Gastrointestinal lymphoma: where morphology meets molecular biology

Histological criteria for selecting patients who need clonality test for non-gastric MALT lymphoma diagnosis

The histological diagnosis of extranodal marginal zone lymphoma of the mucosa-associated lymphoid tissue (MALT lymphoma) is difficult for pathologists. Recently, digital pathology systems have been widely used to provide tools that can objectively measure lesions on slides. In this study, we measured the extent of marginal zone expansion in suspected MALT lymphoma cases and compared the results with those of a molecular clonality test. In total, 115 patients who underwent an IGH gene rearrangement test for suspected MALT lymphoma were included in this study. All cases were histologically classified into three patterns; "small lymphoid aggregates with no germinal center (Pattern 1)," "lymphoid follicles with germinal center (Pattern 2)" and " fused marginal zone or diffuse small lymphocytic proliferation (Pattern 3)." The proportions of monoclonality in Pattern 1, 2, and 3 were 25.0%, 55.0%, and 97.9%, respectively. The ratios of marginal zone thickness to germinal center diameter and entire lymphoid follicle area to germinal center area were measured in Pattern 2 cases using a digital pathology system. Combining the width cutoff of 1.5 and the areal cutoff of 3.5, the sensitivity, specificity, positive predictive value, and negative predictive value for MALT lymphoma were 96.97%, 70.37%, 80.00%, and 95.00%, respectively. In conclusion, through objective measurement of the marginal zone, suspected cases of MALT lymphoma requiring a molecular clonality test can be effectively selected.

Refractory celiac disease and its mimickers: a review on pathogenesis, clinical-pathological features and therapeutic challenges

Refractory celiac disease (RCD) and enteropathy-associated T-cell lymphoma (EATL) are rare, yet severe complications of celiac disease (CD). Over the last decades, several studies have addressed the biology and clinical-pathological features of such conditions, highlighting unique disease patterns and recurrent genetic events. Current classification proposals identify two forms of RCD, namely: (i) type 1 RCD (RCD-I), characterized by phenotypically normal intra-epithelial lymphocytes (IELs); and (ii) type 2 RCD (RCD-II), featuring phenotypically aberrant IELs. While RCD-I likely represents a gluten-independent dysimmune reaction against small bowel epithelial cells, RCD-II is better considered an in situ aggressive T-cell lymphoma, with high rates of progression to overt EATL. The diagnosis of RCD and EATL is often challenging, due to misleading clinical-pathological features and to significant overlap with several CD-unrelated gastro-intestinal disorders. Similarly, the treatment of RCD and EATL is an unmet clinical need for both gastroenterologists and hematologists. Moving from such premises, this review aims to provide a comprehensive view of RCD and EATL, specifically considering their pathogenesis and the many still open issues concerning their diagnosis and clinical management.

SOHO State of the Art Updates and Next Questions | Challenging Cases in Rare T-Cell Lymphomas

Mature T- and NK-cell neoplasms (MTNKN) collectively represent a rare disorder, representing less than 15% of all non-Hodgkin lymphoma (NHL) cases and qualifying for orphan disease designation by the U.S. Food and Drug Administration (FDA). These consist of 9 families in the fifth revised WHO classification of lymphoid neoplasms, which are made up of over 30 disease subtypes, underscoring the heterogeneity of clinical features, molecular biology, and genetics across this disease group. Moreover, the 5 most common subtypes (peripheral T-cell lymphoma, not otherwise specified; nodal TFH cell lymphoma, angioimmunoblastic type; extranodal NK-cell/T-cell lymphoma; adult T-cell leukemia/lymphoma; and ALK-positive or -negative anaplastic large cell lymphoma) comprise over 75% of MTNKN cases, so other subtypes are exceedingly rare in the context of all NHL diagnoses and consequently often lack consensus on best practices in diagnosis and management. In this review, we discuss the following entities-enteropathy-associated T-cell lymphoma (EATL), monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), hepatosplenic T-cell lymphoma (HSTCL), subcutaneous panniculitis-like T-cell lymphoma (SPTCL), and primary cutaneous ɣδ T-cell lymphoma (PCGD-TCL) - with an emphasis on clinical and diagnostic features and options for management.

Helicobacter pylori and Its Role in Gastric Cancer

Gastric cancer is a challenging public health concern worldwide and remains a leading cause of cancer-related mortality. The primary risk factor implicated in gastric cancer development is infection with Helicobacter pylori. H. pylori induces chronic inflammation affecting the gastric epithelium, which can lead to DNA damage and the promotion of precancerous lesions. Disease manifestations associated with H. pylori are attributed to virulence factors with multiple activities, and its capacity to subvert host immunity. One of the most significant H. pylori virulence determinants is the cagPAI gene cluster, which encodes a type IV secretion system and the CagA toxin. This secretion system allows H. pylori to inject the CagA oncoprotein into host cells, causing multiple cellular perturbations. Despite the high prevalence of H. pylori infection, only a small percentage of affected individuals develop significant clinical outcomes, while most remain asymptomatic. Therefore, understanding how H. pylori triggers carcinogenesis and its immune evasion mechanisms is critical in preventing gastric cancer and mitigating the burden of this life-threatening disease. This review aims to provide an overview of our current understanding of H. pylori infection, its association with gastric cancer and other gastric diseases, and how it subverts the host immune system to establish persistent infection.

Long-term clinical outcomes of gastric mucosa-associated lymphoid tissue lymphoma in real-world experience

This long-term, retrospective, single-center study evaluated real-world clinical outcomes of gastric mucosa-associated lymphoid tissue (MALT) lymphoma using different therapeutic modalities and analyzed factors affecting survival outcomes and long-term prognosis. We enrolled 203 patients with pathologically confirmed low-grade gastric MALT lymphoma and examined their treatment responses. Helicobacter pylori eradication was performed in all patients with H. pylori infection (HPI) and localized stage gastric MALT lymphoma. All patients underwent pre-treatment and physical evaluations, with complete blood count, biochemistry panel, and staging workup. Among 144 HPI-positive patients with stage I or II1-2 disease who underwent H. pylori eradication, 112 (77.8%) achieved complete remission (CR). All HPI-negative patients who received first-line radiotherapy achieved CR (100%), but only 22 of 27 first-line chemotherapy-treated patients achieved CR (81.5%). Lesions in the proximal upper-third or in multiple locations and an invasion depth to the submucosa or deeper were associated with poor response to eradication, and HPI negativity was significantly correlated with poor progression-free survival. HPI eradication treatment should be the first-line treatment for patients with localized stage HPI-positive gastric MALT lymphoma. The "watch-and-wait" strategy should be adopted for delayed responders. We suggest radiotherapy for patients with a localized HPI-negative status or when eradication has failed.

Cellular Origins and Pathogenesis of Gastrointestinal NK- and T-Cell Lymphoproliferative Disorders

The intestinal immune system, which must ensure appropriate immune responses to both pathogens and commensal microflora, comprises innate lymphoid cells and various T-cell subsets, including intra-epithelial lymphocytes (IELs). An example of innate lymphoid cells is natural killer cells, which may be classified into tissue-resident, CD56bright NK-cells that serve a regulatory function and more mature, circulating CD56dim NK-cells with effector cytolytic properties. CD56bright NK-cells in the gastrointestinal tract give rise to indolent NK-cell enteropathy and lymphomatoid gastropathy, as well as the aggressive extranodal NK/T cell lymphoma, the latter following activation by EBV infection and neoplastic transformation. Conventional CD4+ TCRαβ+ and CD8αβ+ TCRαβ+ T-cells are located in the lamina propria and the intraepithelial compartment of intestinal mucosa as type 'a' IELs. They are the putative cells of origin for CD4+ and CD8+ indolent T-cell lymphoproliferative disorders of the gastrointestinal tract and intestinal T-cell lymphoma, NOS. In addition to such conventional T-cells, there are non-conventional T-cells in the intra-epithelial compartment that express CD8αα and innate lymphoid cells that lack TCRs. The central feature of type 'b' IELs is the expression of CD8αα homodimers, seen in monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), which primarily arises from both CD8αα+ TCRαβ+ and CD8αα+ TCRγδ+ IELs. EATL is the other epitheliotropic T-cell lymphoma in the GI tract, a subset of which arises from the expansion and reprograming of intracytoplasmic CD3+ innate lymphoid cells, driven by IL15 and mutations of the JAK-STAT pathway.

Targeted Next-generation Sequencing Reveals a Wide Morphologic and Immunophenotypic Spectrum of Monomorphic Epitheliotropic Intestinal T-Cell Lymphoma

Primary intestinal T-cell lymphoma (PITL) is highly aggressive and includes celiac disease-related enteropathy-associated T-cell lymphoma (EATL), monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), and primary intestinal peripheral T-cell lymphoma, not otherwise specified (ITCL-NOS). MEITL is the most common PITL in Asia, comprising of monomorphic medium-sized cells typically expressing CD8, CD56, and cytotoxic granules. Occasional cases with intermediate features between MEITL and ITCL-NOS are difficult to be classified and warrant further investigation. We collected 54 surgically resected PITLs from Taiwan, with 80% presenting with bowel perforation. The overall outcome was poor with a median survival of 7 months. Based on histopathology (monomorphic vs. pleomorphic) and immunophenotype, we classified these cases into 4 groups: MEITL with typical immunophenotype (n=34), MEITL with atypical immunophenotype (n=5), pleomorphic PITL with MEITL-like immunophenotype (n=6), and ITCL-NOS (n=9). There was no EATL in our cohort. Targeted next-generation sequencing of the first 3 groups showed highly prevalent loss-of-function mutations for SETD2 (85%, 80%, and 83%, respectively) and frequent activating mutations for STAT5B (64%, 60%, and 50%, respectively) and JAK3 (38%, 20%, and 50%, respectively). In contrast, ITCL-NOS cases had less frequent mutations of SETD2 (56%) and STAT5B (11%) and rare JAK3 mutations (11%). Our results suggest that there is a wider morphologic and immunophenotypic spectrum of MEITL as currently defined in the 2017 WHO classification. MEITL with atypical immunophenotype and PITL with MEITL-like immunophenotype shared clinicopathologic and molecular features similar to MEITL but distinct from ITCL-NOS, indicating that such cases may be considered as immunophenotypic or histopathologic variants of MEITL.

MALT lymphoma of the tongue: An unusual site that may present a diagnostic challenge

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is a low-grade B cell lymphoma that can affect any organ, usually preceded by acquisition of MALT in response to antigenic stimulus provided by infections or autoimmune diseases. Most often, MALT lymphoma involves the stomach (about 35% of cases), followed by the ocular adnexal region, skin, lungs, and salivary glands, but virtually any extranodal site can be involved. MALT lymphomas are less common at sites of normal MALT tissue, such as Waldeyer ring and the ileocecal region of the gastrointestinal tract. Lymphomas involving the tongue are extremely rare and represent approximately 3% of all lymphomas involving the head and neck region. In this study, we discuss potentially challenging diagnostic aspects of MALT lymphoma involving the tongue and review and summarize the available literature about this topic.

Hematemesis as an Initial Presentation of Enteropathy-Associated T-Cell Lymphoma

Enteropathy-associated T-cell lymphoma (EATL) is a tumor of intraepithelial T-lymphocytes arising in the small intestine. Based on the genetic profile, immunohistochemistry, and histology, EATL is divided into two subtypes. EATL type I occurs in individuals with celiac disease (CD) while EATL type II is a sporadic form that occurs in individuals without CD. Intensive chemotherapy and surgery are the mainstay treatment. However, despite the currently available treatment options, the five-year survival rate is only 9%. EATL presents as abdominal pain, nausea, or slow gastrointestinal bleeding. Severe bleeding leading to hemodynamic instability is rarely known in EATL. Therefore, we present a unique case of EATL who presented with acute and severe gastrointestinal bleeding with no prior history of CD.

Haematology in the UK: A 60‐year personal perspective

The advances in understanding the pathogenesis, in the diagnosis and classification of blood diseases and in their treatment that have been achieved over the six decades from 1960 to 2020, are reviewed. Emphasis is given to the new techniques, especially in immunology and molecular biology, that have enabled this remarkable progress. The review also highlights the major contributions of UK haematologists and non‐clinical scientists to these advances.

Clinicopathological profile of gastrointestinal lymphomas in Kashmir

BACKGROUND

The histological categorization of lymphoma has been a source of controversy for many years for both clinicians and pathologists. Clinicopathologic information of gastrointestinal lymphomas in Indian subcontinent is lacking. We studied histopathological spectrum of Primary Gastrointestinal Lymphomas (PGIL) and attempted to classify the G.I. lymphomas based on the recent WHO classification in to major histological types and immunological categories.

MATERIAL AND METHODS

This study was done to evaluate the clinicopathological pattern of 100 cases with a histopathological diagnosis of primary gastrointestinal lymphoma at a tertiary care hospital. All patients of primary gastrointestinal lymphomas were included with the help of medical records over a 11-years period that is, January 2005 to December 2015.

RESULTS

The study included 100 cases (60 males, 40 females; mean age 51.43 years; age range 4.5-90 years). The disease involved stomach in 82 (82%), small intestine in 8 (8%), large bowel and rectum in 8 (8%), gall bladder in 1 (1%) and oesophagus in 1 (1%). 82 (82%) of the 100 cases were Diffuse Large B cell lymphomas; 12 (12%) were Extra Nodal Marginal Zone Lymphomas (ENMZL of MALT type) 2 (2%) IPSID 2 (2%) of Mantle cell lymphoma morphology, 1 (1%) Burkitt's and 1(1%) enteropathy associated T cell lymphoma. The commonest presenting symptom was abdominal pain. 99 (99%) of 100 tumours were classified as B-cell lymphomas immunohistochemically and majority exhibited monoclonal light chain restriction on kappa/lambda staining. In addition; Burkitt's lymphoma showed positivity for CD 10. One tumour (1%) showed positivity for T-cell markers. The data demonstrated that primary GI NHL is more common among males, mainly in their fifth decade. Abdominal pain is the most common presenting symptom, with stomach being the most commonly involved site. Diffuse large cell lymphoma is the most frequent histologic subtype, followed by extranodal marginal-zone B cell lymphoma (MALT type). H. Pylori infection was observed in cases with low grade MALT lymphomas. Striking was the observation of two cases of IPSID (a disease commonly found in Mediterranean countries) and one case of enteropathy associated T cell lymphoma.

CONCLUSION

EGD, imaging, light microscopic examination and immunohistochemical workup for B and T cell markers and staining for light chains to assist documentation of monoclonality are of precise diagnostic value in gastrointestinal lymphomas and form a part of the diagnostic workup.

Diagnostic approach to T- and NK-cell lymphoproliferative disorders in the gastrointestinal tract

Most gastrointestinal NK and T cell lymphomas are aggressive in behavior, although in recent years a subset of indolent lymphoproliferative disorders have been described, which must be distinguished from their more malignant mimics. Intestinal T-cell lymphomas may arise from intra-epithelial lymphocytes and display epitheliotropism, such as enteropathy-associated T-cell lymphoma and monomorphic epitheliotropic intestinal T-cell lymphoma. They are both aggressive in behavior but differ in their clinic-pathological features. On the other hand, intra-epithelial lymphocytes are not prominent in intestinal T-cell lymphoma, NOS, which is a diagnosis of exclusion and probably represents a heterogeneous group of entities. Indolent lymphoproliferative disorders of NK- and T-cells of both CD8 and CD4 subsets share a chronic, recurring clinical course but display differences from each other. CD8+ T-cell lymphoproliferative disorder of GI tract has a low proliferative fraction and does not progress nor undergo large cell transformation. Whilst NK-cell enteropathy runs an indolent clinical course, it may display a high proliferation fraction. On the other hand, CD4+ indolent T-cell lymphoproliferative disorder displays variable proliferation rates and may progress or transform after a number of years. In Asia and South America, it is not uncommon to see involvement of the gastrointestinal tract by EBV-associated extranodal NK/T cell lymphoma, nasal type, which must be distinguished from NK cell enteropathy and EBV-associated mucocutaneous ulcers.

Recent advances upper gastrointestinal lymphomas: molecular updates and diagnostic implications

Approximately one-third of extranodal non-Hodgkin lymphomas involve the gastrointestinal (GI) tract, with the vast majority being diagnosed in the stomach, duodenum, or proximal small intestine. A few entities, especially diffuse large B-cell lymphoma and extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue, represent the majority of cases. In addition, there are diseases specific to or characteristic of the GI tract, and any type of systemic lymphoma can present in or disseminate to these organs. The recent advances in the genetic and molecular characterisation of lymphoid neoplasms have translated into notable changes in the classification of primary GI T-cell neoplasms and the recommended diagnostic approach to aggressive B-cell tumours. In many instances, diagnoses rely on morphology and immunophenotype, but there is an increasing need to incorporate molecular genetic markers. Moreover, it is also important to take into consideration the endoscopic and clinical presentations. This review gives an update on the most recent developments in the pathology and molecular pathology of upper GI lymphoproliferative diseases.

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

T- and NK-cell lymphoproliferative disorders of the gastrointestinal (GI) tract are uncommon, but are important to recognise as there may be morphological and immunophenotypic overlap between lymphoid lesions with vastly different clinical outcomes. Recent data have led to the reclassification of some lymphomas and inclusion of new entities in the 2016 revision of World Health Organization (WHO) classification of lymphoid neoplasms. It has become clear that enteropathy associated T-cell lymphoma (EATL), formerly thought to be composed of two subtypes known as type I and type II, are distinct entities. Type I EATL is now simply classified as EATL; it is strongly associated with coeliac disease and occurs mainly in Western populations. Type II EATL has been renamed monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL); it shows no definite association with coeliac disease and occurs worldwide with a predominance in Asian populations. There is also a group of aggressive intestinal T-cell lymphomas which do not meet criteria for EATL, MEITL, extranodal NK/T-cell lymphoma of nasal type or anaplastic large cell lymphoma. These neoplasms are now designated intestinal T-cell lymphoma, not otherwise specified. Indolent T-cell lymphoproliferative disorder of the GI tract has been included as a provisional entity in the most recent WHO classification. It is a clonal T-cell lymphoproliferative disorder (CD4+ or CD8+) with an indolent clinical course. Finally, benign NK-cell proliferations of the GI tract, variably designated 'NK-cell enteropathy' and 'lymphomatoid gastropathy' have also been recognised in the last two decades but have not been included in the WHO classification as their neoplastic nature is not established. This review covers the aforementioned lymphoid proliferations, emphasising their salient clinicopathological features and genetic abnormalities. It also provides practical insights into resolving difficult differential diagnoses in daily surgical pathology practice.

Association Between Gastric Lymphoid Follicles (Precursor Of MALT Lymphomas) And H. pylori Infection At A Referral Hospital In Iran

Purpose

Mucosa-associated lymphoid tissue (MALT) is the most common endoscopic finding in Helicobacter pylori positive patients that can progress to MALT lymphoma after a prolonged antigenic contact. This study was aimed to evaluate the prevalence of lymphoid follicles and aggregates (precursors of MALT lymphomas) in gastric mucosal biopsies and their correlation with H. pylori infection.

Patients and methods

In this study, 100 patients who had undergone an upper gastrointestinal endoscopy were enrolled. Five biopsy specimens were taken each patient through screening endoscopy and histopathological changes were evaluated and graded using the Wotherspoon System. The clinical background and H. pylori infection status were also investigated.

Results

Among the 100 cases in our series, 79 patients (79%) showed evidence of MALT in at least one biopsy specimen taken from the stomach and 21 cases (21%) had no evidence of MALT. H. pylori infection was detected in 74 (74%) patients. Lymphoid follicles were detected more frequently in H. pylori-positive patients (59%) compared to H. pylori-negative cases (3%) (P<0.001).

Conclusion

The frequency of lymphoid follicles and aggregates in gastric mucosal is associated with H. pylori infection. Further community-based studies in larger sample sizes using a combination of microscopic methods and PCR assay are required for effective monitoring of H. pylori infection.

Inference from the analysis of genetic structure of Helicobacter pylori strains isolates from two paediatric patients with recurrent infection

Background

Helicobacter pylori recurrence after successful eradication is an important problem. Children are particularly vulnerable to reinfection, by intrafamilial transmission which facilitates the acquisition or recombination of new genetic information by this bacterium. We investigated the evolutionary dynamics of 80 H. pylori strains isolated from two paediatric patients with recurrent infection (recrudescence and reinfection).

Results

We characterized the virulence genes vacA (s1, m1, s2, and m2), cagA, cagE, and babA2 and performed multilocus sequence typing (MLST) on 7 housekeeping genes (atpA, efp, ureI, ppa, mutY, trpC, and yphC) to infer the evolutionary dynamics of the H. pylori strains through phylogenetic and genealogic inference analyses, genetic diversity analysis and the exploration of recombination events during recurrent infections. The virulence genotype vacAs1m1/cagA+/cagE+/babA2 was present at a high frequency, as were the EPIYA motifs EPIYA-A, −B and -C. Furthermore, the housekeeping genes of the H. pylori strains exhibited high genetic variation, comprising 26 new alleles and 17 new Sequence Type (ST). In addition, the hpEurope (76.5%) and hspWAfrica (23.5%) populations predominated among the paediatric strains. All strains, regardless of their ancestral affiliation, harboured western EPIYA motifs.

Conclusions

This study provides evidence of the evolutionary dynamics of the H. pylori strains in two paediatric patients during recrudescence and reinfection events. In particular, our study shows that the strains changed during these events, as evidenced by the presence of different STs that emerged before and after treatment; these changes may be due to the accumulation of mutations and recombination events during the diversification process and recolonization of the patients by different genotypes.

Electronic supplementary material

The online version of this article (10.1186/s12866-019-1554-z) contains supplementary material, which is available to authorized users.

Novel Insights of Lymphomagenesis of Helicobacter pylori-Dependent Gastric Mucosa-Associated Lymphoid Tissue Lymphoma

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is the most common subtype of gastric lymphoma. Most gastric MALT lymphomas are characterized by their association with the Helicobacter pylori (HP) infection and are cured by first-line HP eradication therapy (HPE). Several studies have been conducted to investigate why most gastric MALT lymphomas remain localized, are dependent on HP infection, and show HP-specific intratumoral T-cells (e.g., CD40-mediated signaling, T-helper-2 (Th2)-type cytokines, chemokines, costimulatory molecules, and FOXP3+ regulatory T-cells) and their communication with B-cells. Furthermore, the reason why the antigen stimuli of these intratumoral T-cells with tonic B-cell receptor signaling promote lymphomagenesis of gastric MALT lymphoma has also been investigated. In addition to the aforementioned mechanisms, it has been demonstrated that the translocated HP cytotoxin-associated gene A (CagA) can promote B-cell proliferation through the activation of Src homology-2 domain-containing phosphatase (SHP-2) phosphorylation-dependent signaling, extracellular-signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK), B-cell lymphoma (Bcl)-2, and Bcl-xL. Furthermore, the expression of CagA and these CagA-signaling molecules is closely associated with the HP-dependence of gastric MALT lymphomas (completely respond to first-line HPE). In this article, we summarize evidence of the classical theory of HP-reactive T-cells and the new paradigm of direct interaction between HP and B-cells that contributes to the HP-dependent lymphomagenesis of gastric MALT lymphomas. Although the role of first-line HPE in the treatment of HP-negative gastric MALT lymphoma remains uncertain, several case series suggest that a proportion of HP-negative gastric MALT lymphomas remains antibiotic-responsive and is cured by HPE. Considering the complicated interaction between microbiomes and the genome/epigenome, further studies on the precise mechanisms of HP- and other bacteria-directed lymphomagenesis in antibiotic-responsive gastric MALT lymphomas are warranted.

Rare T-Cell Subtypes

There are a number of rare T-cell lymphoma subtypes that may be encountered in clinical practice. In recent years, improved immunohistochemical techniques and molecular tumor profiling have permitted refinement of some of the diagnostic categories in this group, as well as the recognition of distinct conditions not previously well elucidated. In this chapter, we cover the diagnostic and clinical features of some of the more common of these conditions, including subcutaneous panniculitis-like T-cell lymphoma, cutaneous gamma-delta T-cell lymphoma, enteropathy-associated T-cell lymphoma, monomorphic epitheliotropic intestinal T-cell lymphoma, primary cutaneous CD8-positive aggressive epidermotropic cytotoxic T-cell lymphoma, CD4-positive small/medium T-cell lymphoproliferative disorder, and acral CD8-positive T-cell lymphoma. Given the rarity of these conditions, optimal treatments approaches are not always well established, not least as data from large-scale clinical trials are lacking. In this chapter, we aim to provide a summation of current thinking around best treatment, as well as highlighting some controversies in the management of these diagnoses.

Gastric MALT lymphoma and Helicobacter pylori

Marginal zone lymphomas of the MALT type are a type of B-cell neoplasms that involve extranodal tissues and have an indolent clinical behaviour. The stomach is the most common site and most patients are infected by Helicobacter pylori. An increase in the resistance of this bacterium to several antibiotics has been observed in the last years and this fact has determined the review of treatment guidelines. In areas with resistance to clarithromycin greater than 15%, classical triple therapy should be abandoned and quadruple regimens with or without bismuth are currently recommended. Thus, these new guidelines for eradication treatment should be applied to patients with gastric MALT lymphoma associated with H. pylori infection.

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.

First-line antibiotic therapy in Helicobacter pylori-negative low-grade gastric mucosa-associated lymphoid tissue lymphoma

First-line antibiotic treatment for eradicating Helicobacter pylori (HP) infection is effective in HP-positive low-grade gastric mucosa-associated lymphoid tissue lymphoma (MALToma), but its role in HP-negative cases is uncertain. In this exploratory retrospective study, we assessed the outcome and potential predictive biomarkers for 25 patients with HP-negative localized gastric MALToma who received first-line HP eradication (HPE) therapy. An HP-negative status was defined as negative results on histology, rapid urease test, ¹³C urea breath test, and serology. We observed an antibiotic response (complete remission [CR], number = 8; partial remission, number = 1) in 9 (36.0%) out of 25 patients. A t(11;18)(q21;q21) translocation was detected in 7 (43.8%) of 16 antibiotic-unresponsive cases, but in none of the 9 antibiotic-responsive cases (P = 0.027). Nuclear BCL10 expression was significantly higher in antibiotic-unresponsive tumors than in antibiotic-responsive tumors (14/16 [87.5%] vs. 1/9 [11.1%]; P = 0.001). Nuclear NF-κB expression was also significantly higher in antibiotic-unresponsive tumors than in antibiotic-responsive tumors (12/16 [75.0%] vs. 1/9 [11.1%]; P = 0.004). A substantial portion of patients with HP-negative gastric MALToma responded to first-line HPE. In addition to t(11;18)(q21;q21), BCL10 and NF-κB are useful immunohistochemical biomarkers to predict antibiotic-unresponsive status in this group of tumors.

Clinicopathologic Spectrum of Gastrointestinal T-cell Lymphoma: Reappraisal Based on T-cell Receptor Immunophenotypes

The differential diagnosis of primary gastrointestinal EBV T-cell lymphoma (GITCL) includes enteropathy-associated T-cell lymphoma (EATL), peripheral T-cell lymphoma, not otherwise specified, adult T-cell leukemia/lymphoma, and anaplastic large cell lymphoma. Type II EATL is considered to be a tumor of intraepithelial lymphocytes. However, the evaluation of intraepithelial lymphocytosis by biopsy specimens is challenging, which poses a diagnostic problem between the EATL and peripheral T-cell lymphoma, not otherwise specified. This situation requested us to establish a pragmatic diagnostic approach for the classification of GITCL. We identified 42 cases of GITCL and analyzed clinicopathologic features, especially addressing their T-cell receptor (TCR) phenotype. Nine (21%) of 42 GITCL cases were positive for TCRγ protein expression. Among these TCRγ cases, TCRβ expression or not was detected in 5 and 4, respectively, but resulted in no further clinicopathologic differences. TCRβ positivity without TCRγ expression (βγ) was seen in 9 GITCL patients (21%). Twenty-four patients (57%) were negative for TCRβ and γ expression (βγ). Compared with TCRβγ or βγ type, TCRγ cases were characterized by exclusive involvement of intestinal sites (100% vs. 11%, P<0.001; 100% vs. 58%, P=0.032, respectively), but not of stomach (0% vs. 78%, P=0.002; 0% vs. 38%, P=0.039, respectively). Notably, TCRγ positivity was an independent unfavorable prognostic factor among our GITCL patients (P<0.001). Considering our results, TCRγ GITCL, that is, intestinal γδ T-cell lymphoma, appears to constitute a distinct disease entity.

The B-cell-activating factor signalling pathway is associated with Helicobacter pylori independence in gastric mucosa-associated lymphoid tissue lymphoma without t(11;18)(q21;q21)

We previously reported that activation of the B-cell-activating factor (BAFF) pathway upregulates nuclear factor-κB (NF-κB) and induces BCL3 and BCL10 nuclear translocation in Helicobacter pylori (HP)-independent gastric diffuse large B-cell lymphoma (DLBCL) tumours with evidence of mucosa-associated lymphoid tissue (MALT). However, the significance of BAFF expression in HP independence of gastric low-grade MALT lymphomas without t(11;18)(q21;q21) remains unexplored. Sixty-four patients who underwent successful HP eradication for localized HP-positive gastric MALT lymphomas without t(11;18)(q21;q21) were studied. BAFF expression was significantly higher in the HP-independent group than in the HP-dependent group [22/26 (84.6%) versus 8/38 (21.1%); p < 0.001]. Similarly, BAFF receptor (BAFF-R) expression (p = 0.004) and nuclear BCL3 (p = 0.004), BCL10 (p < 0.001), NF-κB (p65) (p = 0.001) and NF-κB (p52) (p = 0.005) expression were closely correlated with the HP independence of these tumours. Moreover, BAFF overexpression was significantly associated with BAFF-R expression and nuclear BCL3, BCL10, NF-κB (p65) and NF-κB (p52) expression. These findings were further validated in an independent cohort, including 40 HP-dependent cases and 18 HP-independent cases of gastric MALT lymphoma without t(11;18)(q21;q21). The biological significance of BAFF signalling in t(11;18)(q21;q21)-negative lymphoma cells was further studied in two types of lymphoma B cell: OCI-Ly3 [non-germinal centre B-cell origin DLBCL without t(11;18)(q21;q21) cell line] and MA-1 [t(14;18)(q32;q21)/IGH-MALT1-positive DLBCL cell line]. In both cell lines, we found that BAFF activated the canonical NF-κB and AKT pathways, and induced the formation of BCL10-BCL3 complexes, which translocated to the nucleus. BCL10 and BCL3 nuclear translocation and NF-κB (p65) transactivation were inhibited by either LY294002 or by silencing BCL3 or BCL10 with small interfering RNA. BAFF also activated non-canonical NF-κB pathways (p52) through tumour necrosis factor receptor-associated factor 3 degradation, NF-κB-inducing kinase accumulation, inhibitor of κB kinase (IKK) α/β phosphorylation and NF-κB p100 processing in both cell lines. Our data indicate that the autocrine BAFF signal transduction pathway contributes to HP independence in gastric MALT lymphomas without the t(11;18)(q21;q21) translocation. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Expressions of the CagA protein and CagA-signaling molecules predict Helicobacter pylori dependence of early-stage gastric DLBCL

Expression of CagA and CagA-signaling molecules p-SHP2 and p-ERK is associated with HP dependence of gastric DLBCL. CagA is associated with the direct lymphomagenic effect of HP on B cells of HP-dependent gastric DLBCL.

B-cell Non-Hodgkin Lymphomas with Plasmacytic Differentiation

B-cell non-Hodgkin lymphomas with plasmacytic differentiation are a diverse group of entities with extremely variable morphologic features. Diagnostic challenges can arise in differentiating lymphoplasmacytic lymphoma from marginal zone lymphoma and other low-grade B-cell lymphomas. In addition, plasmablastic lymphomas can be difficult to distinguish from diffuse large B-cell lymphoma or other high-grade lymphomas. Judicious use of immunohistochemical studies and molecular testing can assist in appropriate classification.

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.

High Expression of Intestinal Homing Receptor CD103 in Adult T-Cell Leukemia/Lymphoma, Similar to 2 Other CD8+ T-Cell Lymphomas

We investigated the expression of the αEβ7 integrin (CD103)-intestinal homing receptor of T-intraepithelial lymphocytes (IELs) in 130 cases of adult T-cell leukemia/lymphoma (ATLL). We detected CD103 lymphoma cells in 55% (31/56) of mainly gastrointestinal (GI)-involved ATLL cases. Among them, lymphoma cells of 18 cases located in other involved organs had similar CD103 expression patterns. Histologically, we found (a) increased reactive IELs in non-neoplastic mucosal layers in 28% (5/18) of surgical and mucosal resection cases, (b) preserved epithelial glands, and (c) numerous small intraepithelial ATLL nests in involved lesions in 36 (69%) and 21 (40%), respectively, of the 52 examined cases. These 3 patterns were common in intestinal type II enteropathy-associated T-cell lymphoma but were rare in intestinal EBV nasal-type/like T/natural killer (NK)-cell lymphoma. We detected CD103 tumor cells in 41% (16/39) of lymph node-involved ATLL, in 31% (11/35) of skin-involved ATLL, in 68% (21/31) of type II CD4 enteropathy-associated T-cell lymphoma cases, in 36% (8/22) of primary gastric T/NK-cell lymphomas, and in 77% (7/9) of CD8 epidermotropic mycosis fungoides. CD103 ATLL prefers involving the GI tract over the skin (P<0.05). CD103 expression in GI-involved and/or total ATLL cases was significantly higher than in other 9 T/NK-cell lymphoma groups (P<0.05 or 0.01). Only ATLL cases were commonly CD103 in CD4 T/NK-cell lymphoma groups (P<0.05 or 0.01). Human T-lymphotropic virus-1-infected CD103 T-IELs and mucosal T cells may be important sources of ATLL.

Male Syrian Hamsters Experimentally Infected with Helicobacter spp. of the H. bilis Cluster Develop MALT-Associated Gastrointestinal Lymphomas

BACKGROUND

Aged hamsters naturally infected with novel Helicobacter spp. classified in the H. bilis cluster develop hepatobiliary lesions and typhlocolitis.

METHODS

To determine whether enterohepatic H. spp. contribute to disease, Helicobacter-free hamsters were experimentally infected with H. spp. after suppression of intestinal bacteria by tetracycline treatment of dams and pups. After antibiotic withdrawal, weanlings were gavaged with four H. bilis-like Helicobacter spp. isolated from hamsters or H. bilis ATCC 43879 isolated from human feces and compared to controls (n = 7 per group).

RESULTS

Helicobacter bilis 43879-dosed hamsters were necropsied at 33 weeks postinfection (WPI) due to the lack of detectable infection by fecal PCR; at necropsy, 5 of 7 were weakly PCR positive but lacked intestinal lesions. The remaining hamsters were maintained for ~95 WPI; chronic H. spp. infection in hamsters (6/7) was confirmed by PCR, bacterial culture, fluorescent in situ hybridization, and ELISA. Hamsters had mild-to-moderate typhlitis, and three of the male H. spp.-infected hamsters developed small intestinal lymphoma, in contrast to one control. Of the three lymphomas in H. spp.-infected hamsters, one was a focal ileal mucosa-associated lymphoid tissue (MALT) B-cell lymphoma, while the other two were multicentric small intestinal large B-cell lymphomas involving both the MALT and extra-MALT mucosal sites with lymphoepithelial lesions. The lymphoma in the control hamster was a diffuse small intestinal lymphoma with a mixed population of T and B cells.

CONCLUSIONS

Results suggest persistent H. spp. infection may augment risk for gastrointestinal MALT origin lymphomas. This model is consistent with H. pylori/heilmannii-associated MALT lymphoma in humans and could be further utilized to investigate the mechanisms of intestinal lymphoma development.

Recent advances in intestinal lymphomas

A large variety of lymphoma types may develop as primary intestinal neoplasms in the small intestines or, less often, in the colorectum. Among these are a few entities such as enteropathy-associated T-cell lymphoma or immunoproliferative small intestinal disease that, essentially, do not arise elsewhere than in the gastrointestinal tract. In most instances the primary intestinal lymphomas belong to entities that also occur in lymph nodes or other mucosal sites, and may show some peculiar features. In the case of follicular lymphoma, important differences exist between the classical nodal cases and the intestinal cases, considered as a variant of the disease. It is likely that the local intestinal mucosal microenvironment is a determinant in influencing the pathobiological features of the disease. In this review we will present an update on the clinical, pathological and molecular features of the lymphoid neoplasms that most commonly involve the intestines, incorporating recent developments with respect to their pathobiology and classification. We will emphasize and discuss the major differential diagnostic problems encountered in practice, including the benign reactive or atypical lymphoid hyperplasias, indolent lymphoproliferative disorders of T or natural killer (NK) cells, and Epstein-Barr virus (EBV)-related lymphoproliferations.

Detection of monoclonality in intestinal lymphoma with polymerase chain reaction for antigen receptor gene rearrangement analysis to differentiate from enteritis in dogs

The diagnosis of canine intestinal lymphoma by morphological examination is challenging, especially when endoscopic tissue specimens are used. The utility of detection of antigen receptor gene rearrangement by polymerase chain reaction (PARR) in canine lymphoma has been well established, but its usefulness to distinguish enteritis and intestinal lymphoma remains unclear. In this retrospective study we assessed clonality of 29 primary canine intestinal lymphoma, 14 enteritis and 15 healthy control cases by PARR analysis, using formalin-fixed, paraffin-embedded full-thickness tissue specimens. We could detect monoclonal rearrangements in 22 of 29 canine intestinal lymphomas [76%; 95% confidence interval (CI) 56-90%] and polyclonal rearrangements in all of the enteritis and healthy control cases (100%; CI 88-100%). We revealed a predominance of T-cell phenotype compared to B-cell phenotype (85%; CI 65-96% and 15%; CI 4-35%, respectively). We showed that PARR analysis contributes to differentiation of canine intestinal lymphoma from enteritis and to phenotyping of lymphomas.

A rare but potentially fatal cause of diarrhoea and weight loss: enteropathy-associated T-cell lymphoma

Enteropathy-associated T-cell lymphoma (EATL) is a rare but potentially fatal cause of diarrhoea and weight loss. EATL commonly presents with abdominal pain, diarrhoea and weight loss, but can also present with complications such as bowel obstruction and perforation. It is a tumour of intraepithelial lymphocytes that occurs in a relatively young population. It is the most common neoplastic complication of coeliac disease, but can occur with no prior diagnosis of coeliac disease. This case demonstrates the difficulties that can be faced in diagnosing this disorder, particularly when there is no preceding history of coeliac disease. Early diagnosis is of utmost importance in order to start treatment before the effects of malnutrition increase the risk of complications from chemotherapy. Hence awareness of the condition among general medical physicians, to whom it will often present first, is essential. However, even with prompt diagnosis, outcomes for this condition remain poor.

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.

Population genetic analyses of Helicobacter pylori isolates from Gambian adults and children

The gastric pathogen Helicobacter pylori is one of the most genetically diverse of bacterial species. Much of its diversity stems from frequent mutation and recombination, preferential transmission within families and local communities, and selection during persistent gastric mucosal infection. MLST of seven housekeeping genes had identified multiple distinct H. pylori populations, including three from Africa: hpNEAfrica, hpAfrica1 and hpAfrica2, which consists of three subpopulations (hspWAfrica, hspCAfrica and hspSAfrica). Most detailed H. pylori population analyses have used strains from non-African countries, despite Africa's high importance in the emergence and evolution of humans and their pathogens. Our concatenated sequences from seven H. pylori housekeeping genes from 44 Gambian patients (MLST) identified 42 distinct sequence types (or haplotypes), and no clustering with age or disease. STRUCTURE analysis of the sequence data indicated that Gambian H. pylori strains belong to the hspWAfrica subpopulation of hpAfrica1, in accord with Gambia's West African location. Despite Gambia's history of invasion and colonisation by Europeans and North Africans during the last millennium, no traces of Ancestral Europe1 (AE1) population carried by those people were found. Instead, admixture of 17% from Ancestral Europe2 (AE2) was detected in Gambian strains; this population predominates in Nilo-Saharan speakers of North-East Africa, and might have been derived from admixture of hpNEAfrica strains these people carried when they migrated across the Sahara during the Holocene humid period 6,000–9,000 years ago. Alternatively, shared AE2 ancestry might have resulted from shared ancestral polymorphisms already present in the common ancestor of sister populations hpAfrica1 and hpNEAfrica.

Helicobacter pylori-related diffuse large B-cell lymphoma of the stomach: a distinct entity with lower aggressiveness and higher chemosensitivity

We recently showed that Helicobacter pylori (HP)-positive gastric ‘pure' diffuse large B-cell lymphoma (DLBCL) may respond to HP eradication therapy. However, whether these HP-related ‘pure' DLBCL of the stomach may differ fundamentally from those unrelated to HP remains unclear. In this study, we compared the clinicopathologic features of these two groups of patients who had been uniformly treated by conventional chemotherapy. Forty-six patients were designated HP-positive and 49 were HP-negative by conventional criteria. HP-positive patients had a lower International Prognostic Index score (0–1, 65% vs 43%, P=0.029), a lower clinical stage (I-IIE1, 70% vs 39%, P=0.003), a better tumor response to chemotherapy (complete pathologic response, 76% vs 47%, P=0.004) and significantly superior 5-year event-free survival (EFS) (71.7% vs 31.8%, P<0.001) and overall survival (OS) (76.1% vs 39.8%, P<0.001). To draw a closer biologic link with HP, HP-positive tumors were further examined for CagA expression in lymphoma cells. Compared with CagA-negative cases (n=16), CagA-positive cases (n=27) were associated with high phosphorylated SHP-2 expression (P=0.016), and even better 5-year EFS (85.2% vs 46.3%, P=0.002) and OS (88.9% vs 52.9%, P=0.003). HP-related gastric ‘pure' DLBCL may be a distinct tumor entity, which is less aggressive, and responds better to conventional chemotherapy.

The recognition and classification of lymphoproliferative disorders of the gut

Gastrointestinal lymphomas can be difficult to diagnose, particularly in small samples, when early in development, or when of unusual types. In this review, we describe lymphoid proliferations in the gastrointestinal tract in a location-based manner, including, mouth, esophagus, stomach, small intestine, and large bowel. For the purpose of differential diagnosis, benign mimics of lymphoma are also described. Lymphoma types that are specifically addressed include plasmablastic, extranodal natural killer/T-cell-nasal type, extranodal marginal zone lymphoma (eg, mucosa-associated lymphoid tissue lymphoma), diffuse large B cell, primary follicular of small intestine, enteropathy-associated T cell, and Burkitt and mantle cell. Immunohistochemical markers useful in the diagnostic approach are elaborated in detail.

Prognostic characteristics of gastrointestinal tract NK/T-cell lymphoma: an analysis of 47 patients in China

BACKGROUND

The gastrointestinal tract is the most common primary site of extranodal lymphomas, whereas gastrointestinal natural killer/T-cell (GINKT) lymphomas are relatively rare. To date, neither the prognostic characteristics nor the clinical features or optimal therapeutic approach for GINKT has yet been defined.

PATIENTS AND METHODS

In this study, a retrospective analysis was carried out on clinical data obtained from 47 patients diagnosed with GINKT lymphoma between May 1999 and August 2011 at West China Hospital.

RESULTS

Patients had a median age of 37 years. Thirty-five of the patients were men (74.5%). The common clinical manifestations included fever (78.7%) and abdominal pain (76.6%). Seventeen patients had intestinal perforation (36.2%). All patients showed ulcerative lesions; the most common site of involvement was the colon (27/47; 57.4%), followed by the jejunoileum and ileocecum (14/47; 29.8%). The median survival period was 2.83 (95% confidence interval, 0.27-29) months. Age, perforation, B syndrome, staging according to Lugano system, and surgery were independent prognostic risk factors for GINKT lymphoma.

CONCLUSIONS

This study concluded that GINKT lymphoma is prone to perforation, hemorrhage, and other complications; moreover, the prognosis is very poor. The Lugano staging is a relatively suitable staging system. Surgery before perforation is a key therapy factor that affected prognosis. Although the roles played by chemotherapy and radiotherapy are unclear, combination therapy is necessary.

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.

Detection of the Helicobacter pylori CagA protein in gastric mucosa-associated lymphoid tissue lymphoma cells: clinical and biological significance

We previously reported that CagA can be translocated into B cells in Helicobacter pylori (HP) coculture media, and the translocation appears biologically significant as activation of the relevant cellular pathways was noticed. In this study, we further explore if CagA can be detected in malignant B cells of HP-positive gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Expression of CagA was evaluated by immunohistochemistry. CagA expression was further confirmed by western blot analysis. The association between CagA expression in malignant B cells and tumor response to HP eradication therapy (HPE) was evaluated in 64 stage IE gastric MALT lymphoma patients. We detected CagA expression in 31 (48.4%) of 64 patients: 26 (68.4%) of the 38 HP-dependent cases and 5 (19.2%) of the 26 HP-independent cases (P<0.001). Patients with CagA expression responded to HPE quicker than those without (median time to complete remission, 3.0 vs 6.5 months, P=0.025). Our results indicated that CagA can be translocated into malignant B cells of MALT lymphoma, and the translocation is clinically and biologically significant.

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.

Helicobacter pylori and mucosa-associated lymphoid tissue: what's new

Low-grade mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach, gastric MALT lymphoma, is associated with Helicobacter pylori infection. The eradication of H pylori using antibiotics is successful in 60% to 80% of affected patients. In contrast to the previous paradigm, we and other investigators have shown that a certain proportion of patients with H pylori-positive early-stage diffuse large B-cell lymphoma (DLBCL) of the stomach with histological evidence of MALT lymphoma, including high-grade transformed gastric MALT lymphoma and gastric DLBCL(MALT), achieved long-term complete pathological remission (pCR) after first-line H pylori eradication therapy, indicating that the loss of H pylori dependence and high-grade transformation are separate events in the progression of gastric lymphoma. In addition, patients with H pylori-positive gastric DLBCL without histological evidence of MALT (gastric pure DLBCL) may also respond to H pylori eradication therapy. A long-term follow-up study showed that patients who achieved pCR remained lymphoma free. Gastric MALT lymphoma is indirectly influenced by H pylori infection through T-cell stimulation, and recent studies have shown that H pylori-triggering chemokines and their receptors, H pylori-associated epigenetic changes, H pylori-regulated miRNA expression, and tumor infiltration by CD4+CD25+ regulatory T cells contribute to lymphomagenesis of gastric MALT lymphoma. Recent studies have also demonstrated that the translocation of CagA into B lymphocytes inhibits apoptosis through p53 accumulation, BAD phosphorylation, and the up-regulation of Bcl-2 and Bcl-XL expression. In gastric MALT lymphoma, CagA may stimulate lymphomagenesis directly, through the regulation of signal transduction, and intracellular CagA is associated with H pylori dependence. These findings represent a substantial paradigm shift compared with the classical theory of H pylori-reactive T cells contributing indirectly to the development of MALT lymphoma. In conclusion, a wide range of H pylori-related gastric lymphomas have been identified. The use of antibiotics as the sole first-line therapy for early-stage gastric pure DLBCL requires validation in a prospective study. The clinical and biological significance of the CagA oncoprotein in the lymphomagenesis of gastric MALT lymphoma warrants further study.