Helicobacter pylori CagA EPIYA Motif Variations Affect Metabolic Activity in B Cells

Background: Helicobacter pylori (Hp) colonizes the human stomach and can induce gastric cancer and mucosa-associated lymphoid tissue (MALT) lymphoma. Clinical observations suggest a role for the Hp virulence factor cytotoxin-associated gene A (CagA) in pathogenesis. The pathogenic activity of CagA is partly regulated by tyrosine phosphorylation of C-terminal Glu-Pro-Ile-Tyr-Ala (EPIYA) motifs in host cells. However, CagA differs considerably in EPIYA motifs, whose functions have been well characterized in epithelial cells. Since CagA is fragmented in immune cells, different CagA variants may exhibit undetected functions in B cells. Methods: B cells were infected with Hp isolates and isogenic mutants expressing different CagA EPIYA variants. CagA translocation and tyrosine phosphorylation were investigated by Western blotting. Apoptosis was analyzed by flow cytometry and metabolic activity was detected by an MTT assay. Results: Isogenic CagA EPIYA variants are equally well translocated into B cells, followed by tyrosine phosphorylation and cleavage. B cell apoptosis was induced in a CagA-independent manner. However, variants containing at least one EPIYA-C motif affected metabolic activity independently of phosphorylation or multiplication of EPIYA-C motifs. Conclusions: The diverse structure of CagA regulates B cell physiology, whereas B cell survival is independent of CagA.

Mucosa-associated lymphoid tissue lymphoma of the trachea associated with idiopathic pulmonary fibrosis: A case report and literature review

RATIONALE

Mucosa-associated lymphoid tissue (MALT) lymphoma of the trachea is a rare disease that has been shown to be associated with chronic antigenic stimulation. There have been few reports of MALT lymphoma of the trachea in association with idiopathic pulmonary fibrosis (IPF).

PATIENT CONCERNS

A 73-year-old patient visited with a 2-year history of dyspnea on exertion and productive cough, which had worsened 1 month ago.

DIAGNOSES

MALT lymphoma of the trachea associated with IPF.

INTERVENTIONS

After taking into consideration the age, poor performance status, and comorbidities of the patient and the extent of disease, we utilized an observational approach as a treatment strategy.

OUTCOMES

The patient is well without any evidence of progression for 12 months since the initial diagnosis.

LESSONS

We present a case of MALT lymphoma of the trachea associated with IPF. A common predisposing factor may exist for tracheal MALT lymphoma and IPF. As there are no randomized clinical trials focusing on tracheal MALT lymphoma, individualized treatment decision is important, and in some cases, simply monitoring the patient might be the most appropriate approach.

[Non-Hodgkin's lymphoma mimicking Mikulicz disease: a case report]

IgG4-related disease is a systemic disorder involving a spectrum of multiple indications, and various histopathological features are shared among different IgG4-related disease subtypes, which challenge diagnosis, although certain syndromes have organ-specific involvement. Among them, Mikulicz's disease affecting the salivary and lacrimal glands, distinguished by often elevated levels of serum IgG4, infiltration of IgG4⁺ plasma cells into target tissues, and diffuse swelling, mass formation, or fibrosis of affected organs. However, there are several diseases, which could manifest as salivary gland swelling, mimicking Mikulicz's disease, such as Sjogren's syndrome, mumps virus infection, obstruction of parotid duct, non-Hodgkin's lymphoma (NHL), and so on. So differential diagnosis is important and essential as to the salivary gland swelling. In this paper, we analyzed a case of a 59-year-old male with symmetric salivary gland swelling. Mikulicz's disease was misdiagnosed at the beginning without biopsy. Prednisone treatment ever seemed to be effective and antibiotics had no effect. Besides salivary involvement, the patient also manifested as testicle swelling and severe pancytopenia with the development of the disease, which rarely appeared in Mikulicz's disease. Physical examination showed skin, sclera yellow dye, swollen submandibular, sublingual and lacrimal gland and splenomegaly. As a result, biopsy of right submandibular gland was made, and mucosa-associated lymphoid tissue lymphoma was confirmed by morphology and immunohistochemistry. Bone marrow biopsy also confirmed that lymphoma cells were found in the bone marrow. Finally, the diagnosis of mucosa-associated lymphoid tissue lymphoma (Phase IVE, Group A) was made on the patient, who was transferred to the hematology department for the treatment. NHL, especially, primary extranodal lymphoma usually involves the salivary gland, and painless swelling of the salivary gland is a common manifestation, similar with Mikulicz's disease. So although salivary gland swelling is often associated with autoimmune diseases such as Sjogren's syndrome and IgG4-related disease, the awareness and suspicion of a possibility of NHL are essential for rheumatologists. Biopsy is a necessary examination to decrease or avoid misdiagnosis.

Primary pulmonary MALT lymphoma - case report and literature overview

OBJECTIVE

Primary pulmonary lymphomas (PPL) are rarely taken into consideration in the differential diagnosis of lung lesions. The aim of this report is to characterize the symptoms, diagnosis and treatment of primary MALT lymphoma of the lung.

CASE REPORT

We present the case of a 48-year-old man who was admitted to hospital with a history of coughing, fever, fatigue and non-specific lesions on his chest X-ray.

RESULTS

The patient was treated for pneumonia, but showed no improvement. A computer tomography revealed atypical lesions. After an initial examination and tests, no diagnosis could be established. A thoracotomy with an open lung biopsy was performed and MALT lymphoma was finally diagnosed. The patient underwent chemotherapy and showed a significant improvement.

CONCLUSIONS

Primary MALT lymphoma is a rare disease and its diagnosis is difficult. There is no non-invasive test that is specific enough, so a proper diagnosis can only be established by a histopathological examination. The disease has a slow and mild course and the response to treatment is satisfactory.

MALT lymphoma of the small bowel with protein-losing enteropathy

Mucosa-associated lymphoid tissue (MALT) lymphoma usually arises from chronic inflammation. We herein report a case of small intestinal MALT lymphoma with protein-losing enteropathy (PLE). A 73-year-old woman presented with lower leg edema and severe hypoalbuminemia. She had a medical history of pylorus-preserving pancreaticoduodenectomy with Billroth II reconstruction. Oral and anal route double-balloon enteroscopies revealed irregular nodular mucosal lesions with erosion extending from the jejunum to terminal ileum. Histopathological evaluation of the biopsied mucosa showed proliferation of small-to-medium-sized lambda light chain-restricted B cells. Plasmacytic differentiation and lymphoepithelial lesions were present, leading to the diagnosis of MALT lymphoma. Tc-99m albumin scintigraphy indicated tracer exudation in the small bowel, suggesting the presence of PLE. Combination immunochemotherapy with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP) regimen improved both MALT lymphoma and PLE, whereas rituximab monotherapy was not successful. This case is considered to be common type of MALT lymphoma at an uncommon site and is distinct from immunoproliferative small intestinal disease (IPSID). To our knowledge, this is the first case of non-IPSID-type small intestinal MALT lymphoma complicated by PLE. Gastrointestinal reconstruction may be responsible for underlying chronic inflammation via small intestinal bacterial overgrowth.

Rare case of a primary non-dural central nervous system low grade B-cell lymphoma and literature review

We present a case of a 70-year-old HIV negative man with a five-year history of progressive dysnomia and new onset right extremity numbness, dysarthria, and blurry vision. On magnetic resonance imaging (MRI), an infiltrative enhancing tumor was noted. Follow up brain biopsy results revealed a small lymphocytic infiltrate with scattered plasma cells in a predominantly perivascular growth pattern. Flow-cytometric findings revealed a lambda monotypic B-cell population. The morphology and the flow cytometric findings were consistent with involvement by a low grade B-cell lymphoma. Subsequent positron emission tomography (PET) studies along with bone marrow biopsy and serum protein electrophoresis showed no evidence of systemic disease. The above findings are consistent with involvement by a non-dural extranodal marginal zone B-cell lymphoma (MZBCL) primary to the central nervous system (CNS). This is the first reported case of a primary CNS MZBCL with flow cytometric analysis. A review of literature on this rare entity is also included.

Lymphoid proliferations of indeterminate malignant potential arising in adults with common variable immunodeficiency disorders: unusual case studies and immunohistological review in the light of possible causative events

Patients with common variable immunodeficiency disorders (CVIDs) who developed B cell lymphoproliferation of indeterminate malignant potential are described in order to raise a discussion of the relationship between infection and lymphoproliferation in infection prone patients. Those with CVID are at risk of developing either polyclonal or monoclonal lymphoproliferation in part due to the dysregulation of their adaptive immune systems. The aetiologies of the lymphoproliferations are unknown but intriguing; the relevance of infection being particularly problematic. The patients described here demonstrate variability in preceding infection, age at presentation, response to antibiotics and other types of therapy as well as outcome. The question of treatment is also controversial; issues include whether antibiotics or chemotherapy are the first line of therapy in all patients and whether transformation to aggressive B cell malignancy is inevitable or depends on other factors and if so, the length of time for such progression.

Aberrant NF-kappaB signaling in lymphoma: mechanisms, consequences, and therapeutic implications

The transcription factor NF-kappaB is a tightly regulated positive mediator of T- and B-cell development, proliferation, and survival. The controlled activity of NF-kappaB is required for the coordination of physiologic immune responses. However, constitutive NF-kappaB activation can promote continuous lymphocyte proliferation and survival and has recently been recognized as a critical pathogenetic factor in lymphoma. Various molecular events lead to deregulation of NF-kappaB signaling in Hodgkin disease and a variety of T- and B-cell non-Hodgkin lymphomas either up-stream or downstream of the central IkappaB kinase. These alterations are prerequisites for lymphoma cell cycling and blockage of apoptosis. This review provides an overview of the NF-kappaB pathway and discusses the mechanisms of NF-kappaB deregulation in distinct lymphoma entities with defined aberrant pathways: Hodgkin lymphoma (HL), diffuse large B-cell lymphoma (DLBCL), mucosa-associated lymphoid tissue (MALT) lymphoma, primary effusion lymphoma (PEL), and adult T-cell lymphoma/leukemia (ATL). In addition, we summarize recent data that validates the NF-kappaB signaling pathway as an attractive therapeutic target in T- and B-cell malignancies.

Helicobacter pylori infection and gastric cancer

Gastric cancer remains a major health burden on many societies claiming hundreds of thousands of lives every year. The discovery of Helicobacter pylori has no doubt revolutionised our understanding of this malignancy, which is now regarded as a paradigm for infection-induced chronic inflammation-mediated cancer. In this paper, we discuss the evidence for the association between H. pylori and gastric adenocarcinoma and MALT lymphoma. We also discuss the pathogenesis of these two forms of cancer and the factors that determine their outcome. There is no doubt that the knowledge accumulated over the past two decades will be translated into eventual victory over this killer cancer, largely because we now appreciate that the best way to prevent the cancer is by preventing acquisition of the infection in the first place, or by eradicating the infection in infected subjects. Defining the optimal timing of intervention is going to be the challenge facing us over the next two decades.

Intracranial non-Hodgkin's MALT lymphoma mimicking a large convexity meningioma

Primary presentation of an intradural Non-Hodgkin's lymphoma is rare. Recently these B cell lymphomas of mucosa associated lymphoid tissue (MALT) have gained acceptance as an important pathological subtype and are distinguishable from other primary CNS lymphomas that exhibit aggressive behaviour. Over the past decade a number of these lesions have been reported to resemble a meningioma both intra-operatively and radiologically. The authors outline such a case of marginal zone B cell lymphoma that clinically and radiologically resembled a meningioma. This case illustrates the rare occurrence of low grade dural B cell lymphoma and the need to consider this entity in the differential diagnosis of CNS lesions, if appropriate targeted therapy is to be administered.

Comparison of localized gastric mucosa-associated lymphoid tissue (MALT) lymphoma with and without Helicobacter pylori infection

BACKGROUND

The clinical features and clinical course of Helicobacter pylori-negative gastric mucosa-associated lymphoid tissue (MALT) lymphoma are unclear and a treatment strategy has not yet been established.

AIM

To clarify the clinical differences between H. pylori-positive and H. pylori-negative gastric MALT lymphoma, we compared these two types of gastric MALT lymphoma.

MATERIALS AND METHODS

Fifty-seven patients with localized gastric MALT lymphoma were studied. H. pylori infection was present in 41 and absent in 16. Treatment consisted of antibiotic therapy and/or 30 Gy radiation therapy. Response assessment was performed every 3-6 months by esophagogastroduodenoscopy including gathering biopsy samples, endoscopic ultrasonography, clinical examination, and various imaging procedures. The median follow-up period was 37 months.

RESULTS

There were no significant differences between H. pylori-positive and H. pylori-negative gastric MALT lymphoma patients in terms of sex, age, stage, gross phenotype, affected area of the stomach, or the presence of monoclonality. Complete regression was achieved with antibiotic therapy against H. pylori-negative gastric MALT lymphoma in one of nine patients (11.1%), compared to 28 of 38 patients (73.7%) with H. pylori-positive gastric MALT lymphoma (p < .001). Radiation therapy showed high effectiveness for the local control of H. pylori-negative or antibiotic-resistant gastric MALT lymphoma (92.9%), although distant recurrence was recognized in three of 14 patients (21.4%). Two of 16 patients (12.5%) with H. pylori-negative gastric MALT lymphoma died because of the transformation of the disease into diffuse large B-cell lymphoma. There was a significant difference in both the overall and cause-specific survival rate between the two groups (p = .038).

CONCLUSION

Radiation therapy is the effective treatment for H. pylori-negative or antibiotic-resistant localized gastric MALT lymphoma. However, careful systemic follow-up for distant involvement should be required. Transformation into diffuse large B-cell lymphoma is thought to be the important cause of death in patients with gastric MALT lymphoma.

The role of antigenic drive and tumor-infiltrating accessory cells in the pathogenesis of helicobacter-induced mucosa-associated lymphoid tissue lymphoma

Gastric B-cell lymphoma of mucosa-associated lymphoid tissue type is closely linked to chronic Helicobacter pylori infection. Most clinical and histopathological features of the tumor can be reproduced by prolonged Helicobacter infection of BALB/c mice. In this study, we have addressed the role of antigenic stimulation in the pathogenesis of the lymphoma by experimental infection with Helicobacter felis, followed by antibiotic eradication therapy and subsequent re-infection. Antimicrobial therapy was successful in 75% of mice and led to complete histological but not "molecular" tumor remission. Although lympho-epithelial lesions disappeared and most gastric lymphoid aggregates resolved, transcriptional profiling revealed the long-term mucosal persistence of residual B cells. Experimental re-introduction of Helicobacter led to very rapid recurrence of the lymphomas, which differed from the original lesions by higher proliferative indices and more aggressive behavior. Immunophenotyping of tumor cells revealed massive infiltration of lesions by CD4(+) T cells, which express CD 28, CD 69, and interleukin-4 but not interferon-gamma, suggesting that tumor B-cell proliferation was driven by Th 2-polarized, immunocompetent, and activated T cells. Tumors were also densely colonized by follicular dendritic cells, whose numbers were closely associated with and predictive of treatment outcome.

Molecular pathogenesis of mucosa-associated lymphoid tissue lymphoma

Extranodal marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue (MALT) type occur in a number of anatomic sites, but share overlapping morphologic and immunophenotypic features. Helicobacter pylori infection has been identified as an etiologic factor in gastric MALT lymphoma, and a growing list of other infectious organisms have recently been shown to be associated with MALT lymphomas at other anatomic sites. Although cause and effect has not been established for most of these infectious agents, our understanding of the biology has significantly improved, in part through the application of standard cytogenetic analyses. The common karyotypic alterations that characterize MALT lymphomas include the trisomies 3 and 18, the translocations t(11;18)(q21;q21), t(1;14)(p22;q32), t(14;18)(q32;q21), t(3;14)(q27;q32), and the recently described t(3;14)(p14.1;q32). This apparent complexity of cytogenetic alterations that have now been implicated in the pathogenesis of extranodal MALT lymphoma serves as a paradigm for molecular cross talk in neoplastic disease. Recent data have shown that at least three of the disparate translocations affect a common signaling mechanism, and thus unify all three under a common pathogenesis, resulting in the constitutive activation of the nuclear factor kappa B (NF-kappaB) pathway. It may be that the new MALT-related translocation involving the FOXP1 gene and other as yet undiscovered translocations may all have in common increased NF-kappaB signaling.

Detection of API2-MALT1 Fusion Transcripts in Cytologic Specimens of Patients with Pulmonary Mucosa-Associated Lymphoid Tissue Lymphoma

Mucosa-associated lymphoid tissue (MALT) lymphoma constitutes up to 90% of primary pulmonary lymphomas, but its diagnosis is often difficult. API2-MALT1 fusion is specific to MALT lymphoma and is detected in nearly half of the pulmonary cases. Cytologic examinations have played a pivotal role in the diagnosis of pulmonary tumors; however, cytologic specimens have only infrequently been used for molecular studies. In this study, we performed a multiplex reverse transcription-polymerase chain reaction (RT-PCR) assay to detect the API2-MALT1 fusion transcript in archival cytologic specimens used as RNA sources. We studied 3 pulmonary MALT lymphoma cases that were positive for the fusion gene as detected with RNA extracted from diagnostic histologic specimens. In 1 case, a conventional PCR clonality assay for the immunoglobulin heavy chain gene rearrangement failed to detect the monoclonality. In all 3 cases, the fusion transcript was successfully detected in the cytologic specimens of sputum, bronchoalveolar lavage fluid, bone marrow smears, and pleural effusions. This finding suggests that such specimens can be used as RNA sources in multiplex RT-PCR assays for the API2-MALT1 fusion transcript. The detection of API2-MALT1 fusion as carried out with these specimens would be useful as an ancillary assay for the diagnosis, staging, and follow-up of pulmonary MALT lymphoma.

Primary mucosa-associated lymphoid tissue (MALT) lymphoma of the larynx

BACKGROUND

Mucosa-associated lymphoid tissue (MALT) lymphoma is usually associated with a chronic inflammatory disease from which lymphoid tissue of MALT type arises as a prerequisite for lymphoma proliferation. No well-characterized chronic inflammatory process has been identified in the larynx.

METHODS

We report a case of primary MALT lymphoma of the larynx associated with extraesophageal reflux, chronic laryngitis, and gastric Helicobacter pylori infection, raising the issue of its physiopathology and treatment.

RESULTS

Treatment of this MALT lymphoma of the larynx consisted of complete surgical excision associated with omeprazole, amoxicillin, and clarithromycin. No evidence of disease was observed after 24 months of follow-up.

CONCLUSIONS

We may assume that chronic laryngitis could be a precursor to MALT lymphoma. This case is the first one to our knowledge of a primary MALT lymphoma of the larynx treated with conservative management combining surgical excision, reflux therapy, and eradication of gastric H. pylori infection.

Les lymphomes gastriques du MALT

INTRODUCTION

The stomach is the most common site involved in primary gastrointestinal lymphoma. Gastric lymphoma originates from the mucosa-associated lymphoïd tissue so called MALT. It comprises a group of distinctive clinicopathological entities which are important to consider for clinical management.

CURRENT KNOWLEDGE AND KEY POINTS

In recent years, new diagnostic tools and new treatment strategies have improved the overall prognosis. One of the most exciting recent discoveries is the hypothesis that an infection by a bacterium, Helicobacter pylori has a decisive role in gastric lymphoma.

FUTURE PROSPECTS AND PROJECTS

Recent advances, essentially due to molecular biology and cytogenetic studies may emerge with the understanding of pathogenesis and new prognostic factors of these different types of gastric lymphomas. It is the aim of our oncoming studies together with the evaluation of the new therapeutic options such as radiotherapy and monoclonal antibodies in prospective studies.

Atypical marginal zone hyperplasia of mucosa-associated lymphoid tissue: a reactive condition of childhood showing immunoglobulin lambda light-chain restriction

Mucosa-associated lymphoid tissue (MALT) lymphomas usually arise at sites of acquired MALT and are uncommon in native MALT (eg, Peyer patches and tonsil). Malignancy in these low-grade lymphomas is often inferred by immunoglobulin light-chain restriction and expression of CD43; molecular genetic evidence is sought only if these are in doubt. We report 6 cases (4 tonsils, 2 appendixes) of marginal zone (MZ) hyperplasia in children aged 3 to 11 years that, despite histologic and immunophenotypic features indicative of lymphoma, were polyclonal by molecular analysis. No lymphoma-directed therapy was given and patients remain alive and well (5 cases, median follow-up 35.3 months). The involved tonsil and appendix showed florid MZ hyperplasia with prominent intraepithelial B cells (IEBCs). The MZ B cells and IEBCs showed a high-proliferation fraction and a CD20(+), CD21(+), CD27(-), immunoglobulin (Ig) superfamily receptor translocation-associated 1-positive (IRTA-1(+)), CD43(+), multiple myeloma oncogene 1 (MUM-1), IgM(+)D(+) phenotype. Polymerase chain reaction (PCR), cloning, and sequencing of rearranged IgH and Iglambda genes (whole tissue sections [6 cases]; microdissected cells [2 cases]) showed that the MZ B cells and IEBCs were polyclonal and the IgH genes nonmutated. In contrast, MZ (intraepithelial) B cells of 6 control tonsils had a similar immunophenotype, except for expression of CD27 and polytypic light chains, whereas molecular studies showed that they were polyclonal with mutated Ig genes.

Heterogeneous copy numbers of API2-MALT1 chimeric transcripts in mucosa-associated lymphoid tissue lymphoma

T(11;18)(q21;q21) results in a chimeric transcript between API2 at 11q21 and MALT1 at 18q21 and is a characteristic chromosomal aberration of extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma). API2-MALT1 chimeric transcripts are present in approximately one-third of all cases of MALT lymphoma. MALT lymphoma is also known to have variations in histological features and tumor cell proportions. Real-time polymerase chain reaction (PCR) was used to examine number of API2-MALT1 copies in clinical samples for further investigation of the pathophysiology of MALT lymphoma. A total of 13 samples of MALT lymphoma contained API2-MALT1 transcripts from 1.7 x 10(-2) to 1.0 copies/beta-actin copy. These findings were compared to the proportions of tumor cells in genomic VDJ PCR products determined by Southern blotting. Tumor cell ratios varied widely among the patients' samples, and no significant correlation was found between transcript copy number and tumor cell ratio. These results suggest that copy numbers of API2-MALT1 do not reflect tumor cell proportions, and that the number of copies of API2-MALT1 in a tumor cell is different for each clinical sample.

Pre- and postsurgical biomagnetic activity in malt-type gastric lesions. A case report

PURPOSE

To evaluate the biomagnetic activity of a low-grade mucosa-associated lymphoid tissue (MALT-) type gastric lymphoma, and to determine if this procedure could be an adjunct to endoscopic ultrasonography (EUS) in the assessment of the disease pre- and postsurgically.

MATERIAL AND METHODS

A 47-year-old female with a 2-year clinical history of a low-grade MALT-type gastric lymphoma associated with Helicobacter pylori was examined. The disease showed no histologic remission after eradication of the H. pylori infection and subsequent treatment with chemotherapy and the patient was classified as stage II EA. A decision for surgical resection was made. Biomagnetic waveform recordings were made in the target area before and after surgery and the Fourier analysis of these recordings was performed.

RESULTS

The gastric lymphoma biomagnetic waveforms showed high amplitudes (1.8 pT) before and low amplitudes (0.6 pT) after resection. The corresponding Fourier analysis demonstrated that the maximum spectral power of the presurgical measurement was elevated (mean 235 +/- 847 pT2/Hz) compared with that obtained postsurgically (mean 725 +/- 89 pT2/Hz). The difference was of statistical significance ( p < 0.0001, t-test).

CONCLUSION

Biomagnetic monitoring of gastric lymphoma, which is an entirely new diagnostic modality, could be a supplement to EUS for assessing remission or persistence of disease with medical treatment during follow up.

Region-specific immunological response of the different laryngeal compartments: significance of larynx-associated lymphoid tissue

The occurrence of primary extranodal marginal-zone B-cell lymphoma [of the mucosa-associated lymphoid tissue (MALT) type] has only been described in the supraglottic region, implying that preexistent organized lymphoid tissue is present at that site only. To date, studies have not established clearly whether organized MALT shows a site-related distribution in the larynx. The supraglottic region of the false vocal folds and the subglottis from 87 unselected cadavers with no known history of nasal, oral, pharyngeal, laryngeal, tracheal, or esophageal disease were examined for the presence of organized MALT. Organized lymphoid tissue was found with the cytomorphological and immunophenotypic features of MALT in 100% of false vocal folds of children and in more than 90% of adolescents, decreasing to 7.1% in persons in their sixth decade, whereas MALT was completely absent in the subglottis in all age groups. The results explain why primary extranodal marginal-zone B-cell lymphoma has only been described in the supraglottic region but is absent in the subglottis. Moreover, the results suggest a region-specific immunological response of the different laryngeal areas as reflected in clinical observations and animal studies. However, the impact on presence or absence of laryngeal MALT awaits clarification.

Consecutive regression of concurrent laryngeal and gastric MALT lymphoma after anti-Helicobacter pylori therapy

The most common primary lymphoma of the gastrointestinal tract is B-cell lymphoma arising from mucosa-associated lymphoid tissue known as MALT lymphoma. Although the majority of these lesions affect the stomach and are associated with Helicobacter pylori organisms, sites other than the gastrointestinal tract may be affected. This case report describes a patient with concomitant laryngeal MALT lymphoma and Helicobacter pylori-related gastric MALT lymphoma derived from the same clone as confirmed by PCR. Treatment of Helicobacter pylori infection in this patient using antibiotics led to regression of both lesions. This patient remains in remission at 46-month follow-up. This is the first case report on the regression of a laryngeal MALT lymphoma after Helicobacter pylori eradication. We suggest that all patients presenting with extragastric MALT lymphoma should undergo upper gastrointestinal endoscopy with gastric biopsies for the determination of Helicobacter pylori status and presence of concomitant gastric MALT lymphoma, followed by a course of anti-Helicobacter pylori antibiotic therapy. Nonresponders may subsequently be considered for surgery and/or chemo/radiation therapy.

Pulmonary low-grade MALT-lymphoma associated with localized pulmonary amyloidosis. A case report

We report on a female patient, who, at the age of 63 years, was found to suffer from low-grade MALT-lymphoma localized at her right upper eyelid. At the time of initial diagnosis, clinical staging showed no further organ involvement. Within the following two months, nodular infiltrates occurred in both lungs. Histopathological investigation of the pulmonary lesions showed pulmonary involvement by the low-grade MALT-lymphoma associated with large globular amyloid deposits of lambda-light chain origin. Since the tumor cells of the MALT-lymphoma showed restriction to lambda-light chain the amyloid deposits in this case were interpreted as being related to the MALT-lymphoma.

[Helicobacter pylori and malignant diseases of the stomach]

The association between Helicobacter pylori infection and gastric malignancies, cancer and MALT lymphoma, has been suggested through several lines of evidence during the last decade. Although unresolved issues still cast doubts on the real weight of these association, in the sequence of events that leads to gastric cancer or lymphoma, Helicobacter pylori appears to play a prominent role in the very initial steps as causative agent of chronic gastritis. The subsequent events in the sequence--atrophy, intestinal metaplasia, dysplasia and cancer are multifactorial involving environmental agents, host response and characteristics of the bacterial strain itself. Recognition of the causal role of Helicobacter pylori infection in the cancer induction theoretically presents tools for its prevention. The ongoing studies will show in the future whether eradication or prevention of infection are followed by a reduction in risk of cancer. Lymphomas arising from gastric mucosa-associated lymphoid tissue (MALT) may be a clonal evolution starting from the infection. In low-grade gastric MALT lymphoma cure of the infection induces complete remission in the majority of patients. Longer follow-up investigations are necessary to determine if remissions indicate a cure of the disease.

MALT lymphoma of the intestine. A clinicopathological study over a period of 13 years

Clinicopathological features of 14 patients with histologically confirmed primary intestinal Non-Hodgkin lymphoma were analysed. Patients were mostly young males with median age of 27.2 years. Main presenting features was intestinal obstruction. Diffuse large cell lymphoma was the commonest histological type. All cases were found to be B cell type in immunohistochemistry.

Regression of gastric mucosa-associated lymphoid tissue lymphoma with reduced telomerase activity after eradication of Helicobacter pylori

Recently, telomerase activity has been demonstrated in a large number of malignant tumors whereas its activity is not detected in most normal somatic cells suggesting its role in the immortalization process. Here we report the first investigation of telomerase activity in a case of gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Elevated telomerase activity was detected in biopsy specimens of the lymphoma. After eradication of Helicobacter pylori, the level of telomerase activity returned to normal with histological regression of the lymphoma. The telomerase activity was associated with the disease activity of the gastric MALT lymphoma after eradication therapy in the present case.

Genetic abnormalities in marginal zone B-cell lymphoma

Marginal zone B-cell lymphoma (MZBCL) including extranodal mucosa-associated lymphoid tissue (MALT)-type lymphoma, nodal, and splenic MZBCL represents a distinct subtype of B-non-Hodgkin's lymphoma. Recently, important progress in the elucidation of the genetic mechanisms underlying the pathogenesis and disease progression of these lymphomas has been made. The API2 gene, an inhibitor of apoptosis, and the novel MLT gene have been found to be altered by the t(11;18)(q21;21), which represents the most frequent structural chromosomal abnormality in extranodal low-grade MALT lymphoma. Another gene involved in the regulation of apoptosis, the BCL10 gene, has been cloned from a MALT lymphoma cytogenetically characterized by the t(1;14)(p22;q32). Along the same lines, inactivating mutations of the proapoptotic FAS gene have been detected in a relatively high proportion of extranodal MZBCLs. Considering these data and the fact that at least some MALT lymphomas show low levels of apoptosis and seem to escape from FAS-mediated apoptosis one may speculate that abrogation of apoptosis constitutes a central pathogenetic mechanism in the development of these lymphomas. The pathogenetic role of trisomy 3, the most frequent numerical chromosomal change of MZBCL, is not known. The minimal overrepresented region has been delineated to 3q21-23 and 3q25-29 using comparative genomic hybridization. The BCL6 proto-oncogene, located on 3q27, which is rearranged in some MZBCL and a high proportion of large cell B-cell lymphomas with extranodal localization, represents one of the candidate genes residing in these critical regions.

Gastric MALT lymphoma: from concept to cure

Gastric MALT lymphomas are clinically and histologically quite distinct from comparable low-grade B-cell lymphomas of lymph nodes. Their histology suggests that immunological mechanisms might be operative in their growth. Given that there is normally no lymphoid tissue in gastric mucosa and that Helicobacter pylori (H. pylori), the only common bacterial antigen in the stomach, results in the accumulation of gastric MALT, the possibility that this organism is implicated in the pathogenesis of gastric lymphoma has been extensively investigated. It appears that most, but not necessarily all, gastric MALT lymphomas arise in MALT acquired in response to H. pylori infection and develop by stepwise accumulation of genetic abnormalities. Early molecular events in the evolution of gastric MALT lymphoma from 'acquired' MALT include trisomy 3, t(11;18)(q21;q21), genetic damage leading to genetic instability, as indicated by the so-called replication error repair (RER) phenotype, and both p53 and c-myc mutations. At this stage in their development, the growth of the lymphomas is driven by contact between the neoplastic B cells and H. pylori specific intra-tumoral T cells. Eradication of H. pylori causes the tumour to enter a latent phase resulting in clinical regression. Later events, such as t(1;14)(p22;q32), appear to be linked to a capacity for autonomous growth, loss of sensitivity to H. pylori and dissemination of the lymphoma beyond the stomach and gastric lymph nodes. Cloning of the breakpoint in t(1;14) has allowed the identification of a new tumour suppresser gene, bc110. High grade transformation of MALT lymphoma has been associated with p53 inactivation, deletions of p16 and t(8;14).

Mucosa-associated lymphoid tissue lymphoma

A distinctive type of low-grade extranodal lymphoma recapitulates the cytomorphologic features of mucosa-associated lymphoid tissue (MALT). Typically, these MALT lymphomas arise from sites normally devoid of lymphoid tissue, but are preceded by chronic inflammatory, usually autoimmune, disorders that result in the accumulation of lymphoid tissue. The stomach is the most common site of MALT lymphoma, which arises from lymphoid tissue acquired as the result of Helicobacter pylori infection. The indolent clinical behavior of gastric MALT lymphoma coupled with certain histologic features suggests that its growth is subject to immunologic stimuli, and the role of H pylori in this respect has been examined in detail. In vitro experiments have shown that the growth of lymphoma cells is stimulated by contact with T cells, which, in turn, show strain specific responses to heat-killed H pylori. Clinically, approximately 70% of cases of stage IE gastric MALT lymphoma regress following eradication of H pylori with antibiotics. Large, deeply invasive tumors and those that have undergone high-grade transformation typically do not respond to antibiotic therapy. Other common sites of MALT lymphoma include the salivary glands, lung, and ocular adnexa. The clinicopathologic features of these lymphomas are remarkably similar to gastric MALT lymphoma, which suggests that they, too, may be antigen-driven.

Primary lymphomas of the thyroid gland: a review with emphasis on diagnostic features

The information about primary lymphomas of the thyroid--a rare form of thyroid tumor and a rare form of lymphoma as well--is dispersed in numerous scientific publications. Recent developments in the field of lymphoid neoplasias, in particular the recognition of mucosa-associated lymphoid tissue (MALT) and the characterization of its distinctive type of lymphomas, has drawn new attention to primary lymphomas of the thyroid and has provided new insights into this field of thyroid pathology. In this paper we review the pathogenesis and the clinicopathologic features of primary lymphomas of the thyroid, we discuss the diagnostic basis and the strategies for differential diagnosis, and we address some recent data that may provide additional pathways to further our understanding of those rare thyroid diseases.

Lymphoid complement of the human salivary glands: function and pathology

In normal human salivary glands the Duct-Associated Lymphoid Tissue (DALT) is poorly developed. In contrast, in the course of autoimmune disorders, typified by Sjögren's syndrome (SS), organized lymphoid accumulations are formed around the ducts. B cell-dependent zones with secondary follicles and T cell-dependent zones with HEV are detected in these lymphoid structures. In addition, the duct epithelium is infiltrated by abundant lymphocytes. A persistent antigenic stimulation may lead to development of B-cell Mucosa-Associated Lymphoid Tissue (MALT) lymphomas that, in low-grade cases, maintain the lobular organization of normal and of SS salivary glands.

Successful treatment of IgA nephropathy in association with low-grade B-cell lymphoma of the mucosa-associated lymphoid tissue type

Kidney and the urogenital tract are among the various mucosal sites involved in mucosa-associated lymphoid tissue (MALT) lymphoma. We report a case with simultaneous onset of crescentic immunoglobulin (Ig) A nephropathy and gastrointestinal low-grade B-cell lymphoma of the MALT type with kidney infiltration. M-component of IgM lambda was detected in the serum, and the renal biopsy specimen showed monotypic lambda light chain staining in the lymphoma cells but not the glomeruli. The heavy proteinuria and impaired creatinine clearance returned to normal, and microscopic hematuria disappeared 20 months after treatment with chlorambucil as single-agent chemotherapy. This coincided with a complete resolution of the gastric and renal lymphoma infiltration. The close association of both the onset and successful outcome of the two entities thus support their possible causal relationship, and we discuss the possibility of an association of the disturbance of the MALT by the lymphoma cells with the pathogenesis of IgA nephropathy.

Recent advances in our understanding of the biology and pathogenesis of gastric mucosa-associated lymphoid tissue (malt) lymphoma

The evolution of gastric mucosa-associated lymphoid tissue (MALT) lymphoma is a multi-stage process, comprising the sequential development of chronic H. pylori-associated gastritis, low grade and high grade lymphoma. The genesis of MALT lymphoma embodies the mechanisms of both physiological immune responses and the acquisition of genetic abnormalities. The tumour probably originates from an autoreactive MALT marginal zone B cell, which is generated during H. pylori infection. As a consequence of a genotoxic insult induced by H. pylori infection, the progenitor tumour cell may become genetically unstable and develop genetic abnormalities such as the t(11;18) translocation, trisomy three, c-myc and p53 mutations during a phase of expansion, which lead to partial transformation. With the growth help from H. pylori specific T cells, this abnormal B cell clone may undergo clonal expansion and gradually form a low grade MALT lymphoma. Additional genetic abnormalities including the t(1;14) translocation and other uncharacterised events could completely transform this abnormal B cell clone and result in escape from T cell dependency. Finally, further genetic events such as complete inactivation of the tumour suppressor genes p53 and p16, and possible activation of c-myc oncogene by translocation or other undetermined abnormalities can result in high grade transformation

Mucosa-associated lymphoid tissue gastrointestinal and nongastrointestinal lymphoma behavior: analysis of 108 patients

PURPOSE

Characteristics and outcome of 108 patients with mucosa-associated lymphoid tissue (MALT) lymphoma were analyzed according to initial location of the lymphoma, within or outside of the gastrointestinal (GI) tract.

PATIENTS AND METHODS

One hundred eight patients with MALT lymphoma were studied. Fifty-five patients (51%) had GI involvement and 53 patients (49%) had another involved extranodal site: 13 orbit; 11 lung; 10 skin; seven parotid; six thyroid; three Waldeyer's ring; two breast; and one pancreas involvement. At diagnosis, 47 patients (44%) had stage IE, 26 (24%) had stage IIE, and 35 (32%) had disseminated disease. No significant difference in the clinical or biologic characteristics was observed between GI and non-GI patients.

RESULTS

Complete response after the first treatment was reached in 76% of the patients, with no difference between the two subgroups. With a median follow-up of 52 months, median survival was not reached and was identical in the two subgroups, but GI MALT patients had a longer time to progression (8.9 years compared with 4.9 years in non-GI patients; P = .01). The different non-GI locations seemed to have a similar outcome.

CONCLUSION

MALT lymphoma is an indolent disease that usually presents as localized extranodal tumor without accompanying adverse prognostic factor, and these patients have a good outcome. However, non-GI patients seem to progress more often than GI patients.

Helicobacter pylori, gastric MALT and B-cell clonality

MALT, or mucosa associated lymphoid tissue, is normally not present in gastric tissue. Its presence is often associated with persistent antigenic stimulation. MALT is a precursor of gastric MALT lymphoma, a low-grade lymphoma whose incidence recently appears to have increased. Although much epidemiologic and clinical evidence has linked both MALT and MALT lymphoma to Helicobacter pylori infection, it is not known whether other agents and or mechanisms may also play a role and whether there is a clearly defined pre-neoplastic lesion. In particular, the clinical significance of B-cell clonality remains unknown. In a recent study we attempted to define the role of H. pylori and MALT in the genesis of B-cell clonality in a northern Italian patient population referred to us for simple dyspepsia. The results show that B-cell clonality is unexpectedly frequent in these patients regardless of the presence of H. pylori infection. These observations raise the possibility that agents and mechanisms other than H. pylori may be involved in the genesis of MALT lymphoma. Indeed, other studies conducted by our group in patients with Sjögren's syndrome indicate that genetic/immunologic factors and possibly viruses may play a role. The high prevalence of B-cell clonality in an otherwise healthy population suggests either that most of these patients are at risk of developing MALT lymphoma (in which case this condition at the moment may be greatly underdiagnosed) or that B-cell clonality is a very early step in the development of neoplasia, which requires several other factors and which will occur only in a restricted fraction of these patients. Careful follow-up studies will provide an answer to this question.

Mucosa-associated lymphoid tissue lymphomas

Mucosa-associated lymphoid tissue (MALT) lymphomas are a distinct subgroup of non-Hodgkin's lymphoma with a particular clinicopathologic behavior. The gastrointestinal tract is involved in two thirds of the cases, but it may be observed in lung, breast, bladder, conjunctiva, kidney, liver, skin, salivary glands, thyroid, and thymus. This type of lymphoma tends to appear in patients with a history of autoimmune disease or chronic inflammatory disorders. In the stomach, this lesion is induced by Helicobacter pylori and is characterized by an accumulation of lymphoid tissue leading to chronic gastritis. The preceding lymphoid disorder is represented by Sjögren's syndrome, Hashimoto thyroiditis, and interstitial lymphoid pneumonia in the thyroid, salivary glands, or lung, respectively. Lymphoma cells initially arise from the marginal zone localized around reactive follicles and secondarily invade epithelial tissue to form the characteristic lymphoepithelial lesion. Patients with gastrointestinal MALT lymphoma generally present with localized disease without any adverse prognostic factors. These patients have long survival rates. Recurrences may appear in the same organ or in other extranodal sites. Nongastrointestinal MALT lymphoma patients seem to have a similar outcome. Patients may be treated with surgery or radiotherapy if the disease is localized, or with single-agent chemotherapy if it is disseminated. Reversion of the chronic inflammatory disorder with antibiotics, such as for gastric involvement, is a new observation that may change therapeutic options in the future.

Primary malignant lymphoma of the intestine: clinicopathologic and immunohistochemical studies of 39 cases

Clinicopathologic and immunohistochemical features in 39 cases of primary intestinal non-Hodgkin's lymphoma (NHL) in Japanese patients were studied. Only resection materials in state IE and IIE-1 were included in this study because of the certainty that the intestine was the primary site of the lymphoma. The updated Kiel classification was used to classify NHL. Histologically, only two cases (5.1%) were follicular lymphomas, and the others were diffuse lymphomas. Twenty-eight patients (71.8%) had high-grade NHL and 11 (28.2%) had low-grade NHL. Twenty (71.4%) of the 28 high-grade NHL were centroblastic lymphomas, and 14 (70.0%) of these 20 cases of centroblastic lymphoma were the polymorphic variant. Ten (90.9%) of the 11 low-grade NHL were low-grade mucosa-associated lymphoid tissue (MALT) lymphomas. Macroscopically, 18 patients had polypoid masses, 17 ulcerative tumors and four had diffusely infiltrating NHL. Seven of the 10 low-grade MALT lymphomas were polypoid masses. Immunohistochemically, 35 lesions (89.7%) were of the B cell phenotype and three (7.7%) were of the T cell phenotype. In the remaining case, the cell lineage could not be determined. No lesions were considered to be of histiocytic origin. The 5 year survival rate for high-grade B cell lymphomas was poorer than for low-grade B cell lymphomas, and the present study indicated that the histological grade of the intestinal B cell lymphomas was a prognostically significant factor.