Low-grade gastric B-cell lymphoma of mucosa-associated lymphoid tissue (MALT): a multifocal disease

Carcinogenic mechanisms of virus-associated lymphoma

The development of lymphoma is a complex multistep process that integrates numerous experimental findings and clinical data that have not yet yielded a definitive explanation. Studies of oncogenic viruses can help to deepen insight into the pathogenesis of lymphoma, and identifying associations between lymphoma and viruses that are established and unidentified should lead to cellular and pharmacologically targeted antiviral strategies for treating malignant lymphoma. This review focuses on the pathogenesis of lymphomas associated with hepatitis B and C, Epstein-Barr, and human immunodeficiency viruses as well as Kaposi sarcoma-associated herpesvirus to clarify the current status of basic information and recent advances in the development of virus-associated lymphomas.

Hepatitis C Virus (HCV)-Ribonucleic Acid (RNA) As a Biomarker for Lymphoid Malignancy with HCV Infection

The hepatitis C virus (HCV) is potentially associated with liver cancer, and advances in various drugs have led to progress in the treatment of hepatitis C and attempts to prevent its transition to liver cancer. Furthermore, reactivation of HCV has been observed in the treatment of lymphoma, during which the immortalization and proliferation of lymphocytes occur, which leads to the possibility of further stimulating cytokines and the like and possibly to the development of lymphoid malignancy. There are also cases in which the disappearance of lymphoid malignancy has been observed by treating HCV and suppressing HCV-Ribonucleic acid (RNA), as well as cases of recurrence with an increase in HCV-RNA. While HCV-associated lymphoma has a poor prognosis, improving the prognosis with Direct Acting Antivirals (DAA) has recently been reported. The reduction and eradication of HCV-RNA by means of DAA is thus important for the treatment of lymphoid malignancy associated with HCV infection, and HCV-RNA can presumably play a role as a biomarker. This review provides an overview of what is currently known about HCV-associated lymphoma, its epidemiology, the mechanisms underlying the progression to lymphoma, its treatment, the potential and limits of HCV-RNA as a therapeutic biomarker, and biomarkers that are expected now that DAA therapy has been developed.

Long-Term Clinical Outcome and Predictive Factors for Relapse after Radiation Therapy in 145 Patients with Stage I Gastric B-Cell Lymphoma of Mucosa-Associated Lymphoid Tissue Type

Simple Summary

Helicobacter pylori-associated gastric low-grade B-cell lymphoma of mucosa-associated lymphoid tissue type (MALT lymphoma) constitutes >80% of gastric MALT lymphoma. Eradication therapy has been accepted as a standard approach for initial treatment. However, in patients who present without evidence of infection or who fail to respond to eradication therapy, a solid consensus for treatment is not available. Furthermore, few studies have evaluated the predictive factors for response or relapse after radiation therapy (RT) as heterogeneous, relatively small study populations have been treated with RT, and only a small number of events have been reported after treatment. In this study, we report the long-term clinical outcome of stage I gastric MALT lymphoma treated with RT. We also identified that the tumor’s dominant location in the stomach is a predictive factor for relapse after RT.

Abstract

This study aimed to evaluate the clinical outcomes of radiation therapy (RT) for stage I gastric mucosa-associated lymphoid tissue (MALT) lymphoma and find predictive factors for relapse after RT. This retrospective study included 145 patients without a prior history of treatment, except Helicobacter pylori eradication therapy, who were irradiated for stage I gastric MALT lymphoma. The gastric body was the most commonly involved location of the dominant lesion (66.9%), and H. pylori infection at first diagnosis was detected in 61 (42.1%) patients. The median RT dose was 30 Gy (range, 24–40). Seven patients had an autoimmune disease. All patients except one achieved a complete remission at post-treatment endoscopic biopsy after a median of 2 months (range, 1–36). During the median follow-up at 51 months (range, 2–146), 11 patients experienced relapses: in the stomach (n = 5), in a distant site (n = 4), and in both (n = 2). The five-year overall, local relapse-free, distant relapse-free, and relapse-free survival (RFS) rates were 98.6%, 94.0%, 97.1%, and 92.3%, respectively. In multivariate analysis for RFS, the location of MALT lymphoma other than in the gastric body was significantly associated with an increased risk of relapse (hazard ratio 5.85 (95% CI 1.49–22.9), p = 0.011). RT results in favorable clinical outcomes in patients with stage I gastric MALT lymphoma. Tumor location could be a predictive factor for relapse after RT.

Hepatitis C virus-associated non-Hodgkin lymphomas: the endless history

Hepatitis C virus (HCV) is a global population problem due to its high prevalence worldwide. In the prognosis of patients with HCV not only hepatic but increasingly frequent of extrahepatic HCV manifestations, such as mixed cryoglobulinemia (MC) and non-Hodgkin's lymphoma (NHL), are important. The role of the HCV virus in the pathogenesis of lymphoproliferative diseases is confirmed by a large number of epidemiological studies, as well as by the effectiveness of antiviral therapy in patients with non-Hodgkin's lymphoma (NHL). The purpose of the review was to provide an overview of epidemiological and biological data explaining the role of HCV in the development of NHL. The review also discusses HCV-associated NHL treatment by the traditional antiviral therapy (interferon and ribavirin) and by the new direct antiviral agents.

[Diagnosis and Treatment of Gastric Mucosa-associated Lymphoid Tissue Lymphoma]

The stomach is the most common primary site of an extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) type, which is characterized by an indolent clinical course. A diagnosis of gastric MALT lymphoma requires an endoscopic biopsy that should be confirmed by an experienced pathologist. Gastric MALT lymphoma shows a variable endoscopic appearance, including erosion, erythema, discoloration, atrophy, ulcer, and subepithelial lesion. The distribution is often multifocal. Therefore, clinical suspicion and multiple biopsies are essential for an accurate diagnosis. Gastric MALT lymphoma is almost invariably associated with a Helicobacter pylori (H. pylori) infection. H. pylori eradication therapy is the mainstay of treatment, which must be delivered to all patients regardless of the H. pylori infection status or stage. For patients who have failed to achieve remission following eradication therapy, radiotherapy or chemotherapy can be considered. Radiotherapy is an effective treatment modality for a localized stage and shows excellent outcomes. In the presence of disseminated or advanced disease, chemotherapy and/or immunotherapy with the anti-CD20 monoclonal antibody, rituximab, can be applied. Treatment should be individualized according to the stage and symptoms, as well as the patients' preference. Given that the clinical course of gastric MALT lymphoma is usually indolent, watchful waiting may be an adequate strategy in selected cases where scheduled follow-up is guaranteed.

Association of the Helicobacter pylori cagA, vacA, and iceA genotypes with chronic follicular gastritis in a Colombian population at high risk for gastric cancer

INTRODUCTION AND OBJECTIVE

Follicular gastritis is associated with Helicobacter pylori infection, but little is known of its relation to bacterial genotypes. Our aim was to establish the relation between follicular gastritis and different H. pylori strains.

MATERIALS AND METHODS

An analytic case-control study was conducted that included 36 patients with follicular gastritis (cases) and 83 with nonatrophic gastritis (controls). The sociodemographic information was obtained through a questionnaire. Biopsies were evaluated according to the Sydney System and the Wotherspoon scoring system. Helicobacter pylori genotyping was performed using the polymerase chain reaction technique. The quantitative variables were presented as mean and standard deviation and the qualitative variables as proportions and absolute frequency. The effect of each variable on outcome (follicular gastritis) was evaluated through the odds ratio and its 95% confidence interval. Statistical significance was set at a P<0.05.

RESULTS

Follicular gastritis was associated with Helicobacter pylori infection (OR: 13.41, CI: 1.7-103, P=0.01). The CagA+ genotype was present in 56.5% of the cases and 58% of the controls. The cytotoxic VacAs1m1strain was present in 82% of the isolates in both groups. IceA1 frequency was 34.8% in the cases and 26% in the controls and the difference was not statistically significant.

CONCLUSIONS

The population studied had elevated frequencies of cytotoxic Helicobacter pylori strains and the iceA1 genotype was more frequent in follicular gastritis.

Hepatitis C Virus-Associated Non-Hodgkin Lymphomas: Biology, Epidemiology, and Treatment

Eradication of hepatitis C virus (HCV) in indolent non-Hodgkin lymphomas (NHLs), especially in marginal zone lymphomas, determines the regression of the hematologic disorder in a significant fraction of cases. Because direct antiviral agents show an excellent profile in terms of efficacy, safety, and rapid onset of action, these drugs can be used in any clinical situation and in the presence of any comorbidities. To avoid the progression of the NHL, despite HCV eradication, antiviral therapy should be provided as soon as the viral infection is discovered; before that, the chronic antigenic stimulation determines the irreversible proliferation of neoplastic B cells.

Multifocal Gastric Ulcers Caused by Diffuse Large B Cell Lymphoma in a Patient With Significant Weight Loss

Primary gastrointestinal (GI) lymphoma is a heterogeneous disease with varied clinical presentations. The stomach is the most common GI site and accounts for 70% to 75% of GI lymphomas. We present a patient with gastric diffuse large B cell lymphoma (DLBCL) who presented with significant weight loss, early satiety, and multifocal ulcerated gastric lesions. Esophagoduodenoscopy should be performed in patients presenting with warning symptoms as in our case. Diagnosis is usually made by endoscopic biopsies. Multiple treatment modalities including surgery, radiotherapy, and chemotherapy have been used. Advancements in endoscopic and pathologic technology decrease turnaround time for diagnosis and treatment initiation, thus reducing the need for surgery. Health care providers should maintain a high level of suspicion and consider gastric DLBCL as part of the differential diagnosis, especially in those with warning symptoms such as weight loss and early satiety with abnormal endoscopic findings.

[Radiotherapy for localized gastric and orbital MALT lymphomas]

Primary gastric and orbital MALT lymphomas are both low grade (indolent) B-cell non-Hodgkin's lymphomas. Traditionally, these tumors are radiosensitive and have a good prognosis. In localized orbital and stages IE-IIE gastric MALT lymphomas without Helicobacter pylori infection or in case of persistent H. pylori infection after eradication therapy, several retrospective studies have shown that radiotherapy was an effective and well-tolerated treatment.

Study of the clinical relevance of Helicobacter pylori virulence genes to gastric diseases among Egyptian patients

BACKGROUND AND STUDY AIMS

Helicobacter pylori infection is common in Egypt. It has been associated with gastritis, ulcers and it is a risk factor for gastric cancer. We aimed to study the correlation between the presence of H. pylori virulence factors and the histopathological and endoscopic findings in gastric biopsies.

PATIENTS AND METHODS

Gastric biopsies from thirty seven patients scheduled for diagnostic endoscopy in Cairo University hospital were included in the study. All gastric biopsies were subjected to histopathological examination and PCR assay for detection of 16S rRNA gene to diagnose H. pylori infection, detection of H. pylori virulence factors by PCR for cagA and vacA genotypes and serological analysis of H. pylori (cagA, vacA, P25, and P19) IgG antibodies by immunoblot assay were done.

RESULTS

H. pylori infection was detected in 23 (62.2%) cases by histopathology while 28/37 (75.7%) were positive for H. pylori 16S rRNA gene by PCR. By PCR seventeen samples out of 37 (45.9%) were positive for cagA gene and five (13.5%) for cag empty site gene.

CONCLUSION

The most common vacA genotype identified was vacA s2m2 genotype in 10 (27.02%). No statistical correlation was found between IgG antibodies against different antigens of H. pylori virulence factors (cagA, vacA, p25, and p19) and the degree of gastritis except for IgG antibodies against the UreA antigen.

Staging of Primary Abdominal Lymphomas: Comparison of Whole-Body MRI with Diffusion-Weighted Imaging and (18)F-FDG-PET/CT

Background. The purpose of this study was to compare the accuracy of whole-body MRI with diffusion-weighted sequences (WB-DW-MRI) with that of ¹⁸F-FDG-PET/CT in the staging of patients with primary gastrointestinal lymphoma. Methods. This retrospective study involved 17 untreated patients with primary abdominal gastrointestinal lymphoma. All patients underwent ¹⁸F-FDG-PET/CT and WB-DW-MRI. Histopathology findings or at least 6 months of clinical and radiological follow-up was the gold standard. The Musshoff-modified Ann Arbor system was used for staging, and diagnostic accuracy was evaluated on a per-node basis. Results. WB-DW-MRI exhibited 100% sensitivity, 96.3% specificity, and 96.1% and 100% positive and negative predictive values (PPV and NPV), respectively. The sensitivity, specificity, and PPV and NPV of PET/CT were 95.9%, 100%, and 100% and 96.4%, respectively. There were no statistically significant differences between the two techniques (p = 0.05). The weighted kappa agreement statistics with a 95% confidence interval were 0.97 (0.95–0.99) between the two MRI readers and 0.87 (0.82–0.92) between the two methods. Conclusions. WB-DW-MRI appears to have a comparable diagnostic value to ¹⁸F-FDG-PET/CT in staging patients with gastrointestinal lymphoma.

Helicobacter pylori infection in gastric mucosa-associated lymphoid tissue lymphoma

Gastrointestinal lymphoma is the most common type of extranodal lymphoma, and most commonly affects the stomach. Marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT) and diffuse large B-cell lymphoma are the most common histologic types of gastric lymphoma. Despite its increasing incidence, diagnosis of gastric lymphoma is difficult at an earlier stage due to its nonspecific symptoms and endoscopic findings, and, thus, a high index of suspicion, and multiple, deep, repeated biopsies at abnormally and normally appearing sites in the stomach are needed. In addition, testing for Helicobacter pylori (H. pylori) infection and endoscopic ultrasonography to determine the depth of tumor invasion and involvement of regional lymph nodes is essential for predicting response to H. pylori eradication and for assessment of disease progression. In addition, H. pylori infection and MALT lymphoma development are associated, and complete regression of low-grade MALT lymphomas after H. pylori eradication has been demonstrated. Radiotherapy and/or chemotherapy can be used in cases that show poor response to H. pylori eradication, negativity for H. pylori infection, or high-grade lymphoma.

Extranodal and splenic small B-cell lymphoma

Although almost any non-Hodgkin lymphoma can involve the spleen or an extranodal site as part of more widely disseminated disease, there is a group of small B-cell lymphomas that specifically arise in these locations. These are important to recognise as some appear to have a behaviour and prognosis that is distinct from their nodal counterparts. In addition, there are entities that are specific to extranodal locations (such as extranodal marginal zone lymphoma) and to the red or white pulp of the spleen. In this review, the characteristics of these entities will be presented as well as clues to help distinguish lymphoma from reactive infiltrates in extranodal sites and measure to distinguish between small B-cell lymphomas encountered in the spleen and at extranodal locations.

A case of gastric mucosa-associated lymphoid tissue lymphoma in which magnified endoscopy with narrow band imaging was useful in the diagnosis

Recently, we reported a case of gastric mucosa-associated lymphoid tissue (MALT) lymphoma presenting with unique vascular features. In the report, we defined the tree-like appearance (TLA) on the images of abnormal blood vessels which resembled branches from the trunk of a tree in the shiny mucosa, in which the glandular structure was lost. The 67-year-old female was diagnosed with gastric MALT lymphoma. The patient received eradication therapy for H. pylori. Conventional endoscopy revealed multiple ill-delineated brownish depressions in the stomach and cobblestone-like mucosa was observed at the greater curvature to the posterior wall of the upper gastric body 7 mo after successful eradication. Unsuccessful treatment of gastric MALT lymphoma was suspected on conventional endoscopy. Conventional endoscopic observations found focal depressions and cobblestone-like appearance, and these lesions were subsequently observed using magnified endoscopy combined with narrow band imaging to identify abnormal vessels presenting with a TLA within the lesions. Ten biopsies were taken from the area where abnormal vessels were present within these lesions. Ten biopsies were also taken from the lesions without abnormal vessels as a control. A total of 20 biopsy samples were evaluated to determine whether the diagnosis of MALT lymphoma could be obtained histologically from each sample. A positive diagnosis was obtained in 8/10 TLA (+) sites and in 2/10 TLA(-) sites. Target biopsies of the site with abnormal blood vessels can potentially improve diagnostic accuracy of gastric MALT lymphoma.

Lymphoproliferative disorders of the gastrointestinal tract: a review and pragmatic guide to diagnosis

CONTEXT

The gastrointestinal tract is the most common site of extranodal lymphomas. Although all histologic categories of malignant lymphoma develop in the gastrointestinal tract, large B-cell lymphomas predominate, followed by extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT) type; the latter is especially prevalent in stomach. The acceptance of extranodal marginal zone lymphoma of MALT type as a clinicopathologic entity has reduced the number of cases that formerly were interpreted as florid lymphoid hyperplasia ("pseudolymphoma"). Nonetheless, the distinction of lymphoid hyperplasia from a lymphoma of MALT type in small biopsy specimens remains problematic.

OBJECTIVE

To assess the relevant morphologic, immunologic, molecular, and genetic properties of gastrointestinal lymphomas and to present a feasible tactic for diagnosis, expressly for small biopsy specimens.

DATA SOURCES

Case-derived material and literature review using PubMed (National Library of Medicine).

CONCLUSIONS

Most gastrointestinal lymphomas are readily amenable to an unqualified diagnosis, primarily those cases consisting of monomorphic large cells whether of B- or T-cell lineage, including cases associated with enteropathy. Diagnosis for infiltrates dominated by small lymphocytes remains taxing, as the differential diagnosis embraces not only MALT lymphoma and lymphoid hyperplasia but also mantle cell lymphoma, follicular lymphoma, and chronic lymphocytic leukemia/small lymphocytic lymphoma. Adherence to strict morphologic criteria is the standard for diagnosis, but these criteria should be augmented by immunologic studies together with judicious use of molecular techniques to determine clonality. In establishing a diagnosis of gastric marginal zone lymphoma of MALT type, determination of t(11;18)(q21;q21) status may be required since this translocation has clinical ramifications.

Successful treatment of mucosa-associated lymphoid tissue lymphoma in a patient with gastric and rectal lesions with metachronous and ectopic development

A 75-year-old female, who had an abnormal stomach x-ray finding, was admitted to the hospital for further examination and therapy. Upper GI endoscopy showed reddish and swollen folds on the greater curvature of the gastric body and a biopsy was of this lesion revealed malignant lymphoma (small cell type or mucosa-associated lymphoid tissue (MALT) lymphoma suspected). The patient was infected with Helicobacter pylori (H. pylori), however, in response to the patient's wishes, a total gastrectomy, omentectomy and splenectomy were performed and the histological diagnosis was gastric MALT lymphoma. Two courses of CHOP therapy (cyclophosphamide (CPM) 750 mg/m²/day, day 1, adriamycin (ADM) 50 mg/m²/day, day 1, vincristine sulfate (VCR) 1.4 mg/m²/day, day 1, prednisolone 100 mg/body, day 1–5) were administered as adjuvant chemotherapy. A colonoscopic examination performed about 4.5 yr after the operation revealed rectal submucosal tumors and the biopsied specimens were diagnosed as malignant lymphoma. A transanal focal resection was performed and the histological diagnosis was metachronous and ectopic development of MALT lymphoma. The histological finding was similar to the gastric lesion. About 4 and 7 yr after the first development of rectal MALT lymphoma, MALT lymphomas developed repeatedly in the rectal lesion, however, these were resected repeatedly and no developmenthas occurred during the past two years. This report presents a very rare case of metachronous and ectopic MALT lymphoma development in the gastric and rectal lesions.

Role of F-FDG PET Scans in Patients with Helicobacter pylori-Infected Gastric Low-Grade MALT Lymphoma

Background/Aims

Endoscopic ultrasound (EUS) plays a crucial role in the assessment and treatment of low-grade gastric mucosa-associated lymphoid tissue (MALT) lymphoma; however, interobserver variation, inadequate accuracy in judging the depth of tumor invasion, and histological heterogeneity of the tumor can limit its role. Thus, we have assessed the role of ¹⁸F-FDG PET scans in the management of Helicobacter pylori-infected gastric MALT lymphoma.

Methods

Eighteen patients with H. pylori-infected low-grade gastric MALT lymphoma underwent an ¹⁸F-FDG PET scan prior to receiving H. pylori eradication therapy. We analyzed these patients' clinicopathologic data and measured the baseline and change in the metabolic activity of the tumor using standardized uptake values (SUVs).

Results

Two patients failed to achieve complete remission of the low-grade gastric MALT lymphoma after successful H. pylori eradication. The baseline SUVs were significantly higher in these patients compared to successfully treated patients, 13.35±0.07 vs 2.98±0.93, respectively (n=2 vs n=16, p<0.001). The reduction in the SUV was significantly greater in the complete remission patients compared to treatment failure patients (p=0.018).

Conclusions

A high SUV at baseline ¹⁸F-FDG PET and a lower reduction in the SUV within 3 months after eradication therapy are associated with treatment failure in H. pylori-positive low-grade gastric MALT lymphoma patients undergoing eradication treatment.

Gastric lymphoma: the histology report

The diagnosis of gastric MALT lymphoma is frequently difficult for the general histopathologist. During recent years there have been relevant changes in the therapeutic approach to gastric MALT lymphoma and our knowledge about its pathogenesis has greatly improved. The management of this disease actually requires a close cooperation between the histopathologist and the clinicians. The histology report of biopsies of a newly diagnosed or of an already treated case implies information of clinical and therapeutical relevance. This paper aims at giving the histopathologist a general knowledge about the state of art of this disease and its management. The diagnostic process leading to a complete and competent report is then described step by step.

Clonal relationship of extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue involving different sites

Patients with mucosa-associated lymphoid tissue (MALT) lymphoma often have multiple sites of disease at initial diagnosis or during the clinical course. The neoplasms at multiple sites are often presumed to be identical, indicating dissemination or relapse. However, evidence to support this presumption is usually not available. We compared IGH VDJ sequences in 4 patients with 2 sequential sites of MALT lymphoma. The specimen pairs were stomach and nasopharynx, stomach and lung, ocular adnexa and nasopharynx, and ocular adnexa and parotid gland. The median interval between biopsies was 4 months (range, 1-32 months). Monoclonal IGH gene rearrangement was detected in all cases. In 3 patients, the VDJ sequences were distinct; in 1 patient the 2 biopsy specimens shared the same clone. MALT lymphomas involving multiple sites in a patient are usually not clonally related but arise independently, likely due to chronic antigenic stimulation, inducing oligoclonal B-cell proliferations and eventually a dominant B-cell clone.

Diagnosis and staging in gastrointestinal lymphoma

The diagnosis gastrointestinal lymphoma can be made on endoscopic biopsies in the vast majority of cases. Definitive subtyping of the lymphoma according to the WHO classification with the use of additional immunological and molecular markers is the cornerstone for further decision making. Several lymphomas may occur multifocally or show both small cell and large cell components. Therefore, a second endoscopy with an extensive biopsy protocol (mapping) may be mandatory. Staging procedures are required for therapeutic decision making and should include CT-scan, laboratory studies and bone marrow examination as required in other lymphomas. Additional studies must be performed depending subtype and localisation of the lymphoma. In gastric lymphoma endosonography reveals prognostic information. In marginal zone lymphoma of MALT-type attention to other MALT-sites and autoimmune diseases is necessary. In enteropathy-associated T-cell lymphoma screening for coeliac disease and enteroscopy are required. In several lymphomas (diffuse large B-cell lymphoma and mantle cell lymphoma) a PET-scan is considered as standard of care. The value of staging procedures after treatment is less well defined. At least in gastric lymphomas, histology is the gold standard after treatment and during follow-up.

Gastric MALT lymphoma B cells express polyreactive, somatically mutated immunoglobulins

Gastric B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) arises against a background of chronic inflammation caused by persistent Helicobacter pylori infection. The clinical and histopathologic features of the human tumor can be reproduced by Helicobacter infection of BALB/c mice. In this study, we have analyzed the antibody sequences and antigen specificity of a panel of murine and human MALT lymphoma-derived antibodies. We find that a majority of tumors in patients as well as experimentally infected mice are monoclonal. The tumor immunoglobulin heavy chain genes have undergone somatic hypermutation, and approximately half of all tumors show evidence of intraclonal variation and positive and/or negative selective pressure. Recombinantly expressed MALT lymphoma antibodies bind with intermediate affinity to various unrelated self- and foreign antigens, including Helicobacter sonicate, immunoglobulin G (IgG), DNA, and stomach extract; antigen binding is blocked in a dose-dependent manner in competitive enzyme-linked immunosorbent assays. A strong bias toward the use of V(H) gene segments previously linked to autoantibodies and/or polyreactive antibodies in B-cell malignancies or autoimmune pathologies supports the experimental finding of polyreactivity. Our results suggest that MALT lymphoma development may be facilitated by an array of local self- and foreign antigens, providing direct antigenic stimulation of the tumor cells via their B-cell receptor.

Primary extranodal lymphomas of stomach: clinical presentation, diagnostic pitfalls and management

Gastrointestinal lymphoma is the most common form of extranodal lymphoma, accounting for 30%-40% of cases. The most commonly involved site is the stomach (60%-75% of cases), followed by the small bowel, ileum, cecum, colon and rectum. The most common histological subtypes are diffuse large B-cell lymphoma (DLBCL) and marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT). Helicobacter pylori infection has been implicated in the pathogenesis of MALT gastric lymphoma, but its role in gastric diffuse large B-cell non-Hodgkin's lymphoma (NHL) is controversial. The therapeutic approach for patients with gastric NHL has been revised over the last 10 years. Conservative treatment with anthracycline-based chemotherapy alone or in combination with involved-field radiotherapy has replaced gastrectomy as standard therapy in cases with DLBCL. Additionally, MALT lymphomas are mainly treated with antibiotics alone, which can induce lasting remissions in those cases associated with H. pylori infection. Nevertheless, various therapeutic aspects for primary gastric lymphomas are still controversial and several questions remain unanswered. Among others, the role of rituximab, consolidation radiotherapy as well as H. pylori eradication in histological aggressive subtypes warrants better clarification.

Primary gastric mucosa associated lymphoid tissue lymphoma: Clinical data predicted treatment outcome

AIM: To determine clinical characteristics and treatment outcome of gastric lymphoma after chemotherapy and immuno-chemotherapy.

METHODS: Thirty four patients with primary gastric mucosa associated lymphoid tissue (MALT) lymphoma (Ann Arbor stages I to IV) were enrolled. All had upper gastric endoscopy, abdominal ultrasonography, CT and H pylori status assessment (histology and serology). After anti-H pylori treatment and initial chemotherapy, patients were re-examined every 4 mo.

RESULTS: Histological regression of the lymphoma was complete in 22/34 (64.7%) and partial in 9 (26.5%) patients. Median follow up time for these 31 responders was 60 mo (range 48-120). No regression was noted in 3 patients. Among the 25 (73.5%) H pylori positive patients, the eradication rate was 100%.

CONCLUSION: Using univariate analysis, predictive factors for overall survival were international prognostic index (IPI) score, hemoglobin level, erythrocyte sedimentation rate (ESR), and platelet numbers (P < 0.005). In addition to this, Cox proportion hazard model differentiate IPI score, ESR, and platelets as predictors of survival.

Marginal-zone lymphoma

The term marginal-zone lymphoma (MZL) encompasses three closely related lymphoma subtypes, namely the "low-grade B-cell lymphoma of MALT type" currently named MALT lymphoma, the "nodal marginal-zone B-cell lymphoma" and a provisional entity in the REAL classification named "primary splenic MZL with or without villous lymphocytes". These entities display different characteristics, with evident clinical and biological variations according to the organ where the lymphoma arises. Marginal-zone B-cells are functionally heterogeneous and may differ with respect to the pattern of somatic hypermutation in their Ig variable genes. Sequence and mutation analysis of the rearranged Ig heavy chain variable genes and that somatic mutations pattern indicate that MZL may arise from different subsets of marginal-zone B-cells. Pathogenesis of these groups of lymphomas is correlated to chronic infections, like Helicobacter pylori, hepatitis C virus, Campylobacter jejuni, Chlamydia psittaci and Borrelia burgdorferi. Several therapeutic strategies against these malignancies exist. Surgical resection, radiotherapy and alkylating agent-based chemotherapy constitute standard approaches, while antimicrobial therapies, anti-CD20 therapy and new forms of immunotherapy constitute interesting experimental approaches. However, prospective trials on these malignancies are rare and universally accepted therapeutic guidelines do not exist. MZLs constitute an exciting investigational setting both from molecular and clinical points of view.

Therapy of gastric mucosa associated lymphoid tissue lymphoma

Gastric mucosa associated lymphoid tissue (MALT) lymphoma has recently been incorporated into the World Health Organization (WHO) lymphoma classification, termed as extranodal marginal zone B-cell lymphoma of MALT-type. In about 90% of cases this lymphoma is associated with H pylori infection which has been clearly shown to play a causative role in lymphomagenesis. Although much knowledge has been gained in defining the clinical features, natural history, pathology, and molecular genetics of the disease in the last decade, the optimal treatment approach for gastric MALT lymphomas, especially locally advanced cases, is still evolving. In this review we focus on data for the therapeutic, stage dependent management of gastric MALT lymphoma. Hence, the role of eradication therapy, surgery, chemotherapy and radiotherapy is critically analyzed. Based on these data, we suggest a therapeutic algorithm that might help to better stratify patients for optimal treatment success.

Therapy of gastric mucosa-associated lymphoid tissue lymphoma

Mucosa-associated lymphoid tissue (MALT) lymphoma is a relatively common lymphoma and comprises approximately 7% of all newly diagnosed non-Hodgkin's lymphoma. It is mainly located in the stomach and has become a focus of interest due to its unique pathophysiological link with Helicobacter pylori (HP) and the consecutive response to HP eradication therapy. In view of this, HP eradication has become standard treatment for patients with localised disease, and recent data have suggested that HP-negative patients might benefit from antibiotic treatment. In case of non-response, however, the standard approach in such patients is unclear. Both radiation and chemotherapy have shown promising results, and at present there is only one randomised study, which nevertheless suggests chemotherapy as management of choice. The objective of this review is, therefore, to summarise and evaluate the data available for treatment of gastric MALT lymphoma and to highlight potential focus for further research.

Radiotherapy for low-grade gastric marginal zone lymphoma: a retrospective study

BACKGROUND

We evaluated the efficacy and toxicity of radiotherapy (RT) in patients with low-grade gastric marginal zone lymphoma.

METHODS

A retrospective review of consecutive cases of gastric marginal zone lymphoma treated by radical RT at the Peter MacCallum Cancer Centre and Radiation Oncology Victoria between January 1980 and September 2003 was carried out.

RESULTS

Eighteen patients (11 men and 7 women) were identified. The median age at commencement of RT was 65 years (range 42-84 years). Prior treatment included Helicobacter pylori eradication in 12 patients, chemotherapy in 7 and surgery in 2, whereas 2 patients had no prior therapy. The median time to progression after commencement of last treatment before RT was 4.8 months (range 0-129.4 months). The radiation fields included the stomach plus perigastric and coeliac nodes in 15 patients (83%), stomach plus spleen in 2 patients (11%) and stomach plus para-aortic nodes in 1 patient (6%). The median RT dose was 30 Gy (range 30-36 Gy) in a median 20 fractions (range 17-24 fractions). One patient required treatment interruption for acute toxicity. A complete response on post-RT biopsies was achieved in 17 of 18 patients (94%). With a median follow up of 4.5 years after RT, 3 of these 17 patients (18%) have had a recurrence. At the last follow up, 11 patients were alive in continuous complete histological remission. No late renal toxicity was identified.

CONCLUSION

Radiotherapy is an effective, well-tolerated treatment for patients with low-grade gastric marginal zone lymphoma, including those who have had prior therapy.

Non-Hodgkin's lymphoma of mucosa-associated lymphoid tissue

The concept of mucosa-associated lymphoid tissue (MALT) lymphomas was introduced by Isaacson and Wright [Cancer 1983; 52:1410-1416] in 1983. After more than 20 years of clinical research MALT lymphomas are now recognized as a distinct subtype of non-Hodgkin's lymphoma (NHL) with unique pathogenic, histological, and clinical features. Although this subtype of NHL occurs frequently, optimal management remains elusive. This manuscript reviews features of the clinical presentation, diagnosis, pathology, molecular characteristics, and management of both gastric and non-gastric MALT lymphoma.

Primary gastrointestinal tract lymphoma: diagnosis and management of common neoplasms

Primary gastrointestinal lymphoma represents the most common location of extranodal lymphoma. With the bulk of disease manifesting within the gastrointestinal tract and contiguous lymph nodes, many of the lymphomas occurring in the peripheral lymph nodes can also present with primary gastrointestinal tract involvement. Molecular biology has recently enabled significant progress in the diagnosis and management of primary gastrointestinal lymphoma. Herein, we will discuss the major lymphomas affecting the bowel and highlight their key morphological, immunophenotypical and molecular diagnostic attributes. Similarly, in keeping with recent therapeutic advances, we will briefly discuss some important treatment considerations. Thus, this review is intended to offer clinicians and pathologists an overview of primary gastrointestinal lymphomas.

Primary gastric lymphoma pathogenesis and treatment: what has changed over the past 10 years?

Primary gastric (PG) lymphomas are generally non-Hodgkin lymphomas (NHL). They represent 5% of gastric malignancies and show an apparently increasing incidence worldwide. The most common histological subtypes are diffuse large B-cell and marginal zone B-cell NHL of the mucosa-associated lymphoid tissue (MALT)-type. Pathogenesis is often related to Helicobacter pylori infection (HPI). There is still no consensus on the optimal treatment for PG lymphoma. Nowadays surgery is limited to rare cases and radiotherapy--combined or not with chemotherapy--represents an effective therapeutic option ensuring long-term, organ-salvage benefits mainly in aggressive histological subtypes. Additionally, the description of MALT lymphomas has made the situation even more complex, because antibiotics alone can induce lasting remissions in those cases associated with HPI. Consequently, a global therapeutic approach to the cure of PG-NHL has completely changed over the last 10 years: innovative, conservative options to reduce treatment toxicity, thus preventing systemic relapses, have made their appearance and are on the rise.

Reverse Transcription-PCR for t(11;18)(q21;q21) Staging and Monitoring in Mucosa-Associated Lymphoid Tissue Lymphoma

PURPOSE

Subclinical dissemination as well as persistence after therapy may be difficult to assess on clinical and histologic examinations in patients with mucosa-associated lymphoid tissue (MALT) lymphoma. We have analyzed the use of reverse transcription-PCR (RT-PCR) for the detection of t(11;18)(q21;q21) in histologically infiltrated and normal biopsies at diagnosis and during follow-up to determine its clinical and prognostic effect.

EXPERIMENTAL DESIGN

Twenty-one patients with t(11;18)(q21;q21)+ MALT lymphoma were included in this retrospective study. Presence of t(11;18)(q21;q21) was determined by RT-PCR done on 316 biopsies of various tissues obtained during staging and follow-up.

RESULTS

Infiltration with lymphoma was histologically detected in 67 of 316 biopsies, whereas molecular infiltration was established in 104 of 316 biopsies. All histologically positive specimens were also positive in RT-PCR. There was a good concordance (P = 0.0001) between histology and RT-PCR at the time of disease presentation with only one further infiltration site identified by RT-PCR. In 8 of 12 patients with persistent lymphoma, RT-PCR revealed tumor infiltration in histologically unsuspected sites. Eight of nine treated patients with histologic and clinical complete remission (CR) remained RT-PCR positive. CR on RT-PCR was achieved later than histologic CR (between 13-59 months) without any further therapy in five of these eight patients; only one patient with persistent t(11;18)(q21;q21) relapsed histologically.

CONCLUSIONS

This study shows the potential of RT-PCR for t(11;18)(q21;q21) done on routine paraffin-embedded specimens to identify disseminated disease in tissues otherwise not diagnostic of MALT lymphoma involvement. T(11;18)(q21;q21) persistence in patients with clinical and histologic CR does not necessarily require therapeutic intervention.

Assessment of Disease Dissemination in Gastric Compared With Extragastric Mucosa-Associated Lymphoid Tissue Lymphoma Using Extensive Staging: A Single-Center Experience

Purpose

Molecular data and preliminary clinical findings have suggested mucosa-associated lymphoid tissue (MALT) lymphoma as a multifocal disease in a high percentage of patients. We report our findings with an extensive staging routine applied in patients diagnosed with MALT lymphoma at our institution.

Patients and Methods

A total of 140 consecutive patients (61 with gastric and 79 with extragastric MALT lymphoma) underwent staging according to a standardized protocol. Staging included gastroscopy with multiple biopsies, endosonography of the upper GI tract, computed tomography of thorax and abdomen, lymph node sonography, colonoscopy with multiple biopsies, otorhinolaryngologic assessment, magnetic resonance imaging of salivary and lacrimal glands, and bone marrow biopsy. All lesions suggestive of lymphoma involvement were subjected to biopsy, if accessible, and biopsies were evaluated for MALT lymphoma–specific genetic aberrations by means of reverse transcriptase polymerase chain reaction and/or fluorescent in situ hybridization.

Results

Fifteen (25%) of 61 patients with gastric MALT lymphoma had multiorgan involvement, with dissemination beyond the GI tract in six patients. By contrast, significantly more patients with extragastric MALT lymphoma had dissemination to another MALT organ (37 of 79 patients, 46%; P = .045). Nine of these 37 patients had dissemination to the stomach. Only three (2%) of 140 patients had bone marrow involvement. Multifocality was significantly associated with t(11;18)(q21;q21) in gastric lymphomas (P = .045) and with trisomy 18 in extragastric lymphomas (P = .011).

Conclusion

Our findings suggest that MALT lymphoma frequently presents as a multifocal disease. Extragastric MALT lymphomas are significantly more prone to dissemination than gastric MALT lymphomas.

Clinical and endoscopic presentation of primary gastric lymphoma: a multicentre study

BACKGROUND

Although the stomach is the most frequent site of intestinal lymphomas, few data are available on both clinical endoscopic presentation of gastric lymphoma and possible differences between low-grade and high-grade lymphomas.

METHODS

Clinical, histological and endoscopic records of consecutive patients with primary low-grade or high-grade lymphoma diagnosed were retrieved. Symptoms were categorized as 'alarm' or 'not alarm'. The endoscopic findings were classified as 'normal' or 'abnormal'.

RESULTS

Overall, 144 patients with primary gastric lymphoma were detected, including 74 low-grade and 70 high-grade lymphoma. Alarm symptoms, particularly persistent vomiting and weight loss, were more frequently present in patients with high-grade lymphoma than in those with low-grade lymphoma (54% vs. 28%; P = 0.002). Low-grade lymphomas presented as 'normal' appearing mucosa (20% vs. 0%; P = 0.0004) or petechial haemorrhage in the fundus (9% vs. 0%; P = 0.02) more frequently than high-grade lymphomas, being also more often confined to the antrum (47% vs. 27%, P = 0.03) and associated with Helicobacter pylori infection (88% vs. 52%, P < 0.0001). On the contrary, high-grade lymphomas presented more commonly as ulcerative type (70% vs. 52%; P = 0.03), being also more frequently diagnosed in stage >I when compared with low-grade lymphomas (70% vs. 21%, P < 0.0001).

CONCLUSIONS

The overall prevalence of alarm symptoms is quite low and may be absent in more than 70% of patients with low-grade lymphoma.

Synchronous Adenocarcinoma and Mucosa-associated Lymphoid Tissue (MALT) Lymphoma in a Single Stomach

BACKGROUND

Synchronous gastric adenocarcinoma and primary gastric mucosa-associated lymphoid tissue (MALT) lymphoma are rare, and the characteristics of these tumors are still unclear.

METHODS

Histology of endoscopic and surgical specimens of 6012 gastric adenocarcinoma and 25 primary gastric MALT lymphoma cases were reviewed.

RESULTS

Five cases of synchronous tumors were found among 25 primary gastric MALT lymphoma patients (20.0%) and among 6012 gastric adenocarcinoma patients (8.3%). Helicobacter pylori was detected only in two cases (40.0%) of these five synchronous cases. In only one case, two types of malignant cells were mingled each other as a colliding tumor. In other four cases, two pathologies coexisted separately. These two types of malignant tumors were not distinguished by endoscopic or gross findings.

CONCLUSIONS

Although gastric adenocarcinoma coexists with MALT lymphoma at a relatively high frequency, synchronous carcinoma can be misinterpreted as a multifocal separated lesion of MALT lymphoma owing to their macroscopic resemblance. Therefore, gastric MALT lymphoma patients should be carefully examined by endoscopy, and any suspicious area must be biopsied considering the possibility of coexisting adenocarcinoma. In addition, etiologies other than H. pylori should be considered in these synchronous tumors.

Clinical Activity of Rituximab in Gastric Marginal Zone Non-Hodgkin's Lymphoma Resistant to or Not Eligible for Anti–Helicobacter Pylori Therapy

Purpose

Preliminary results using rituximab in extranodal marginal zone (MALT) non-Hodgkin's lymphoma (NHL) patients seem to indicate a relevant clinical activity. Aim of the present study is to investigate the efficacy of conventional weekly treatment using rituximab in gastric MALT NHL patients resistant/refractory or not suitable for eradication treatment, and to evaluate the relevance of the t(11; 18)(q21; q21) translocation and its possible role as a predictive criteria of response.

Patients and Methods

Twenty-seven patients presenting with gastric MALT NHL at any stage, relapsed/refractory to initial treatment or not suitable for eradication were treated with rituximab in a weekly conventional schedule and evaluated for response and relapse. Flourescence in situ hybridization (FISH) analysis for the presence of 18q21 translocation was performed in 21 patients and was evaluated with clinical outcome.

Results

Among the 26 evaluated patients, 20 (77%) achieved an objective response. Twelve patients (46%) had a pathological and clinical complete remission, and eight (31%) had a partial response. With a median follow-up of 33 months, only two patients relapsed at 26 and 14 months, respectively. No correlation was founded between FISH analysis and response or relapse.

Conclusion

Our experience seems to confirm the clinical activity of rituximab in gastric MALT NHL patients resistant/refractory to antibiotics treatment or not presenting with clinical evidence of Helicobacter pylori infection. The t(11; 18)(q21; q21) translocation seems not to be a predictive marker to response or to subsequent relapse.

Gastrointestinal lymphoma: where morphology meets molecular biology

Primary gastrointestinal lymphomas are best exemplified by mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach and enteropathy-type T-cell lymphoma (ETL). Both lymphomas were initially recognized on morphological grounds and their identification as distinct clinicopathological entities has subsequently been vindicated following integrated immunophenotypic, molecular, and cellular biological investigations. Delineation of the phenotypic, molecular, and biological properties of these lymphomas at various clinicopathological stages of their development has also provided critical information for the clinical management of patients with these diseases. Here, the histopathology and recent advances in phenotypic and molecular characterization of gastric MALT lymphoma and ETL and their applications in diagnosis and clinical management are reviewed.

Extranodal marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue?type of the orbit and ocular adnexa

Non-Hodgkin's lymphomas of the orbit and ocular adnexa (OOA), the majority of which are extranodal marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue-type (MALT lymphomas), are a rare disorder. The aim of this study was to evaluate the clinical features and treatment outcomes and complications in patients with MALT lymphoma of OOA. Thirty-seven patients with a histologically verified diagnosis of MALT lymphoma of OOA were included in this retrospective, observational case study. There were 22 (59%) men and 15 (41%) women, with a median age of 44 years (range, 21-80 years). The most common presenting complaint was a slowly growing orbital mass. The stages were IA(E) in 74%, IA(EE) (bilateral involvement) in 18%, IIIA(E) in 6%, and IVA(E) in 3%. None of the patients had an elevated value of LHD or beta(2)-microglobulin. Surgical resection alone was attempted as the sole treatment in two patients, but tumor recurred 19 and 24 months after surgery. Radiotherapy, with a median tumor dose of 3,060 cGy, was administered in 29 patients; all of the patients achieved complete remission, and none of them had severe later complications. Combination chemotherapy alone was employed in three patients with stage IIIA(E) or IVA(E). With a median follow-up duration of 21 months, the 3-year overall survival (OS) rate and event-free survival (EFS) rate were 97% and 86%, respectively. Subgroup analysis of the patients with localized disease, who received radiotherapy as an initial treatment modality, revealed that 3-year OS rate and EFS rate were 100% and 93%, respectively. All disease recurrences were documented histologically as MALT lymphoma. In conclusion complete staging evaluation is needed to select an adequate treatment modality. Radiotherapy alone can produce excellent local control and survival in patients with localized MALT lymphoma of OOA. Systemic chemotherapy should be considered in patients with advanced stages or systemic manifestation.