Whole-genome analysis and HLA genotyping of enteropathy-type T-cell lymphoma reveals 2 distinct lymphoma subtypes

Pathogenesis of Enteropathy-Associated T Cell Lymphoma

PURPOSE OF REVIEW

To provide an update on the pathogenesis of enteropathy-associated T cell lymphoma (EATL) and its relationship with refractory celiac disease (RCD), in light of current knowledge of immune, genetic, and environmental factors that promote neoplastic transformation of intraepithelial lymphocytes (IELs).

RECENT FINDINGS

EATL frequently evolves from RCD type II (RCD II) but can occur "de novo" in individuals with celiac disease. Recurrent activating mutations in members of the JAK/STAT pathway have been recently described in EATL and RCD II, which suggests deregulation of cytokine signaling to be an early event in lymphomagenesis. Intraepithelial T cells are presumed to be the cell of origin of EATL (and RCD II). Recent in vitro molecular and phenotypic analyses and in vivo murine studies, however, suggest an origin of RCD II from innate IELs (NK/T cell precursors), which could also be the cell of origin of RCD II-derived EATL. The immune microenvironment of the small intestinal mucosa in celiac disease fosters the development of EATL, often in a multistep pathway.

Immunohistochemical Profiling of Canine Intestinal T-Cell Lymphomas

Human enteropathy-associated T-cell lymphoma (EATL) is classified into 2 distinct subgroups based on their phenotypes (type I and type II). Canine intestinal T-cell lymphoma can be morphologically classified into large and small cell lymphomas (LCL and SCL, respectively). Their association with human EATL or immunohistochemical and biological features has not been well characterized. In this study, the immunohistochemical profiles of 17 cases of LCL and 33 cases of SCL were evaluated with markers used for human EATL classification. Morphologically, LCL was characterized by sheet-like proliferation of large to moderately sized neoplastic lymphocytes, with scant clear cytoplasm and pleomorphic, irregularly shaped nuclei containing distinctive nucleoli and scattered chromatin. In contrast, SCL was characterized by the proliferation of monomorphic small neoplastic lymphocytes, accompanied by infiltration of nonneoplastic plasma cells. Interestingly, 8 cases demonstrated mixed LCL and SCL morphologies. Granular cytoplasmic expression of granzyme B was observed in most LCL and SCL cases. Membranous expression of CD56 was demonstrated in only 2 of 17 LCL and 0 of 33 SCL cases. Coexpression of CD20 by neoplastic T cells was observed in more SCL cases (16/33; 48%) than LCL cases (1/17; 6%). The CD56-positive cells in 2 cases were negative for CD20. Although canine LCL shares common features with human EATL type I, canine SCL cells and human EATL type II differ in their immunophenotype. Canine intestinal T-cell lymphoma had a homogeneous immunophenotype regardless of cell morphology. The findings of this study may indicate large cell transformation of SCL rather than 2 distinct entities.

A Single-Tube, EuroClonality-Inspired, TRG Clonality Multiplex PCR Aids Management of Patients with Enteropathic Diseases, including from Formaldehyde-Fixed, Paraffin-Embedded Tissues

Celiac disease is a chronic inflammation of the small intestine with villous atrophy that can become refractory to a gluten-free diet. Two categories of refractory celiac disease can be distinguished by the phenotype of intraepithelial lymphocytes and the status of TRG genes. Their distinction is important because 30% to 50% of type II but only 0% to 14% of type I evolve to an aggressive enteropathy-associated T-cell lymphoma and therefore require intensive treatment. Currently, differential diagnosis integrates immunohistochemistry, immunophenotyping, and TRG clonality analyses, but each has limitations. A single-tube multiplex TRG PCR (ECN) was prospectively compared to an in-house two-tube TRG PCR (N2T) in 73 samples, including 67 cryopreserved intestine tissues. Thirteen formalin-fixed, paraffin-embedded (FFPE) samples were also analyzed retrospectively. The ECN PCR had comparable efficiency to detect major clonal rearrangements in highly infiltrated tissues from T-cell lymphoproliferative disorders and type II refractory celiac disease and to detect the persistence of minor clones in type II refractory celiac disease follow-up samples. The ECN PCR abolished the risk of amplification of false-positive weak clonal rearrangements in cryopreserved specimens and allowed improved detection of clonal rearrangements in DNA from FFPE samples. The ECN PCR allows robust assessment of cryopreserved and FFPE digestive tissues at diagnosis and follow-up of enteropathies with villous atrophy, thus guiding therapeutic management.

Clinical Impact of the 2016 Update to the WHO Lymphoma Classification

OPINION STATEMENT

The 2016 revision of the WHO classification of lymphoid neoplasms includes new entities along with a clearer definition of provisional and definitive subtypes based on better understanding of the molecular drivers of lymphomas. These changes impact current treatment paradigms and provide a framework for future clinical trials. Additionally, this update recognizes several premalignant or predominantly indolent entities and underscores the importance of avoiding unnecessarily aggressive treatment in the latter subsets.

Peripheral T-cell lymphoma - are we making progress?

Peripheral T cell lymphoma (PTCL) is a rare subtype of non-Hodgkin lymphoma. PTCLs are heterogeneous in terms of biology, but generally have more aggressive features and poorer outcomes than aggressive B-cell lymphomas when treated with combination chemotherapy. While the best long-term results are still seen with intensive chemotherapeutic approaches, significant progress has been made with molecular profiling identifying genetic drivers of PTCL that could serve as therapeutic targets. Tailoring therapy to different subtypes of PTCL may lead to more individualized approaches with the hope of improved outcomes. In this paper, we review current therapies for treatment of PTCL, newly identified molecular markers, and the role of emerging therapy and novel combinations of existing agents.

The Role of Activator Protein-1 (AP-1) Family Members in CD30-Positive Lymphomas

The Activator Protein-1 (AP-1) transcription factor (TF) family, composed of a variety of members including c-JUN, c-FOS and ATF, is involved in mediating many biological processes such as proliferation, differentiation and cell death. Since their discovery, the role of AP-1 TFs in cancer development has been extensively analysed. Multiple in vitro and in vivo studies have highlighted the complexity of these TFs, mainly due to their cell-type specific homo- or hetero-dimerization resulting in diverse transcriptional response profiles. However, as a result of the increasing knowledge of the role of AP-1 TFs in disease, these TFs are being recognized as promising therapeutic targets for various malignancies. In this review, we focus on the impact of deregulated expression of AP-1 TFs in CD30-positive lymphomas including Classical Hodgkin Lymphoma and Anaplastic Large Cell Lymphoma.

SYK expression in monomorphic epitheliotropic intestinal T-cell lymphoma

Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), formerly known as type II enteropathy associated T-cell lymphoma (type II EATL), is a rare, aggressive primary intestinal T-cell lymphoma with a poor prognosis and an incompletely understood pathogenesis. We collected 40 cases of MEITL and 27 cases of EATL, formerly known as type I EATL, and comparatively investigated the T-cell receptor (TCR) itself and associated signaling molecules using immunohistochemistry, amplicon deep sequencing and bisulfite pyrosequencing. The TCR showed both an αβ-T-cell origin (30%) and a γδ-T-cell derivation (55%) resulting in a predominant positive TCR phenotype in MEITL compared with the mainly silent TCR phenotype in EATL (65%). The immunohistochemical expression of the spleen tyrosine kinase (SYK) turned out to be a distinctive feature of MEITL (95%) compared with EATL (0%). Aberrant SYK overexpression in MEITL is likely caused by hypomethylation of the SYK promoter, while no common mutations in the SYK gene or in its promoter could be detected. Using amplicon deep sequencing, mutations in DNMT3A, IDH2, and TET2 were infrequent events in MEITL and EATL. Immunohistochemical expression of linker for activation of T-cells (LAT) subdivided MEITL into a LAT expressing subset (33%) and a LAT silent subset (67%) with a potentially earlier disease onset in LAT-positive MEITL.

Perforation of the small intestine caused by enteropathy-associated T cell lymphoma

Enteropathy-associated T cell lymphoma is a rare lymphoma specific to the gastrointestinal system, arising from intraepithelial T lymphocytes, that is often associated with celiac disease. We report a 53-year-old female patient with no previous disease who presented with severe abdominal pain. Physical examination revealed diffuse abdominal tenderness and abdominal guarding and the patient underwent emergency surgery with a diagnosis of acute abdomen. During the operation, a 20-cm mass was found located on Treitz ligament, invading the duodenum and pancreatic head and perforating the jejunum. Histologically, medium-sized monomorphic atypical lymphocyte infiltration with dark nucleus and narrow cytoplasm was seen in the layers of mucosa, submucosa, muscular wall, and serosa of the duodenum. The final pathological diagnosis was "enteropathy-associated T cell lymphoma type 2" based on immunohistochemical and serological findings. Based on the World Health Organization 2008 criteria, enteropathy-associated T cell lymphoma has two subtypes. Type 1 enteropathy-associated T cell lymphoma is associated with celiac disease and has HLA DQ2 and HLA DQ8 genotype. Enteropathy-associated T cell lymphoma 2 enteropathy-associated T cell lymphoma seldom occurs and is not associated with celiac disease.

Enteropathy-Associated T-Cell Lymphoma

Enteropathy-associated T-cell lymphoma is a rare neoplasm with uniformly aggressive features that arises from intestinal T-cells. There is strong evidence supporting its association as a dire complication of celiac disease. The clinical presentation can vary from malabsorption and abdominal pain to an acute abdominal emergency. Originally, it was divided into types I and II in World Health Organization (WHO) classification schemes, reflective of epidemiology and differences in clinicopathologic features. The debate over the degree of separation of the two types is ongoing as new data emerges regarding the pathogenetics. The low incidence and variable patient factors are major barriers in conducting clinical trials and establishing standard treatment regimens. Yet, the collective experience demonstrates favorable outcomes with combination chemotherapy followed by an autologous hematopoietic stem cell transplant in patients who can tolerate such treatment. The prognosis remains dismal; thus, future research studies are warranted to identify effective novel therapies that can improve outcomes in this rare disease entity.

Monomorphic epitheliotropic intestinal T-cell lymphoma in pleural effusion: A case report

Dissemination of lymphomas in serous effusions is quite common. Cytology aims to contribute in the clinical management of haematologic patients, providing an accurate and rapid diagnosis. Ancillary techniques such as immunocytochemistry and flow cytometry are essential to classify the lymphoma entity. Comprehensive awareness of the clinical picture and previous histologic documentation are essential for a lymphomatous effusion diagnosis. We report an unusual case of monomorphic epitheliotropic intestinal T-cell lymphoma, formerly known as enteropathy associated T-cell lymphoma (EATL) type II, spreading in the pleural cavity. Cell morphology and immunohistochemistry of the pleural fluid were consistent with the histology of a jejunal tumor previously excised. Flow cytometry data were consistent, though not pathognomonic for the disease. Serous effusions with evidence of lymphoma involvement should be thoroughly examined with cytology and adjuvant techniques to provide diagnosis for proper therapeutic strategies.

The aggressive peripheral T-cell lymphomas: 2017

BACKGROUND

T-cell lymphomas make up approximately 10%-15% of lymphoid malignancies. The frequency of these lymphomas varies geographically, with the highest incidence in parts of Asia.

DIAGNOSIS

The diagnosis of aggressive peripheral T-cell lymphoma (PTCL) is usually made using the World Health Organization classification. The ability of hematopathologists to reproducibly diagnose aggressive PTCL is lower than that for aggressive B-cell lymphomas, with a range of 72%-97% for the aggressive PTCLs. Risk Stratification: Patients with aggressive PTCL are staged using the Ann Arbor Classification. Although somewhat controversial, positron emission tomography scans seem to be useful as they are in aggressive B-cell lymphomas. The specific subtype of aggressive PTCL is an important risk factor with the best survival seen in anaplastic large-cell lymphoma-particularly young patients with the anaplastic lymphoma kinase positive subtype.

RISK-ADAPTED THERAPY

Anaplastic large-cell lymphoma is the only subgroup to have a good response to a CHOP-like regimen. Angioimmunoblastic T-cell lymphoma has a prolonged disease-free survival in only ∼20% of patients, but younger patients who have an autotransplant in remission seem to do better. PTCL-not otherwise specified is not one disease. Anthracycline-containing regimens have disappointing results, and a new approach is needed. Natural killer/T-cell lymphoma localized to the nose and nasal sinuses seems to be best treated with radiotherapy-containing regimens and the majority of patients are cured. Enteropathy-associated PTCL and hepatosplenic PTCL are rare disorders with a generally poor response to therapy although selected patients with enteropathy- associated PTCL seem to benefit from intensive therapy.

Enteropathy-associated T cell lymphoma subtypes are characterized by loss of function of SETD2

Enteropathy-associated T cell lymphoma (EATL) is the most common oncologic complication of celiac disease. Moffitt and colleagues identify novel EATL-defining mutations in SETD2, as well as clinically relevant mutations in the JAK-STAT pathway.

Enteropathy-associated T cell lymphoma (EATL) is a lethal, and the most common, neoplastic complication of celiac disease. Here, we defined the genetic landscape of EATL through whole-exome sequencing of 69 EATL tumors. SETD2 was the most frequently silenced gene in EATL (32% of cases). The JAK-STAT pathway was the most frequently mutated pathway, with frequent mutations in STAT5B as well as JAK1, JAK3, STAT3, and SOCS1. We also identified mutations in KRAS, TP53, and TERT. Type I EATL and type II EATL (monomorphic epitheliotropic intestinal T cell lymphoma) had highly overlapping genetic alterations indicating shared mechanisms underlying their pathogenesis. We modeled the effects of SETD2 loss in vivo by developing a T cell–specific knockout mouse. These mice manifested an expansion of γδ T cells, indicating novel roles for SETD2 in T cell development and lymphomagenesis. Our data render the most comprehensive genetic portrait yet of this uncommon but lethal disease and may inform future classification schemes.

Uncommon Variants of T-Cell Lymphomas

Peripheral T-cell lymphomas represent 10% to 15% of non-Hodgkin lymphomas and comprise more than 20 different entities. Treatment of very rare T-cell lymphomas can be challenging because there are no large or randomized studies to guide clinical decision making, and treatment paradigms are often based on small series or imperfect data. Although a strict algorithm cannot be written with certainty, through the literature that exists and clinical experience, themes and principles of approaches do emerge that when coupled with clinical judgment allow reasonable and logical decisions.

Lymphoma classification update: T-cell lymphomas, Hodgkin lymphomas, and histiocytic/dendritic cell neoplasms

INTRODUCTION

Lymphomas are classified based on the normal counterpart, or cell of origin, from which they arise. Because lymphocytes have physiologic immune functions that vary both by lineage and by stage of differentiation, the classification of lymphomas arising from these normal lymphoid populations is complex. Recent genomic data have contributed additional depth to this complexity. Areas covered: Lymphoma classification follows the World Health Organization (WHO) system, which reflects international consensus and is based on pathological, genetic, and clinical factors. The present review focuses on the classification of T-cell lymphomas, Hodgkin lymphomas, and histiocytic and dendritic cell neoplasms, summarizing changes reflected in the 2016 revision to the WHO classification. These changes are critical to hematologists and other clinicians who care for patients with these disorders. Expert commentary: Lymphoma classification is a continually evolving field that needs to be responsive to new clinical, pathological, and molecular understanding of lymphoid neoplasia. Among the entities covered in this review, the 2016 revisions in the WHO classification particularly impact T-cell lymphomas, including a new umbrella category of T-follicular helper cell-derived lymphomas and evolving recognition of indolent T-cell lymphomas and lymphoproliferative disorders.

Recurrent Cytogenetic Abnormalities in Non-Hodgkin's Lymphoma and Chronic Lymphocytic Leukemia

Characteristic chromosomal translocations are found to be associated with subtypes of B-cell non-Hodgkin lymphoma (NHL), for example t(8;14)(q24;q32) and Burkitt lymphoma, t(14;18)(q32;q21) and follicular lymphoma, and t(11;14)(q13;q32) in mantle cell lymphoma. Only few recurrent cytogenetic aberrations have been identified in the T-cell NHL and the best known is the ALK gene translocation t(2;5)(p23;q35) in anaplastic large cell lymphoma. Since lymph node or other tissue is seldom submitted for conventional cytogenetics study, alternative approaches for translocation detection are polymerase chain reaction (PCR) or fluorescence in situ hybridization (FISH). FISH is more sensitive than PCR in the detection of lymphoma translocations since directly labeled large FISH probes that span the translocation breakpoints are used. Although the recurrent chromosomal abnormalities in NHL are not completely sensitive and specific for disease entities, unlike the scenario in acute leukemia, cytogenetic and molecular genetic study is commonly used to aid lymphoma diagnosis and classification. Currently, the main clinical utility is in the employment of interphase FISH panels to predict disease aggressiveness to guide therapy, for example identification of double-hit lymphoma, or in prognostication, for example risk-stratification in chronic lymphocytic leukemia. The recent application of high-throughput sequencing to NHL not only advances the understanding of disease pathogenesis and classification, but allows the discovery of new drug targets, such as BRAF gene inhibition in hairy cell leukemia. Coupled with the increasing availability of novel molecular targeted therapeutic agents, the hope for the future is to translate the genetics and genomics information to achieve personalized medicine in NHL.

Refractory celiac disease

Refractory celiac disease (RCD) affects patients who have failed to heal after 6-12 months of a strict gluten-free diet (GFD) and when other causes of symptoms (including malignancy) have been ruled out. It may also occur in patients who previously had responded to a long-term GFD. RCD may be categorized as RCD1 (normal immunophenotype) and RCD2 (aberrant immunophenotype). RCD1 usually responds to a continued GFD, nutritional support, and therapeutic agents such as corticosteroids. In contrast, clinical response in RCD2 is incomplete and prognosis is often poor. RCD (particularly RCD2) is associated with serious complications, such as ulcerative jejunitis and enteropathy-associated T-cell lymphoma (EATL). Strict clinical and laboratory criteria should be used to diagnose RCD and specialized tests for aberrancy and clonality should be interpreted in the context of their sensitivity and specificity. Adequate nutritional support and anti-inflammatory treatment may even allow patients with RCD2 to attain a clinical remission.

Identification of Mucosa-Invading and Intravascular Bacteria in Feline Small Intestinal Lymphoma

Persistent bacterial infections of the gastrointestinal mucosa are causally linked to gastric carcinoma and mucosa-associated lymphoid tissue (MALT) lymphoma in people and laboratory animals. We examined the relationship of mucosa-associated bacteria to alimentary lymphoma in cats. Intestinal biopsies from 50 cats with alimentary lymphoma (small cell, n = 33; large cell, n = 17) and 38 controls without lymphoma (normal to minimal change on histopathology, n = 18; lymphocytic-plasmacytic enteritis, n = 20) were evaluated. The number and spatial distribution of bacteria (ie, in luminal cellular debris, villus-associated mucus, adherent to epithelium, mucosal invasion, intravascular, or serosal) were determined by fluorescence in situ hybridization with the eubacterial probe EUB-338. Mucosa-invasive bacteria were more frequently observed in cats with large cell lymphoma (82%, P ≤ .001) than in cats with small cell lymphoma (18%), normal to minimal change on histopathology, and lymphocytic-plasmacytic enteritis (3%). Intravascular bacteria were observed solely in large cell lymphoma (29%), and serosal colonization was more common in cats with large cell lymphoma (57%) than with small cell lymphoma (11%, P ≤ .01), normal to minimal change (8%, P ≤ .01), and lymphocytic-plasmacytic enteritis (6%, P ≤ .001). The high frequency of invasive bacteria within blood vessels and serosa of cats with large cell lymphoma may account for the sepsis-related complications associated with large cell lymphoma and inform clinical management. Further studies are required to determine the role of intramucosal bacteria in the etiopathogenesis of feline alimentary lymphoma.

Type II enteropathy-associated T-cell lymphoma features a unique genomic profile with highly recurrent SETD2 alterations

Enteropathy-associated T-cell lymphoma (EATL), a rare and aggressive intestinal malignancy of intraepithelial T lymphocytes, comprises two disease variants (EATL-I and EATL-II) differing in clinical characteristics and pathological features. Here we report findings derived from whole-exome sequencing of 15 EATL-II tumour-normal tissue pairs. The tumour suppressor gene SETD2 encoding a non-redundant H3K36-specific trimethyltransferase is altered in 14/15 cases (93%), mainly by loss-of-function mutations and/or loss of the corresponding locus (3p21.31). These alterations consistently correlate with defective H3K36 trimethylation. The JAK/STAT pathway comprises recurrent STAT5B (60%), JAK3 (46%) and SH2B3 (20%) mutations, including a STAT5B V712E activating variant. In addition, frequent mutations in TP53, BRAF and KRAS are observed. Conversely, in EATL-I, no SETD2, STAT5B or JAK3 mutations are found, and H3K36 trimethylation is preserved. This study describes SETD2 inactivation as EATL-II molecular hallmark, supports EATL-I and -II being two distinct entities, and defines potential new targets for therapeutic intervention.

Multiple lesions of gastrointestinal tract invasion by monomorphic epitheliotropic intestinal T-cell lymphoma, accompanied by duodenal and intestinal enteropathy-like lesions and microscopic lymphocytic proctocolitis: a case series

Background

In East Asia, monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), previously known as type II enteropathy-associated T-cell lymphoma (EATL), occurs more frequently than type I EATL, and coeliac disease is rare.

Case presentation

Here we present four cases of MEITL in Japanese patients, including the endoscopic and pathological findings of their duodenal and colorectal lesions. Tumor specimens obtained from duodenal, intestinal, and colorectal biopsies in all four patients showed a diffuse intramucosal infiltration of small to/or medium-sized lymphoma cells and numerous atypical intraepithelial lymphocytes (IELs). These cells were immunohistologically positive for CD103, CD3, CD7, CD8, CD56, and T-cell intracellular antigen-1. Upper and lower gastrointestinal and antegrade double-balloon endoscopy revealed foci of edematous mucosa, with or without villous atrophy, in the non-neoplastic mucosa. Histological studies demonstrated duodenal and intestinal enteropathy-like lesions as well as microscopic (lymphocytic) proctocolitis with increased CD3- and CD8-positive and CD56-negative T-IELs in all four patients. The clinicopathological findings of the non-neoplastic lesions were similar to those characteristic of coeliac disease, suggesting that variants of coeliac disease may be present in the prodromal lesions of MEITL.

Conclusions

Our study supports the need for random gastrointestinal biopsies to determine tumor spread, the features of MEITL in the particular patients, and the presence of prodromal non-neoplastic lesions.

Indolent T- and NK-cell lymphoproliferative disorders of the gastrointestinal tract: a review and update

Primary gastrointestinal (GI) T- and NK-cell lymphomas are usually aggressive neoplasms associated with high morbidity and mortality. Over the past two decades, however, cases of primary GI lymphoproliferative disorders (LPDs) or lymphomas of T- or NK-cell derivation with indolent behavior have been reported. These LPDs are rare and they can be challenging to diagnose as they share clinical and pathological features with both, inflammatory disorders and aggressive T- and NK-cell lymphomas. Primary, indolent clonal T-cell proliferations of the GI tract, which can be CD4+, CD8+ or CD4- CD8-, have been included as a provisional entity in the newly revised World Health Organization (WHO) classification of lymphoid neoplasms and designated 'indolent T-cell LPD of the GI tract'. It is currently unclear whether the indolent NK-cell LPDs represent reactive or neoplastic proliferations. In this review, we describe the clinical, morphologic, immunophenotypic and genetic features of indolent GI T- and NK-cell LPDs and provide guidance in differentiating them from other inflammatory and neoplastic diseases. We believe that greater awareness of these LPDs amongst physicians and the research community will lead to timely and accurate diagnoses, stimulate investigations into the pathogenetic mechanisms underlying different entities thereby enhancing our understanding of disease biology and enable the development of effective therapeutic regimens. Copyright © 2016 John Wiley & Sons, Ltd.

The 2016 revision of the World Health Organization classification of lymphoid neoplasms

A revision of the nearly 8-year-old World Health Organization classification of the lymphoid neoplasms and the accompanying monograph is being published. It reflects a consensus among hematopathologists, geneticists, and clinicians regarding both updates to current entities as well as the addition of a limited number of new provisional entities. The revision clarifies the diagnosis and management of lesions at the very early stages of lymphomagenesis, refines the diagnostic criteria for some entities, details the expanding genetic/molecular landscape of numerous lymphoid neoplasms and their clinical correlates, and refers to investigations leading to more targeted therapeutic strategies. The major changes are reviewed with an emphasis on the most important advances in our understanding that impact our diagnostic approach, clinical expectations, and therapeutic strategies for the lymphoid neoplasms.

Zebras and hen's teeth: recognition and management of rare T and NK lymphomas

Although all the peripheral T-cell lymphomas are uncommon, there are some entities that are truly rare. Subtypes, such as enteropathy-associated T-cell lymphoma, hepatosplenic T-cell lymphoma, extranodal NK/T-cell lymphoma, and subcutaneous panniculitis-like T-cell lymphoma, have an approximate annual incidence in United States of <500 each. In these very rare subtypes, there is limited data to guide clinical decision-making. As such, our treatment decisions are often based on extrapolation, case series, personal experience, and biases. We summarize the existing data regarding initial management of these entities and compare how that management follows paradigms established for the more common T-cell lymphomas.

[Molecular pathogenesis of peripheral T cell lymphoma (2): extranodal NK/T cell lymphoma, nasal type, adult T cell leukemia/lymphoma and enteropathy associated T cell lymphoma]

Peripheral T-cell lymphomas (PTCL) belong to the group of non-Hodgkin lymphoma and particularly that of mature T /NK cells lymphoproliferative neoplasms. The 2008 WHO classification describes different PTCL entities with varying prevalence. With the exception of histologic subtype "ALK positive anaplastic large cell lymphoma", PTCL are characterized by a poor prognosis. The mechanisms underlying the pathogenesis of these lymphomas are not yet fully understood, but development of genomic high-throughput analysis techniques now allows to extensively identify the molecular abnormalities present in tumor cells. This review aims to summarize the current knowledge and recent advances about the molecular events occurring at the origin or during the natural history of main entities of PTCL. The first part published in the October issue was focused on the three more frequent entities, i.e. angioimmunoblastic T-cell lymphoma, peripheral T-cell lymphoma, not otherwise specified, and anaplastic large cell lymphoma. The second part presented herein will describe other subtypes less frequent and of poor prognosis : extranodal NK/T-cell lymphoma, nasal type, adult T-cell leukemia/lymphoma, and enteropathy-associated T-cell lymphoma.

Is ALK-gene rearrangement overlooked in primary gastrointestinal T-cell lymphomas? About two cases

A 41-year-old male patient with a history of ankylosing spondylitis and Crohn disease, treated with immunomodulators and disease-modifying drugs, was diagnosed with a primary intestinal T-cell lymphoma that followed a 7.5-year-course. This transmural proliferation lacked cytological characteristics of anaplastic large cell lymphoma (ALCL), and was CD8-positive, and CD30- and anaplastic lymphoma kinase (ALK)-negative by immunohistochemistry (IHC). However, ALK-gene rearrangement (ALK-gr) was detected by fluorescence in situ hybridization (FISH) in both initial and persistent disease. The possibility of indolent T-cell lymphoproliferative disease of the gastrointestinal tract with atypical features (transmural involvement) related to ALK-gr was suggested. A previous case of aggressive 'enteropathy-associated ALCL' in the context of celiac disease was recently reported, which also lacked anaplastic morphology, and where CD30 and ALK expression was incidentally demonstrated by IHC, and ALK-gr subsequently confirmed by FISH. These two recent cases represent two distinct rare entities pertaining to the group of primary intestinal T-cell lymphomas, and they both show unexpected ALK-gr. This suggests that ALK-gr has been overlooked in the group of primary intestinal T-cell lymphomas. Performing IHC and FISH tests for ALK-gr in primary gastrointestinal T-cell lymphomas might be of importance, particularly with the advancement of targeted therapy that could impact treatment and prognosis.

Genomic and immunohistochemical profiles of enteropathy-associated T-cell lymphoma in Japan

Enteropathy-associated T-cell lymphoma (EATL) is a rare primary T-cell lymphoma of the digestive tract. EATL is classified as either Type I, which is frequently associated with and thought to arise from celiac disease and is primarily observed in Northern Europe, and Type II, which occurs de novo and is distributed all over the world with predominance in Asia. The pathogenesis of EATL in Asia is unknown. We aimed to clarify the histological and genomic profiles of EATL in Japan in a homogeneous series of 20 cases. The cases were characterized by immunohistochemistry, high-resolution oligonucleotide microarray, and fluorescence in situ hybridization (FISH) at five different loci: 1q21.3 (CKS1B), 6q16.3 (HACE1), 7p22.3 (MAFK), 9q33.3 (PPP6C), and 9q34.3 (ASS1, CARD9) using formalin-fixed paraffin-embedded sections. The histological appearance of EATL ranged from medium- to large-sized cells in 13 cases (65%), small- to medium-sized cells in five cases (25%), and medium-sized in two cases (10%). The immunophenotype was CD2(+) (60%), CD3ɛ(+) (100%), CD4(+) (10%), CD7(+) (95%), CD8(+) (80%), CD56(+) (85%), TIA-1(+) (100%), Granzyme B(+) (25%), T-cell receptor (TCR)β(+) (10%), TCRγ(+) (35%), TCRγδ(+) (50%), and double negative for TCR (six cases, 30%). All cases were EBER(-). The genomic profile showed recurrent copy number gains of 1q32.3, 4p15.1, 5q34, 7q34, 8p11.23, 9q22.31, 9q33.2, 9q34.13, and 12p13.31, and losses of 7p14.1. FISH showed 15 patients (75%) with a gain of 9q34.3 with good correlation with array comparative genomic hybridization. EATL in Japan is characterized by non-monomorphic cells with a cytotoxic CD8(+) CD56(+) phenotype similar to EATL Type II. The genomic profile is comparable to EATL of Western countries, with more similarity to Type I (gain of 1q and 5q) rather than Type II (gain of 8q24, including MYC). The 9q34.3 gain was the most frequent change confirmed by FISH irrespective of the cell origin of αβ-T-cells and γδ-T-cells.

The aggressive peripheral T-cell lymphomas: 2015

BACKGROUND

T-cell lymphomas make up approximately 10%-15% of lymphoid malignancies. The frequency of these lymphomas varies geographically, with the highest incidence in parts of Asia.

DIAGNOSIS

The diagnosis of aggressive peripheral T-cell lymphoma (PTCL) is usually made using the World Health Organization classification. The ability of hematopathologists to reproducibly diagnosis aggressive PTCL is lower than that for aggressive B-cell lymphomas, with a range of 72%-97% for the aggressive PTCLs.

RISK STRATIFICATION

Patients with aggressive PTCL are staged using the Ann Arbor Classification. Although somewhat controversial, positron emission tomography scans seem to be useful as they are in aggressive B-cell lymphomas. The most commonly used prognostic index is the International Prognostic Index. The specific subtype of aggressive PTCL is an important risk factor, with the best survival seen in anaplastic large-cell lymphoma-particularly young patients with the anaplastic lymphoma kinase positive subtype.

RISK-ADAPTED THERAPY

Anaplastic large-cell lymphoma is the only subgroup to have a good response to a CHOP-like regimen. Angioimmunoblastic T-cell lymphoma has a prolonged disease-free survival in only ~20% of patients, but younger patients who have an autotransplant in remission seem to do better. PTCL-not otherwise specified is not one disease. Anthracycline-containing regimens have disappointing results, and a new approach is needed. Natural killer/T-cell lymphoma localized to the nose and nasal sinuses seems to be best treated with radiotherapy-containing regimens. Enteropathy-associated PTCL and hepatosplenic PTCL are rare disorders with a generally poor response to therapy, although selected patients with enteropathy-associated PTCL seem to benefit from intensive therapy.

Novel variant of EATL evolving from mucosal γδ-T-cells in a patient with type I RCD

Objectives

Enteropathy associated T-cell lymphoma (EATL) is a rare non-Hodgkin lymphoma that may complicate coeliac disease and typically occurs in patients with refractoriness to the gluten-free diet. The majority of these patients harbour a clonal expansion of intraepithelial lymphocytes (IELs) with an aberrant phenotype in the small intestine which are thus considered as the ‘precursor’ lymphoma cells. We describe a 51-year-old female patient with refractory coeliac disease (RCD) who developed an EATL with manifestations in the proximal small intestine and in a mesenteric lymph node that did not evolve from regular type ‘aberrant’ αβ-T-cells but rather from a clonal expansion of γδ-T-cells.

Methods

Duodenal biopsies and lymphoma tissue from a patient with refractory coeliac disease whom developed an EATL were extensively studied by immunophenotypical, T-cell receptor immunogenetic and chromosomal analysis.

Results

Flow cytometric analysis of duodenal IELs revealed an unusual large clonal expansion of CD30 negative γδ-T-cells in a patient with RCD. When the patient clinically deteriorated 18 months later, a substantial part (30%) of this cell population did express CD30. In addition, identical immunogenetic aberrancies had developed in a prehepatic lymph node.

Conclusions

We here report on a case of extraintestinal EATL that originated from a clonal γδ-IEL population rather than from aberrant IEL. This EATL displayed a distinctive pattern of immunophenotypical, T-cell receptor immunogenetic and chromosomal aberrancies as compared to classical EATL, defining this lymphoma as a novel variant of EATL.

Profile of CD103 expression in T-cell neoplasms: immunoreactivity is not restricted to enteropathy-associated T-cell lymphoma

Intestinal intraepithelial T lymphocytes express the α E subunit of integrin αEβ7, which is detected by antibodies to CD103. Accordingly, within T-cell neoplasms, CD103 reactivity has most frequently been reported in enteropathy-associated T-cell lymphomas, which are postulated to arise from intestinal intraepithelial T lymphocytes. However, prior studies of CD103 expression in T-cell neoplasms have been limited by the requirement for fresh or frozen tissue, given the historic lack of an antibody to CD103 for use in paraffin-embedded sections. Thus, a thorough assessment of CD103 expression in a broad spectrum of T-cell neoplasms as categorized by the current classification system has not yet been performed. This study uses a newly described antibody to define the profile of CD103 immunoreactivity in paraffin sections of a wide variety of T-cell neoplasms (184 cases). Overall, 22 T-cell neoplasms (12%) were CD103 positive, including 7 of 15 gastrointestinal lymphomas (3.8% of total cases; 46% of gastrointestinal cases). In intestinal cases, CD103 positivity did not correlate with morphology, presence or absence of enteropathy, or immunohistochemical profile. A history of celiac disease was not documented in any case. Frequent but inconsistent reactivity was also noted for adult T-cell leukemia/lymphoma with 4 of 10 cases (40%) positive. In the remaining T-cell neoplasms representing most entities within the current World Health Organization classification, CD103 reactivity was sporadically observed in 11 of 159 cases (6.9%). CD103 positivity is an unusual feature in T-cell neoplasms and tends to occur in gastrointestinal lymphomas and adult T-cell leukemia/lymphoma but is not a consistent characteristic of these neoplasms.

Immunohistochemistry as a valuable tool to assess CD30 expression in peripheral T-cell lymphomas: high correlation with mRNA levels

The extended use of brentuximab-vedotin was reported for CD30(+) nonanaplastic peripheral T-cell lymphomas (PTCLs) with promising efficacy. CD30 status assessment is thus a critical factor for therapeutic decision, but the reliability of immunohistochemistry (IHC) in evaluating its expression remains to be defined. This prompted us to investigate the correlation between semiquantitative CD30 protein assessment by IHC and messenger RNA (mRNA) assessment by microarrays in a cohort of 376 noncutaneous PTCLs representative of the main entities. By IHC, CD30 expression was heterogeneous across and within entities and significantly associated with large tumor cell size. In addition to 100% anaplastic large-cell lymphomas, 57% of other PTCL entities were CD30-positive at a 5% threshold. CD30 protein expression was highly correlated to mRNA levels. mRNA levels were bimodal, separating high from low CD30-expressing PTCL cases. We conclude that IHC is a valuable tool in clinical practice to assess CD30 expression in PTCLs.

Diagnosis and management of adult coeliac disease: guidelines from the British Society of Gastroenterology

A multidisciplinary panel of 18 physicians and 3 non-physicians from eight countries (Sweden, UK, Argentina, Australia, Italy, Finland, Norway and the USA) reviewed the literature on diagnosis and management of adult coeliac disease (CD). This paper presents the recommendations of the British Society of Gastroenterology. Areas of controversies were explored through phone meetings and web surveys. Nine working groups examined the following areas of CD diagnosis and management: classification of CD; genetics and immunology; diagnostics; serology and endoscopy; follow-up; gluten-free diet; refractory CD and malignancies; quality of life; novel treatments; patient support; and screening for CD.

Endoscopic and clinical analysis of primary T-cell lymphoma of the gastrointestinal tract according to pathological subtype

BACKGROUND AND AIM

Little is known about the clinicopathological characteristics of primary gastrointestinal T-cell lymphomas (PGITL). This study evaluated the clinical and endoscopic features of the pathological subtypes of PGITL.

METHODS

Forty-two lesions in 36 patients with PGITL were assessed, including 15 enteropathy-associated T-cell lymphomas (EATL), 13 peripheral T-cell lymphomas (PTCL), 10 NK/T-cell lymphomas (NK/TL), and four anaplastic large cell lymphomas (ALCL).

RESULTS

PTCL occurred more frequently in the stomach and duodenum and NK/TL more frequently in the small and large intestines (P = 0.009). The endoscopic features of the four subtypes were similar (P = 0.124). Fifteen of 41 lesions (36.6%) were Epstein-Barr virus (EBV) positive, with NK/TL more likely to be EBV positive than the other types (P < 0.001). First endoscopy and first computed tomography (CT) scan indicated that 65.4% and 51.4% of the lesions, respectively, were malignant, and that 43.2% and 42.3%, respectively, were GI lymphomas. The two modalities together correctly diagnosed about half of the lesions before biopsy. Intestinal perforation was associated with small bowel location (P < 0.001) and infiltrative type (P = 0.009), and was more common in NK/TL than in the other subtypes (P = 0.015). Multivariate analysis showed that higher international prognosis index (P = 0.008) and the presence of complications (P = 0.006) were associated with poor prognosis. Survival was poorer in patients with small bowel lesions than with lesions at other locations (P = 0.048).

CONCLUSIONS

The four main pathological types of PGITL differed in clinical characteristics. As PGITL was often not diagnosed by initial endoscopic or radiological examination, a high index of suspicion is necessary to ensure its early diagnosis.

Small intestinal CD4+ T-cell lymphoma is a heterogenous entity with common pathology features

BACKGROUND & AIMS

Little is known about intestinal CD4+ T-cell lymphoma; this rare malignancy is misdiagnosed frequently. We evaluated diagnostic criteria and factors that might affect its development and outcome.

METHODS

In a retrospective analysis, we analyzed medical records and intestinal specimens from 10 patients diagnosed with intestinal CD4+ T-cell lymphoma among 115 consecutive patients examined for severe enteropathy with villous atrophy. Samples were analyzed by histology, flow cytometry, and comparative genomic hybridization.

RESULTS

Small-intestine epithelial and lamina propria tissues from patients who presented with chronic diarrhea and malnutrition had variable levels of infiltration of CD3+ CD4+ T cells. Flow cytometry showed a high frequency of CD4+ intraepithelial cells, which frequently expressed a specific Vβ chain. T-cell receptor β clonality was confirmed by DNA sequencing. Two patients had HLA and serology results compatible with celiac disease and autoimmune enteropathy, respectively. Two patients were found to have antibodies against human T-cell leukemia virus and 2 patients had signs of a recent infection with the herpes viruses. Comparative genomic hybridization analyses showed heterogeneous chromosomal abnormalities. Symptoms were reduced in patients treated with steroids (n = 5), but not in patients given purine analogues or chemotherapy. Antibodies against CD52 produced clinical and histologic responses in 2 of 2 patients, whereas severe adverse effects developed in 1 patient. At the latest follow-up evaluation, all patients were alive.

CONCLUSIONS

There is much heterogeneity in the onset and genetic features of intestinal CD4+ T-cell lymphomas, despite their common presentation as indolent lymphoproliferations of the intestinal mucosa. Patients should be treated with steroids, and possibly antibodies against CD52 (for the most aggressive forms of this disorder).

Detailed clinicopathological characteristics and possible lymphomagenesis of type II intestinal enteropathy-associated T-cell lymphoma in Japan

Twenty-six Japanese cases of type II enteropathy-associated T-cell lymphoma (EATL) were examined. Multiple tumors throughout the small intestine were found in 15 patients (58%) and duodenal and colonic mucosal lesions in 8 and 6 cases, respectively. Histologically, intramucosal tumor spread and a zone of neoplastic intraepithelial lymphocytes (IELs) neighboring the main transmural tumors were detected in 20 (91%) and 17 (77%) of the 22 cases examined, respectively. Inside and outside the IEL zone, some degree of enteropathy with many reactive small IELs and villous atrophy was detected in 11 cases (50%). Immunohistologically, many CD56/CD8-positive small IELs were found in the enteropathic lesions of 4 (36%) and 7 (64%) of these 11 cases. Lymphoma cells expressed tyrosine kinase receptor c-Met, serial phosphorylated (p)-mitogen-activated protein kinase/extracellular signal-regulated kinase, c-Myc, and Bcl2 in 18 (78%), 21 (91%), 11 (42%), and 19 (73%) of the total cases, respectively. By fluorescence in situ hybridization, chromosomal loci 7q31 (c-Met) and 8q24 (c-Myc) were amplified in 11 (65%) and 12 (71%) of the 17 cases analyzed. Gain of 7q31 and c-Met expression were significantly (P < .01) higher than in peripheral CD8-positive T-cell or CD56-positive natural killer-cell lymphomas. Enteropathy was seen near the IEL zone in type II EATL, and activation of the c-Met, mitogen-activated protein kinase/extracellular signal-regulated kinase-mitogen-activated protein kinase pathway, and c-Myc-Bcl2-mediated cell survival may play important roles in lymphomagenesis, converting enteropathy to type II EATL. Seven cases in the early clinical stages I and II-1 showed significantly (P < .01) better prognoses than did those in the advanced stages. Early detection of the mucosal lesions and tumors may improve patient prognosis.

Molecular diagnostics of T-cell lymphoproliferative disorders

T-cell neoplasms include both mature T-cell leukemias and lymphomas and immature proliferations of precursor T cells. Molecular laboratories routinely assay suspected T-cell proliferations for evidence of clonality. In addition, some T-cell neoplasms are characterized by recurrent structural abnormalities that can be readily identified by such techniques as fluorescence in situ hybridization. New massively parallel sequencing technologies have led to the identification of numerous recurrent gene mutations in T-cell neoplasms. These findings are reviewed. As new technologies become implemented in molecular diagnostic laboratories and as targeted therapies are developed, it is anticipated that more extensive genomic characterization of T-cell neoplasms will be routinely performed in the future.

Classic versus type II enteropathy-associated T-cell lymphoma: diagnostic considerations

Enteropathy-associated T-cell lymphoma is a rare type of peripheral T-cell lymphoma that characteristically involves the jejunum or ileum. Awareness of the histologic and immunophenotypic features of this subtype of lymphoma is important for accurate subclassification. Enteropathy-associated T-cell lymphoma has 2 forms, classic and type II, with different clinical and pathologic features. The 2 types will be described and discussed, with an emphasis on how to differentiate these entities in routine practice.

The aggressive peripheral T-cell lymphomas: 2013

BACKGROUND

T-cell lymphomas make up approximately 10-15% of lymphoid malignancies. The frequency of these lymphomas varies geographically, with the highest incidence in parts of Asia.

DIAGNOSIS

The diagnosis of aggressive peripheral T-cell lymphoma (PTCL) is usually made using the WHO classification. The ability of hematopathologists to reproducibly diagnosis aggressive PTCL is lower than for aggressive B-cell lymphomas, with a range of 72-97% for the aggressive PTCLs.

RISK STRATIFICATION

Patients with aggressive PTCL are staged using the Ann Arbor Classification. Although somewhat controversial, PET scans appear to be useful as they are in aggressive B-cell lymphomas. The most commonly used prognostic index is the International Prognostic Index. The specific subtype of aggressive PTCL is an important risk factor, with the best survival seen in anaplastic large cell lymphoma-particularly young patients with the anaplastic lymphoma kinase positive subtype.

RISK ADAPTED THERAPY

Anaplastic large cell lymphoma is the only subgroup to have a good response to a CHOP-like regimen. Angioimmunoblastic T-cell lymphoma has a prolonged disease-free survival in only ~20% of patients, but younger patients who have an autotransplant in remission seem to do better. PTCL-NOS (not otherwise specified) is not one disease. Anthracycline containing regimens have disappointing results and a new approach is needed. NK/T-cell lymphoma localized to the nose and nasal sinuses seems to be best treated with radiotherapy containing regimens. Enteropathy associated PTCL and hepatosplenic PTCL are rare disorders with a generally poor response to therapy, although selected patients with enteropathy associated PTCL seem to benefit from intensive therapy.

An unusual presentation of EATL type 1: Emergency surgery due to life-threatening gastrointestinal bleeding

INTRODUCTION

Enteropathy-associated T-cell lymphoma (EATL) is a very rare malignancy. Reasons for hospital admission are variable.

PRESENTATION OF CASE

76 years old man admitted to emergency service with sudden and massive obscure gastrointestinal bleeding. There was no complaints in his history. After initial evaluation, emergency laparatomy had to be done. Bleeding lesion in proximal jejunum was resected. Histopathologically, the muscularis propria had abundant atypical lymphoid infiltrate in diffuse pattern. Atypical lymphoid cells expressed CD3 and CD30. The jejunal mucosa adjacent to the tumor showed effacement of normal villous architecture.

DISCUSSION

EATL is known to cause anemia as a result of chronic bleeding. However in this case, the bleeding was abundant, irreplaceable and requiring emergency surgery. To our knowledge it is not reported previously.

CONCLUSION

A sudden and massive gastrointestinal bleeding can be the first and unique sign of EATL.

Indolent small intestinal CD4+ T-cell lymphoma is a distinct entity with unique biologic and clinical features

Enteropathy-associated T-cell lymphomas (EATL) are rare and generally aggressive types of peripheral T-cell lymphomas. Rare cases of primary, small intestinal CD4+ T-cell lymphomas with indolent behavior have been described, but are not well characterized. We describe morphologic, phenotypic, genomic and clinical features of 3 cases of indolent primary small intestinal CD4+ T-cell lymphomas. All patients presented with diarrhea and weight loss and were diagnosed with celiac disease refractory to a gluten free diet at referring institutions. Small intestinal biopsies showed crypt hyperplasia, villous atrophy and a dense lamina propria infiltrate of small-sized CD4+ T-cells often with CD7 downregulation or loss. Gastric and colonic involvement was also detected (n = 2 each). Persistent, clonal TCRβ gene rearrangement products were detected at multiple sites. SNP array analysis showed relative genomic stability, early in disease course, and non-recurrent genetic abnormalities, but complex changes were seen at disease transformation (n = 1). Two patients are alive with persistent disease (4.6 and 2.5 years post-diagnosis), despite immunomodulatory therapy; one died due to bowel perforation related to large cell transformation 11 years post-diagnosis. Unique pathobiologic features warrant designation of indolent small intestinal CD4+ T-cell lymphoma as a distinct entity, greater awareness of which would avoid misdiagnosis as EATL or an inflammatory disorder, especially celiac disease.

Enteropathy associated T cell lymphoma in celiac disease: a large retrospective study

INTRODUCTION

Prognosis of enteropathy-associated T cell lymphoma is poor but predictors of survival remain ill-defined. How clinical presentation, pathological features and therapies influence outcome was evaluated in 37 thoroughly characterized patients with celiac disease and T-cell lymphoma.

PATIENTS AND METHODS

Medical files were studied retrospectively. Lymphoma and intestinal mucosa were analysed by histopathology, multiplex PCR and intestinal intraepithelial lymphocytes phenotyping. Survival and prognostic factors were analysed using Kaplan-Meier curves with Logrank test and Cox Model.

RESULTS

Lymphoma complicated non clonal enteropathy, celiac disease (n=15) and type I refractory celiac disease (n=2) in 17 patients and clonal type II refractory celiac disease in 20 patients. Twenty-five patients underwent surgery with resection of the main tumour mass in 22 cases. In univariate analysis, non clonal celiac disease, serum albumin level>21.6g/L at diagnosis, chemotherapy and surgical resection predicted good survival (p=0.0007, p<0.0001, p<0.0001, p<0.0001, respectively). In multivariate analysis, serum albumin level>21.6g/L, chemotherapy and reductive surgery were all significantly associated with increased survival (p<0.002, p<0.03, p<0.03, respectively).

CONCLUSIONS

Our study underlines the prognostic value of celiac disease type in patients with T-cell lymphoma, and suggests that a combination of nutritional, chemotherapy and reductive surgery may improve survival.