor beta, T cell receptor delta, and T cell receptor gamma loci. In 12/14 cats, the results of the clonality analysis for T-cells differed between the mucosal and transmural lesions. Despite the fact that the cellular morphologies differed between lesion types, the T-cell clonality was consistent in 1/14 cats, suggesting a common clonal origin. In the remaining case, the clonal relationship between the 2 lesions could not be determined. These results indicate that concurrent lymphomas with small and large T-cells in their mucosal and transmural lesions, respectively, develop via separate pathogenic mechanisms.

Epidemiology characteristics and clinical outcomes of composite Hodgkin lymphoma and diffuse large B-cell lymphoma using machine learning

Composite lymphoma (CL) is rare. We conducted an analysis of 53 329 cases of diffuse large B-cell lymphoma (DLBCL), 17,916 cases of Hodgkin lymphoma (HL), and 869 cases of composite HL and DLBCL from the SEER database diagnosed between 2000 and 2019. Incidence rates showed increasing trends with age for CL and DLBCL, while HL exhibited 2 peak incidence rates: 42.05 (95% CI: 40.88-43.25) per million for the age group 20-24 and 43.20 (95% CI: 41.13-45.35) per million for 75-79. Higher incidence rates were observed in males (CL, 0.68, 95% CI: 0.62-0.74; HL, 29.65, 95% CI: 29.27-30.03; DLBCL, 86.18, 95% CI: 85.51-86.86) compared to females (CL, 0.40, 95% CI: 0.36-0.45; HL, 23.15, 95% CI: 22.83-23.49; DLBCL, 57.56, 95% CI: 57.06-58.06; P < .001). We first identified independent prognostic factors for composite HL and DLBCL, which were used for development of a scoring nomogram. Factors such as primary tumor site, marital status, chemotherapy, and sex predominantly influence short-term survival, while Ann Arbor stage plays a significant role in long-term survival. Furthermore, there were notable differences in demographic characteristics, survival outcomes, and death cause among CL, HL, and DLBCL. This study provides the first comprehensive report of composite HL and DLBCL.

Advances in Hodgkin lymphoma research

Hodgkin lymphoma (HL) has been and still is the most enigmatic lymphoid malignancy in humans. Since the first molecular analysis of isolated Hodgkin and Reed-Sternberg (HRS) tumor cells of classic HL 30 years ago, substantial advances in our understanding of HL have been made. This review describes the cellular origin of HL, summarizes the current knowledge about the genetic lesions in HRS cells, and highlights the role of Epstein-Barr virus (EBV) in HL pathogenesis. Moreover, the pathobiological roles of altered gene expression and deregulated signaling pathways are discussed and key aspects of the HL microenvironment are presented.

Medication Safety in Intravenous Therapy: Compatibility of Etoposide with Frequently Drugs Used in Tumour Critical Care During Simulated Y-Site Administration

Objective

Etoposide is an antineoplastic agent widely used to treat pediatric and adult cancers. Critically ill patients are expected to receive several intravenous pharmaceutical drugs while admitted to hospitals. When compatibility data are available, intravenous drugs may be administered simultaneously through the Y-site. This study aimed to determine the compatibility of etoposide during simulated Y-site administration with 45 continuous-infusion drugs that are commonly administered in tumor critical care units.

Methods

Etoposide was diluted to a concentration of 0.25 mg/mL in 0.9% sodium chloride (NS) and other intravenously tested drugs were reconstituted according to the manufacturer's recommendations to the final clinical desired concentrations. Y-site administration was simulated in vitro by mixing 5 mL etoposide with other diluted intravenous medications under aseptic conditions in a 1:1 ratio. Compatible solutions were withdrawn at certain time intervals (0, 1, 2, 4 hours) after mixing and tested visually, using a Tyndall beam, pH, turbidity, insoluble particles, and UV absorption as measures of compatibility.

Results

Etoposide was compatible with 38 (84%) of the 45 drugs tested within four hours. Glutathione and human granulocyte colony-stimulating factor immediately showed incompatibility with etoposide. Within 1 h, four medications (cefuroxime sodium, ilaprazole sodium, mycophenolate, and xuebijing) were incompatible. Within 4 h, one medications (ceftazidime) were also found to be incompatible with etoposide under observation.

Conclusion

Seven of the 45 common medications in tumor critical care tested with etoposide were incompatible within 4 h. If co administration is inevitable and the drug is infused through a port catheter, a larger volume of saline (NS) or dextrose 5% in water (D5W) should be used to flush the port catheter before and after the etoposide infusion to clean the lumen of the port catheter.

Composite Lymphoma after Treatment with Infliximab for Sarcoidosis and Ankylosing Spondylitis

Lymphoid proliferations and lymphomas associated with immune deficiency and dysregulation (LP/L-IDD) are rare entities associated with the use of immunosuppressive drugs (ISD) for autoimmune conditions. Composite lymphomas, featuring both B-cell and T-cell lymphomas, are infrequent, and their occurrence as LP/L-IDD is rare. We herein report the case of a 70-year-old man with right pleural effusion and lymphadenopathy, who was treated with infliximab for sarcoidosis and ankylosing spondylitis. A biopsy revealed a composite lymphoma of DLBCL and PTCL-NOS. CHOP chemotherapy led to significant remission. This case report emphasizes the need to consider lymphoma in patients with autoimmune diseases such as sarcoidosis and ankylosing spondylitis, especially those treated with ISDs.

From the archives of MD Anderson Cancer Center: Composite mantle cell lymphoma and lymphoplasmacytic lymphoma involving bone marrow at presentation

Composite lymphoma, defined as two or more distinct well-defined entities involving the same anatomic site, is rare. Here we report a 79-year-old woman with composite mantle cell lymphoma (MCL) and lymphoplasmacytic lymphoma (LPL) involving bone marrow at the time of initial diagnosis. The patient presented with splenomegaly and lymphadenopathy and laboratory studies showed an elevated serum IgM level and IgM kappa paraprotein. Bone marrow evaluation showed concurrent involvement by MCL and LPL, supported by immunophenotypic studies that revealed two distinct aberrant B-cell populations. Next-generation sequencing analysis identified concurrent MYD88 and CXCR4 mutations and fluorescence in-situ hybridization showed CCND1 translocation, supporting the diagnosis of concomitant MCL and LPL. In conclusion, composite lymphoma can present in the bone marrow. The use of ancillary studies was essential in reaching the diagnosis in this case, as the results excluded the possibility of MCL lymphoma with plasmacytic differentiation, as well as other CD5- and CD10-negative small B-cell lymphomas.

Nodal T follicular helper cell lymphoma with aberrant CD20 expression and monoclonal TCR, IG rearrangements secondary to Classical Hodgkin Lymphoma: a case report

Classical Hodgkin Lymphoma (CHL) is a rare malignant neoplasm of the lymphatic system. While CHL typically responds well to conventional treatments, some cases may experience relapse to other subtypes, with the development of secondary peripheral T-cell lymphoma (PTCL) being relatively uncommon. Herein, we report a rare case of nodal T follicular helper cell lymphomas,nos (nTFHL-NOS) secondary to CHL, accompanied by aberrant CD20 expression and clonal rearrangements of T-cell receptor (TCR) and immunoglobulin (IG). A 74-year-old male, was diagnosed with CHL, leaning toward the mixed cell type, 6 years ago. He received six cycles of the Adriamycin, Bleomycin, Vinblastine, Dacarbazine (ABVD) regimen, achieving complete clinical remission. The patient was admitted to our hospital due to the appearance of multiple skin nodules 66 months later. Histopathological analysis revealed nTFHL-NOS, with aberrant CD20 expression and clonal rearrangements of TCR and IG. The patient underwent two cycles of chemotherapy with brentuximab vedotin and the Gemcitabine-Oxaliplatin (G-mox) regimen, resulting in a reduction of the skin lesions to 2 cm × 1 cm. We discuss this rare case and review related literature.

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.

Double trouble: insights from a rare case of extranodal composite lymphoma in an elderly man, with comprehensive literature review

Composite lymphoma (CL) is a rare cancer characterized by the concurrent occurrence of more than one type of lymphoma within the same organ or tissue in an individual. Its occurrence at extranodal sites is exceptional, with only a few cases documented in the literature. A 62-year-old gentleman presented with dystonia, dysphagia, and irregular enlargement of the right tonsil for the last three months. Based on a clinical suspicion of tonsillar malignancy, tonsillectomy was done. The histopathologic examination revealed effacement of the architecture by large irregular lymphoid nodules with interfollicular expansion. The nodules showed sheets of small atypical lymphoid cells, while the interfollicular areas showed large atypical lymphoid cells with scattered typical binucleate Reed-Sternberg cells. Immunohistochemistry confirmed mantle cell lymphoma (MCL) in the nodules and classical HL (cHL) in the interfollicular areas. Based on these features, a diagnosis of composite MCL with cHL was rendered. He was treated with bendamustine and rituximab chemotherapy and remained in complete remission for five years when he presented with significant right-sided neck swelling. Percutaneous fine needle aspiration and subsequent flow cytometry confirmed a relapse of the MCL component of the CL. The index report documents an exceptional case of CL, comprising MCL and cHL, presenting at an uncommon extranodal site. In addition, it also emphasizes the importance of adequate sampling and the simultaneous use of immunochemistry and/or flow cytometry to confirm the presence of more than a single type of lymphoma, which may be easily overlooked on microscopy alone.

Composite Burkitt Lymphoma and Classical Hodgkin Lymphoma in an Human Immunodeficiency Virus (HIV)-Positive Patient

Lymphoma, a term encompassing tumor masses in the lymph nodes, is often classified into Hodgkin and non-Hodgkin lymphomas, each with distinct subtypes. We present the unique case of an HIV-positive patient diagnosed with Burkitt lymphoma and classical Hodgkin lymphoma simultaneously as a composite lymphoma. Over the course of five years, a variety of dose-adjusted chemotherapy regimens were used that ultimately proved highly effective. The successful management of this rare case reinforces the significance of considering unexpected combinations of neoplastic processes during diagnosis and treatment planning.

Composite diffuse large B-cell lymphoma and peripheral T-cell lymphoma: a case report with two-year follow-up and literature review

Composite lymphoma is an uncommon type of lymphoid malignancy, and those consisting of concurrent diffuse large B-cell lymphoma (DLBCL) and peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) in the same organ are rare. Here, we report a case of a 75-year-old male patient admitted to our emergency department with intestinal obstruction presenting with abdominal pain and vomiting. He underwent partial resection of the small intestine under general anesthesia, and subsequent histopathology confirmed the mass to be composite DLBCL and PTCL-NOS. The patient received chemotherapy with a rituximab-based regimen and achieved complete remission (CR). However, the recurrent disease presented with obstruction again ten months after treatment. He refused a second surgery, but salvage treatment was not effective. The patient survived for 20 months after diagnosis. In addition, we did a literature review to understand the clinical features, pathology, treatment, and prognosis of this type of composite lymphoma.

An Atypical relapsing follicular lymphoma to composite Hodgkin's lymphoma

Composite lymphoma is defined as two or more lymphomas with distinct morphological and immunophenotypical characteristics synchronously diagnosed at the same anatomical site. Composite lymphoma is rare, and the most common combination is follicular lymphoma (FL) associated with diffuse large B cell lymphoma, followed by FL associated with classic Hodgkin's lymphoma (HL). Histologically, composite lymphomas display a mixed pattern or distinct zonal distribution of each lymphoma component. Composite lymphoma poses a diagnostic challenge, especially when two lymphoma components are mixed in the same lymph node. Here, we report a case of composite HL and FL 11 years after initial and repeat biopsies consistent with FL in a man in his 70s emphasising the importance of repeat biopsy in lymphoma diagnosis.

Biclonal Low-Grade B Cell Lymphoma as Detected by Multiparametric Flow Cytometry in Blood and Marrow

Biclonal B cell lymphomas (BCL) of two different low-grade components are rare. Multiparametric flow cytometry (MFC) is an integral tool in lymphoma diagnosis and very efficient in picking up BCL cases, especially when the associated second component is small. We studied the incidence of BCL in the routine blood and marrow samples sent for immunophenotyping by MFC. A total of 376 cases were analyzed retrospectively. We studied their clinical, immunophenotypic, molecular, and cytogenetic findings with literature review. We found five cases of BCL with two different clonal low-grade B cell components at an incidence of 1.3%. All cases were males with a median age of 68 years. The chronic lymphocytic leukemia (CLL) clone was present in all 5 cases. The other associated component in cases 1 to 5 were lymphoplasmacytic lymphoma, follicular lymphoma, splenic marginal zone lymphoma, hairy cell leukemia, and monoclonal B cell population of non-CLL type respectively. Diagnosing BCL may be challenging and may also go undiagnosed when the second component is petite and overshadowed by the more significant component. It may be critical if the small, unnoticed lymphoma component is of a more aggressive type.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12288-022-01625-y.

Composite Lymphoma's Ability to Adapt and Change Through Plasticity: A Case Report and Literature Review

Composite/synchronous lymphoma is an uncommon condition that presents a challenge in histopathological diagnosis due to the simultaneous appearance of two or more lymphomas, including instances where they are intermixed within the same location. Performing a core needle tissue biopsy adds a challenge for pathologists when trying to diagnose a condition that requires excisional tissue for a thorough evaluation. This report highlights a distinctive instance of composite lymphoma in which classical Hodgkin lymphoma (cHL) is combined with diffuse large B-cell lymphoma (DLBCL). All pertinent information including clinical, histopathological, and immunohistochemical data for each of these composite lymphomas is provided. In addition, we conducted a literature review of the published data. The findings from these data further support the theory of a shared clonal origin and transdifferentiation occurrence in the process of lymphoma development.

Composite B-cell and T-cell lymphomas: clinical, pathological, and molecular features of three cases and literature review

Composite lymphoma (CL) involving B-cell lymphoma and T-cell lymphoma is extremely rare. Herein, we report three such cases using immunohistochemistry, flow cytometry, and the next-generation sequencing (NGS) to identify the pathological and molecular characteristics of CL. In the first case, the patient was admitted to hospital for generalized pruritic maculopapular rash over the whole body. An excisional biopsy of the skin lesions showed T-cell lymphoma. At the same time, the staging bone marrow (BM) biopsy revealed a diffuse large B-cell lymphoma (DLBCL). After R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) therapies, the patient produced a good response with substantial dissipation of the rashes and relief of skin. The other two patients were admitted to hospital due to lymphadenopathy and were diagnosed with DLBCL and follicular lymphoma (FL) after core needle biopsy of lymph nodes, BM biopsy, BM aspiration, and flow cytometry. Following R-CHOP and R-COP (rituximab, cyclophosphamide, vincristine, and prednisone) therapies, they achieved complete remission unconfirmed (CRu) and complete remission (CR). However, one or two years later, they suffered a relapse of lymphadenopathy. The shocking fact was that re-biopsy of lymphadenopathy revealed peripheral T-cell lymphoma (PTCL) and angioimmunoblastic T-cell lymphoma (AITL). NGS findings identified DNA methyltransferase 3a (DNMT3a), isocitrate dehydrogenase 2 (IDH2), Ras homolog gene family, member A (RHOA), splicing factor 3B subunit 1 (SF3B1), and tumor protein p53 (TP53) mutations. After immunochemotherapy, these patients achieved CRu and CR again. Nevertheless, they suffered a second relapse of T-cell lymphoma. Finally, they died due to progression of disease. We found that the occurrence of CL is associated with Epstein-Barr virus infection and DNMT3a, IDH2, and TP53 mutations, and the prognosis of the disease is closely related to the T-cell lymphoma components.

Case report: Composite mantle cell lymphoma and classical Hodgkin lymphoma

Composite mantle cell lymphoma and classical Hodgkin lymphoma is very rare and the actual origin of it is still unclear. Here we reported a new case of composite mantle cell lymphoma and classical Hodgkin lymphoma and analyzed its molecular changes. Eight mutations were identified in its Hodgkin component through next-generation sequencing. In addition, we reviewed the published cases of composite mantle cell lymphoma and classical Hodgkin lymphoma and summarized the molecular changes of reported cases as well as the current case to explore the possible pathway of histogenesis.

Concurrent Presentation of Mycosis Fungoides and Primary Cutaneous Marginal Zone LPD: Clinicopathological Study of 4 Cases and Literature Review

BACKGROUND

Mycosis fungoides is rarely associated to B-cell malignancies, and the few reported cases are mainly internal lymphomas involving secondarily the skin (ie, chronic lymphocytic leukemia).

OBJECTIVES

The aim of our study is to describe the clinical and histopathological features of 4 patients presenting with 2 concurrent primary cutaneous lymphomas and review the pertinent literature.

METHODS

We identified 4 cases of concurrent primary cutaneous lymphomas in our institutions. An extracutaneous lymphoma was ruled out on the basis of a complete work out. We performed a PubMed search to identify reported cases of primary cutaneous composite or concurrent lymphomas.

RESULTS

Eleven cases of primary cutaneous concurrent lymphomas have been described in the literature. Counting all together (our cases and the cases previously described in the literature), mycosis fungoides was the most frequent primary cutaneous T-cell lymphoma (TCL) (13/15), followed by 1 case of peripheral TCL-NOS and 1 case of subcutaneous panniculitis-like TCL. Regarding the associated primary cutaneous B-cell lymphomas, 8/15 cases consisted of low-grade B-cell lymphomas [that is, 5 marginal zone lymphoma (in the most recent classification reclassified as marginal zone lymphoproliferative disorder, MZLD, 2 follicular-center B-cell lymphoma (primary cutaneous follicle-center lymphoma) and 1 low-grade NOS B-cell lymphoma]; 4/15 were associated to Epstein-Barr virus; 1 case consisted of a methotrexate-associated lymphoproliferative disease, and 2 cases consisted of primary cutaneous diffuse large B-cell lymphoma-leg type.

CONCLUSIONS

Primary cutaneous concurrent lymphomas are exceptional. Clinicopathological correlation and a complete workout to reach the correct diagnosis may guide the appropriate treatment in each case.

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.

Investigation of epidemiological characteristics and development of a nomogram to predict survival in primary ocular adnexal lymphoma

BACKGROUND

Studies on the epidemiology and prognosis of primary ocular adnexal lymphoma (POAL) are scarce for its low occurrence. The goal of our research was to assess the epidemiologic characteristics, prognostic variables and survival of POAL patients.

METHODS

The Surveillance, Epidemiology and End Results (SEER) database was used to collect data on patients identified with POAL from 1975 to 2011 and the incidence rate of POAL from 1975 to 2017. To discover independent predictive markers for overall survival (OS) and disease-specific survival (DSS), multivariable Cox regression analysis was utilised. The independent prognostic factors found by multivariate Cox regression analysis were used to generate a nomogram.

RESULTS

A total of 2839 patients were diagnosed with POAL, with an average age of 64.1 years. The total incidence of POAL was 2.51/1000000 (according to the overall adjustment of the 2000 American standard) from 1975 to 2017, and the annual percentage change (APC) was 2.47 (95% confidence interval 1.64-3.32, p < 0.05), showing a sharp upward trend. After multivariate Cox regression analysis, age, gender, year of diagnosis, marital status, primary site, laterality, pathological type and treatment strategy were evaluated as independent prognostic factors of OS or DSS (p < 0.05). A nomogram was constructed to forecast the DSS of 1, 3, 5 and 10 years. The concordance index (C-index) and the calibration plots demonstrated the robustness and accuracy of the nomogram.

CONCLUSIONS

Although POAL is sporadic, the incidence has generally increased in the past 36 years. In recent years, survival rates have risen, and radiotherapy can render better OS and DSS. The nomogram specially made for POAL is robust and precise in predicting the DSS of 1, 3, 5 and 10 years.

Molecular Diagnostic Review of Diffuse Large B-Cell Lymphoma and Its Tumor Microenvironment

Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma. It is a clinically and morphologically heterogeneous entity that has continued to resist complete subtyping. Molecular subtyping efforts emerged in earnest with the advent of gene expression profiling (GEP). This molecular subtyping approach has continued to evolve simultaneously with others including immunohistochemistry and more modern genomic approaches. Recently, the veritable explosion of genomic data availability and evolving computational methodologies have provided additional avenues, by which further understanding and subclassification of DBLCLs is possible. The goal of this review is to provide a historical overview of the major classification timepoints in the molecular subtyping of DLBCL, from gene expression profiling to present day understanding.

[Composite lymphoma: Case report of a coexisting follicular and mantle cell lymphoma in situ in a cervical node]

Composite lymphoma represents 1-4% of lymphomas. Only 8 case reports concerned coexisting follicular lymphoma and mantle cell lymphoma. Here, we report the case of an 81 years old man who has been diagnosed with a composite follicular and in situ mantle cell lymphoma. The use of a large panel of immunohistochemical stains associated with the flow cytometry results have allowed us to make this particular diagnosis. We highlight here a common clonal origin of the composite lymphoma's two entities, as described in previous publications.

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.

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.

Composite Lymphoma Containing Mantle Cell and Peripheral T-cell Lymphoma, Not Otherwise Specified: A Report of 2 Cases Treated With Up-front Autologous Stem Cell Transplantation

We report 2 cases of composite lymphoma comprising mantle cell lymphoma and peripheral T-cell lymphoma, not otherwise specified, a rare association that has only been reported twice in the literature. In case 1, a 64-year-old woman presented with massive splenomegaly and lymphadenopathy. Immunohistochemical studies of the lymph node biopsy suggested the presence of 2 lymphomas, a predominant component of a peripheral T-cell lymphoma, not otherwise specified and an in situ mantle cell neoplasia. These suspicions were confirmed with polymerase chain reaction and fluorescence in situ hybridization studies. In case 2, a 45-year-old man presented with an enlarged right tonsil. Contrary to case 1, the biopsy suggested a predominant infiltration of a classical mantle cell lymphoma and an atypical proliferation of T cells. Biclonality was also confirmed with fluorescence in situ hybridization and molecular techniques. Both cases were treated with an up-front autologous stem cell transplantation after achieving first complete remission, and they remained free of disease for a long period of time.

Angioimmunoblastic T-Cell Lymphoma and Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma: A Novel Form of Composite Lymphoma Potentially Mimicking Richter Syndrome

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is an indolent small B-cell neoplasm that may transform into a clinically aggressive disease, namely Richter syndrome, usually as diffuse large B-cell lymphoma. Besides, CLL/SLL encompasses an increased risk of developing other secondary cancers, including a variety of T-cell lymphomas, often of the anaplastic large-cell type or with a cytotoxic phenotype. Here, we report a small series of patients with composite lymphomas consisting of CLL/SLL and angioimmunoblastic T-cell lymphoma (AITL), a hitherto unrecognized association. The 3 patients (1 male/2 females, 68 to 83 y) presented with high-grade-type symptoms. One patient was clinically suspicious for Richter syndrome, in the others CLL/SLL and AITL were concomitant de novo diagnoses. CLL/SLL and AITL were admixed in the same lymph nodes (3/3 cases) and in the bone marrow (1/2 cases). In all cases, the AITL comprised prominent clear cells with a strong T follicular helper immunophenotype and similar mutations consisting of TET2 or DNMT3A alterations, IDH2 R172K/M, and RHOA G17V. The 3 patients received chemotherapy. One died of early AITL relapse. The other 2 remained in complete remission of AITL, 1 died with recurrent CLL, and 1 of acute myeloid leukemia. These observations expand the spectrum of T-cell lymphoma entities that occur in association with CLL/SLL, adding AITL to the rare variants of aggressive neoplasms manifesting as Richter syndrome. Given that disturbances of T-cell homeostasis in CLL/SLL affect not only cytotoxic but also helper T-cell subsets, these may contribute to the emergence of neoplasms of T follicular helper derivation.

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.

Composite Epstein-Barr Virus-associated T-lymphoblastic and Peripheral T-cell Lymphomas: A Clonal Study

A 30-year-old woman was diagnosed with T-lymphoblastic lymphoma (T-LBL) that harbored a clonal Epstein-Barr virus (EBV) genome. At relapse, axillary lymph node adenopathy, which was diagnosed as peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), was detected. Southern blot analyses of the T-cell receptor and EBV genome revealed that the T-LBL and PTCL-NOS were clonally identical. We previously showed that CD21 acted as an entry molecule that allowed EBV into the patient's T-LBL cells. Interestingly, the PTCL-NOS cells lacked CD21 expression. Our case suggests that EBV might infect immature CD21-positive T-cells, and CD21-negative PTCL-NOS might subsequently arise through phenotypic changes.

Coexistence of Hodgkin and Non-Hodgkin Lymphoma; Composite Lymphoma [CL] in a Patient Presenting with Waxing and Waning Lymphadenopathy

BACKGROUND

The coexistence of two or more types of lymphoma within the same organ at the same time of diagnosis is defined as composite lymphoma, a rare disease that has recently been identified in the literature. Pointedly, the concurrence may be Hodgkin lymphoma with a Non-Hodgkin lymphoma [NHL], either B or T cells, or two different entities of NHLs. Furthermore, this condition has been described concurrently or sequentially. In order for the diagnosis to be established, two or more distinct clones should be proven by morphological and laboratory tests.

CASE PRESENTATION

Herein, we cite a seventy-three-year old female patient with low-grade fever, waxing and waning cervical lymphadenopathy, whose biopsy of an axillary lymph node demonstrated the rare coexistence of Hodgkin and NHL, known as composite lymphoma.

CONCLUSION

Composite lymphomas pose a particular diagnostic challenge, and currently, there are no agreed standards for treatment.

Pathological and molecular analysis of a composite lymphoma of mantle cell lymphoma and Epstein-Barr virus-positive follicular lymphoma

Composite lymphoma (CL) is a very rare clinical entity defined by the presence of two or more different subtypes of lymphoma in the same lymph node. We report a case of CL in a 78-year-old male presenting with leukocytosis and swelling of multiple lymph nodes. A left axillary node biopsy showed atypical lymphocytes in both the interfollicular and follicular areas. Immunohistochemistry revealed that mantle cell lymphoma (MCL) was mainly present in the interfollicular area and follicular lymphoma (FL) was present in the follicular area. Polymerase chain reaction analysis of immunoglobulin heavy chain gene rearrangements confirmed that they were clonally related neoplasms. However, Epstein-Barr virus (EBV) DNA was detected in only FL cells, suggesting that MCL and FL had split into two clones in the early steps of pathogenesis. This is the first reported case of CL with EBV-negative B-cell non-Hodgkin lymphoma (NHL) and EBV-positive B-cell NHL with a clonal relationship. We discuss the developmental processes of these two lymphomas.

Clonal dynamics in a composite chronic lymphocytic leukemia and hairy cell leukemia-variant

Composite lymphoma is the rare simultaneous manifestation of two distinct lymphomas. Chronic lymphocytic leukemia (CLL) has a propensity for occurring in composite lymphomas, a phenomenon that remains to be elucidated. We applied cytogenetics, droplet digital polymerase chain reaction, and massively parallel sequencing to analyze longitudinally a patient with CLL, who 3 years later showed transformation to a hairy cell leukemia-variant (HCL-V). Outgrowth of the IGHV4-34-positive HCL-V clone at the expense of the initially dominant CLL clone with trisomy 12 and MED12 mutation started before CLL-guided treatment and was accompanied by a TP53 mutation, which was already detectable at diagnosis of CLL. Furthermore, deep sequencing of IGH showed a composite lymphoma with presence of both disease components at all analyzed timepoints (down to a minor clone: major clone ratio of ~1:1000). Overall, our analyses showed a disease course that resembled clonal dynamics reported for malignancies with intratumoral heterogeneity and illustrate the utility of deep sequencing of IGH to detect distinct clonal populations at diagnosis, monitor clonal response to therapy, and possibly improve clinical outcomes.

Clonally Related Plasmablastic Lymphoma Simultaneously Occurring with Diffuse Large B-Cell Lymphoma

Plasmablastic lymphoma (PBL) is a rare aggressive lymphoma. Although it was first described in HIV- (human immunodeficiency virus-) infected patients, PBL has been diagnosed in patients with other immunodeficiencies as well as in immunocompetent patients. PBL immunohistochemically expresses plasmacytic markers and lacks pan B-cell markers. The cells of origin of PBL are considered to be plasmablasts. MYC gene rearrangement and MYC overexpression are frequently found in PBL, but the pathogenesis of PBL is yet to be elucidated. Here, we report a case of composite lymphoma of PBL and diffuse large B-cell lymphoma (DLBCL); that is, PBL in the urinary bladder and DLBCL in the nasal cavity occurred simultaneously. We extracted DNA from the two lymphomas for polymerase chain reaction and sequenced the amplified immunoglobulin heavy variable genes and the complementarity-determining region- (CDR-) 3. The sequence of the CDR3 region of both tumors matched. MYC rearrangement was found in the bladder tumor but not in the nasal tumor. The patient was treated with R-CHOP (rituximab, cyclophosphamide, vincristine, doxorubicin, and prednisone), and durable remission had been obtained. The results of the DNA analysis indicated that both PBL and DLBCL emerged from common postgerminal B cells. This case may help to elucidate the pathogenesis of PBL.

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.

Simultaneous Presentation of Leukemic Non-Nodal Mantle Cell Lymphoma and Gamma-Delta T-Large Granular Lymphocytic Leukemia in a Patient with Rheumatoid Arthritis

The peculiar features of T-cell large granular lymphocytic leukemia (T-LGLL) are its association with autoimmune disorders (particularly with rheumatoid arthritis (RA)) and a broad spectrum of B-cell lymphoproliferative disorders. However, association of T-LGLL with mantle cell lymphoma (MCL) is extremely rare. Here, we describe a case of an 80-year-old man admitted with suspected Felty's syndrome. The blood count showed white blood cells at 2.2×109/L, with 3% neutrophils, 88% lymphocytes, and at 0.66×109/L LGLs. The spleen had been removed 43 months prior to the admission due to suspected B-cell splenic lymphoma. Re-examination of the spleen revealed cyclin D1+ and SOX11- lymphocytes in the inner part of the unexpanded mantle zones of the white pulp follicles, thus displaying a so-called in situ histologic pattern of MCL, and in small clusters in the red pulp. The splenic cords were moderately expanded by lymphocytes expressing CD3, TIA1, and granzyme B but not CD4 and CD8. Monoclonal rearrangements of the immunoglobulin heavy chain gene and the T-cell receptor (TCR) gamma and delta chain genes, polyclonal rearrangements of the TCR beta chain gene, mutation of the signal transducer and activator of transctiption 3  gene (c.1940A>T; p.N647I), and t(11;14)(q13;q32) translocation were identified in the spleen sample. Flow cytometry of bone marrow revealed a population of TCR γδ+, CD3+, CD4-, CD5-, CD7+, CD8-, CD16-, CD56-, and CD57- lymphocytes. Fragment analysis demonstrated identical TCR gene clonal rearrangement patterns in the spleen and bone marrow samples. In this study, we describe the first case of simultaneous presentation of γδ T-LGLL and leukemic non-nodal MCL (L-NN-MCL) in a patient with RA and present morphological findings of L-NN-MCL in the spleen.

Co-occurrence of EBV-positive classic Hodgkin lymphoma and B-cell lymphomas of different clonal origins: A case report and literature review

Although cases with metachronous or synchronous co-occurrence of classic Hodgkin lymphoma (CHL) and B-cell non-Hodgkin lymphoma (B-NHL) have been reported, few reports have analyzed the clonal relationship between both lesions in detail, especially in Epstein-Barr virus (EBV)-positive settings. Here, we report a case of a 38-year-old male with CHL, followed by the recurrence of EBV-positive mucocutaneous ulcers of the large intestine and EBV-positive diffuse large B-cell lymphoma in the liver. Surprisingly, polymerase chain reaction analysis for immunoglobulin heavy chain gene rearrangement revealed that all lesions were clonally distinct. We further reviewed the literature on synchronous and metachronous co-occurrence of CHL and B-NHL in EBV-positive settings. In contrast to EBV-negative settings, all evaluable cases showed clonally distinct multiple lesions. These findings suggest that histologically and clonally distinct B-cells could simultaneously proliferate in EBV-associated settings, providing a new insight into the pathogenesis of EBV-associated lymphoproliferative disorders.

Composite follicular lymphoma and "early" (in situ and mantle zone growth pattern) mantle cell neoplasia: A rare entity with peculiar cytogenetic and clinical features

Composite follicular lymphoma (FL) and mantle cell lymphoma (MCL) is rare and not fully characterized from a genetic and clinicopathological point of view. We report a composite lymphoma (CL) in which a G1-2 FL was associated with an in situ mantle cell neoplasia (ISMCN) and a mantle zone growth pattern (MZGP) MCL, followed-up for six years after the first diagnosis, until the exitus of the patient. We performed a comprehensive immunohistochemical study and a detailed cytogenetic analysis, including conventional karyotyping, SKY FISH, FISH on metaphases and interphasic separated nuclei, and FISH on histological sections. The study was completed by the review of the 13 published composite FL and MCL. Our results show that this entity generally behaves like an indolent lymphoma, with the outcome of patients driven by the progression of the FL component. The MCL component generally does not evolve in an aggressive disease. Indeed, half of the cases present exclusively ISMCN. In our case, mantle cell neoplasia at diagnosis was represented by ISMCN and MZGP MCL and it was characterized by a simple karyotype, with t(11;14) as the sole cytogenetic abnormality. This cytogenetic aspect well correlates with the indolent behavior of the mantle cell component. Conversely, the complex karyotype of the FL component was associated with disseminated disease that influenced patient's outcome. Finally, we suggest that not only ISMCN, but also isolated MZGP MCL, may be considered as lesions with low potential of transformation in an aggressive MCL.

Complexities in the diagnosis of large B-cell lymphomas, classic Hodgkin lymphomas and overlapping peripheral T-cell lymphomas simplified: An evidence-based guide

The diagnosis of a large B-cell lymphoma and classic Hodgkin lymphoma (CHL) is often straightforward. However, in select circumstances, these simple diagnoses can be quite complex. In part, diagnostic difficulty may be due to uncertainty in the evaluation of morphologic and immunophenotypic features along a biologic continuum, or alternatively arise from uncertainty in predicting the behavior and outcomes of patients. Here, we systematically discuss and review areas of diagnostic difficulty in the diagnosis of large B-cell lymphomas (LBCL), classic Hodgkin lymphomas (CHL) and peripheral T-cell lymphomas (PTCL). We provide careful data-driven analyses and evidence-based approaches to help guide pathologists and clinicians. We discuss: 1) marginal zone lymphomas with increased large cells versus diffuse large B-cell lymphoma (DLBCL), 2) chronic lymphocytic leukemia with expanded proliferation centers versus diffuse large B-cell lymphoma (DLBCL), 3) chronic lymphocytic leukemia with Hodgkin/Reed-Sternberg-like cells versus CHL arising from chronic lymphocytic leukemia, 4) complex cases of follicular lymphoma versus DLBCL, 5) PTCL with large B-cell proliferations versus PTCL with LBCL, 6) PTCL with Hodgkin/Reed-Sternberg-like cells versus CHL, and finally 7) blastoid/pleomorphic mantle cell lymphoma versus DLBCL. Our evidence and data driven approach may serve as a useful diagnostic guide.

A Probabilistic Classification Tool for Genetic Subtypes of Diffuse Large B Cell Lymphoma with Therapeutic Implications

The development of precision medicine approaches for diffuse large B cell lymphoma (DLBCL) is confounded by its pronounced genetic, phenotypic, and clinical heterogeneity. Recent multiplatform genomic studies revealed the existence of genetic subtypes of DLBCL using clustering methodologies. Here, we describe an algorithm that determines the probability that a patient's lymphoma belongs to one of seven genetic subtypes based on its genetic features. This classification reveals genetic similarities between these DLBCL subtypes and various indolent and extranodal lymphoma types, suggesting a shared pathogenesis. These genetic subtypes also have distinct gene expression profiles, immune microenvironments, and outcomes following immunochemotherapy. Functional analysis of genetic subtype models highlights distinct vulnerabilities to targeted therapy, supporting the use of this classification in precision medicine trials.

The broad landscape of follicular lymphoma: Part II

Follicular lymphoma is a neoplasm derived from follicle center B cells, typically both centrocytes and centroblasts, in variable proportions according to the lymphoma grading. The pattern of growth may be entirely follicular, follicular and diffuse and rarely completely diffuse. It represents the second most common non-Hodgkin lymphoma, after diffuse large B-cell lymphoma and it is the most common low-grade mature B-cell lymphoma in Western countries. In the majority of cases, follicular lymphoma is a nodal tumor, occurring in adults and is frequently associated with the translocation t(14;18)(q32;q21)/IGH-BCL2. However, in recent years the spectrum of follicular lymphoma has expanded and small subsets of follicular lymphoma, which differ from common follicular lymphoma, have been identified and included in the current 2017 WHO classification. The aim of our review is to describe the broad spectrum of follicular lymphoma, pointing out that the identification of distinct clinicopathological variants of follicular lymphoma is relevant for the patient outcomes and treatment.