B-cell lymphoma of MALT type: a review with special emphasis on diagnostic and management problems of low-grade gastric tumours

A Rare Case of Primary Extra-Nodal Marginal Zone Lymphoma of Mucosa-Associated Lymphoid Tissue (MALT) in the Rectum

Mucosa-associated lymphoid tissue (MALT) is a unique clinical condition that can manifest in different anatomic locations. In the gastrointestinal tract, it is typically seen in the stomach but is less commonly found in other sites. There have been a few cases in the literature in which primary MALT lymphoma is found in the rectum. We describe a case of a 63-year-old male who presented with rectal pain and bleeding. Colonoscopy revealed a rectal mass, which was excised with a trans-anal approach. Histopathological examination of the biopsy specimen was significant for MALT lymphoma. Therefore, the patient underwent radiation therapy followed by repeat colonoscopies to monitor disease recurrence.

An unusual presentation of gastric mucosa-associated lymphoid tissue (MALT) lymphoma following blunt abdominal trauma

A 79-year-old woman presented to the emergency department following a motor vehicle collision. As part of her workup she underwent a CT scan which identified a large mass containing calcifications centred around the gastric antrum, and while being assessed she produced 500 mL of haematemesis. An endoscopy revealed an area of friable mucosa the nature of which was uncertain, and multiple biopsies revealed amyloid deposition and active Helicobacter pylori gastritis. Following review of imaging and pathology, a diagnosis of gastric mucosa-associated lymphoid tissue (MALT) lymphoma was established. She was treated with quadruple therapy for the H. pylori and at 6-month follow-up she is asymptomatic with repeat endoscopy revealing healing of the ulceration and no biopsy evidence of H. pylori or MALT.

Primary Gastric Lymphoma, Epidemiology, Clinical Diagnosis, and Treatment

Primary gastric lymphoma (PGL) is the most common extranodal non-Hodgkin lymphoma and represents a wide spectrum of disease, ranging from indolent low-grade marginal zone lymphoma or mucosa-associated lymphoid tissue (MALT) lymphoma to aggressive diffuse large B-cell lymphoma. The PGL is a relatively rare cancer and easily misdiagnosed due to its unspecific symptoms of the digestive tract. The medical literature and ongoing clinical trials were reviewed on the clinical presentation, diagnosis, prognosis, prevention, and treatment of PGL. Primary gastric lymphoma is an event in the course of cancer with a variable clinical presentation and a wide differential diagnosis. Chronic gastritis secondary to Helicobacter pylori (H pylori) infection has been considered a major predisposing factor for MALT lymphoma. Magnetic resonance imaging and endoscopic ultrasonography have helped in staging of these cancers. The clinical course and prognosis of this disease are dependent on histopathological subtype and stage at the time of diagnosis. A global therapeutic approach to the cure of PGL has completely changed over the past 10 years, including innovative and conservative options to reduce treatment toxicity. Due to the rarity of PGL, many aspects of this neoplasm are still controversial. The incidence of this disease is increasing, making it necessary for clinicians to understand the clinical symptoms, workup, and treatment of these lymphomas.

Primary mucosa-associated lymphoid tissue lymphoma of the thyroid with concomitant papillary carcinoma

Objective

Papillary thyroid carcinoma combined with thyroid mucosa-associated lymphoid tissue (MALT) lymphoma is exceedingly rare and there is no standard management.

Case report

We report a rare association of MALT lymphoma of thyroid in a 60-year-old woman with Hashimoto's thyroiditis along with an incidental focus of papillary carcinoma.

Conclusion

Patients with Hashimoto's thyroiditis are prone to develop other thyroid pathology, including rare tumours such as MALT lymphoma. The differential diagnosis for a neoplasm in such patients should be wide.

Marginal zone lymphomas and infectious agents

A link with infectious agents, bacteria and viruses in particular, has been reported for many lymphoma entities. Marginal zone lymphomas (extranodal, nodal and splenic forms) are frequently associated with chronic infections, with important clinical, molecular, biological, and therapeutic implications. The well-known correlation between Helicobacter pylori and gastric MALT-lymphoma, the recently reported links between Chlamydophila psittaci and ocular adnexal MALT-lymphoma and Borrelia burgdorferi and cutaneous MALT lymphoma constitute the best studied examples of lymphomagenic activity of bacteria, while the hepatitis C virus represents the most extensively investigated virus associated with marginal zone lymphomas. Biological and clinical features, therapeutic implications and future perspectives of these lymphoma-microbial associations are discussed in this review.

Two tracheal BALT lymphoma patients successfully treated with chemotherapy including rituximab

Bronchus-associated lymphoid tissue (BALT) lymphoma of the trachea, an important differential diagnosis for tracheal tumors, is a rare disease with characteristic bronchoscopic findings. In this study, we reviewed 2 cases of patients who were symptomatic at the time of diagnosis, with tumors in the trachea and left main bronchus, putting them at high risk for asphyxia. Chemotherapies including rituximab were administered, and complete remission was confirmed in both cases. Because tracheal tumors often have a pernicious course, it might be beneficial to initiate a chemotherapeutic treatment regimen instead of adopting the "wait-and-see" approach in patients with symptomatic tracheal BALT lymphoma.

Hepatic dysfunction after radiotherapy for primary gastric lymphoma

Patients with primary gastric lymphoma (PGL) are often treated with three-dimensional conformal radiotherapy (3D-CRT) in three to four fields to reduce the dose to the left kidney. However, the liver dose is higher than conventional parallel-opposed fields. This study was designed to evaluate hepatic dysfunction after 3D-CRT in patients with PGL. The data of 20 PGL patients treated with 3D-CRT were analyzed. Of the 20 patients, 3 had mucosa-associated lymphoid tissue (MALT) lymphoma and 17 had diffuse large B-cell lymphoma (DLBCL). The median dose used to treat MALT lymphoma was 30 Gy and 40 Gy for DLBCL. Pretreatment and post-treatment transaminase and alkaline phosphatase (ALP) values were compared. Radiation-induced hepatic dysfunction (RIHD) was defined as a more than 2-fold increase in transaminase or ALP levels, exceeding the upper limit within 4 months of the completion of radiotherapy. Increased transaminase or ALP levels were observed in 19 patients (95%). RIHD was observed in 14 patients (70%). The transaminase and ALP values were significantly different between pretreatment and post-treatment. There were significant differences in liver volumes receiving ≥5, ≥10, ≥15 and ≥20 Gy (V5, V10, V15 and V20) and in the mean liver doses between patients with and without RIHD. For patients with V10 > 60%, V15 > 50% or V20 > 30% in particular, the incidence rates of RIHD were significantly high. After radiotherapy for PGL, hepatic dysfunction occurred at a high rate. Thus, radiotherapy treatment should be planned in order to reduce liver doses.

Clinical challenges of primary diffuse large B-cell lymphoma of the dura: case report and literature review

Primary dural lymphoma is a rare disease with more indolent clinical behavior compared to primary central nervous system lymphoma. The majority of the reported cases were indolent marginal zone lymphoma subtype with more predilections to the spine. Herein, we are presenting a case of intracranial, diffuse large B-cell lymphoma of the dura that was diagnosed and treated at our institution. We are presenting the challenges in the treatment based on a review of the literature.

Pulmonary BALT lymphoma successfully treated with eight cycles weekly rituximab: report of first case and F-18 FDG PET/CT images

Extra marginal-zone lymphomas of the lung is a very rare tumor and it originates from bronchial-associated lymphoid tissue. A 68-yr-old woman presented with productive cough and dyspnea. A thorax computed tomography scan showed a 9 × 10 cm in size mass in the left lung and pleural effusion in the lower lobe of left lung. Positron emission tomography/computed tomography (PET/CT) revealed intense uptake foci at the upper and middle sites of left lung and slight uptake foci at the mediastinal lymph nodes which showed malignant involvement. After bronchoscopic biopsy, the diagnosis of pulmonary bronchial-associated lymphoid tissue (BALT) lymphoma was confirmed. At the end of the eight cycles weekly rituximab treatment, complete response was obtained by PET/CT findings. It is concluded that extended rituximab schedule is more effective and it would be beneficial to investigate the use of PET/CT in the diagnosis and evaluating of the treatment response of pulmonary BALT lymphoma.

NF-κB as a potential therapeutic target in myelodysplastic syndromes and acute myeloid leukemia

IMPORTANCE OF THE FIELD

The inactive NF-κB-inhibitor of NF-κB (IκB) complex is activated by stimuli including pro-inflammatory cytokines, mitogens, growth factors and stress-inducing agents. The release of NF-κB facilitates its translocation to the nucleus, where it promotes cell survival by initiating transcription of genes encoding stress-response enzymes, cell-adhesion molecules, pro-inflammatory cytokines and anti-apoptotic proteins. NF-κB and associated regulatory factors (IκB kinase subunits and bcl-3) are implicated in hematological and solid tumour malignancies. NF-κB appears to be involved in cell proliferation control, apoptosis control, angiogenesis promotion and possibly regulation of diffusion of metastases. There are several reports that inhibition of NF-κB as a therapeutic target may have a role in tumour cell death or growth inhibition.

AREA COVERED IN THIS REVIEW

We review data about inhibition of NF-κB in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). We describe the molecular mechanisms underlying NF-κB deregulation in these haematological malignancies.

WHAT THE READER WILL GAIN

Constitutive activation of NF-κB in the nucleus has been reported in some varieties of MDS/AML. The in vitro and in vivo results of NF-κB inhibition in myeloid malignancies are highlighted.

TAKE HOME MESSAGE

NF-κB selective inhibitory drugs may be useful, either as single agents or associated with conventional chemotherapy.

MALT lymphoma of the rectum, presenting with rectal prolapsus: a case report

Up to now, there have been only a few reported cases of Mucosa-associated lymphoid tissue (MALT) lymphomas arising in the rectum. Its clinical presentation is indistinguishable from that of rectal carcinoma but the treatment is apparently different. Symptoms of primary lymphomas involving the rectum include; anorexia, weight loss, change in bowel habits, obstruction, and bleeding. These symptoms are not disease specific and can be seen in many other gastrointestinal disorders. Patients with polypoid masses may present with obstruction symptoms. In this rare case, a female patient admitted to the emergency service with prolapsus of a rectal mass.

The optimal treatment of rectal MALT lymphoma is not well defined yet, given the rarity of the disease. Surgical resection of the localized lesion and following adjuvant chemotherapy has proved to be an effective treatment option. However, a close and long-lasting follow-up is important.

Early-stage gastric MALT lymphoma: is it a truly localized disease?

Early-stage gastric mucosa-associated lymphoid tissue lymphoma (GML) is considered a localized disease with an indolent course. Circulating malignant cells have been detected in other early-stage indolent lymphomas by molecular methods. We investigated the incidence of occult blood disease in early-stage GML patients, its impact on clinical outcome, and the similarity between blood and gastric lymphocytic clones. Sixty-two patients with localized GML were included in the study; 51 of them had Helicobacter pylori infection. Monoclonality was investigated by leader polymerase chain reaction. Sequencing was performed for the immunoglobulin variable gene (VH) analysis. Blood involvement was absent in all patients by conventional staging methods. In the whole group of 62 patients, the incidence of blood IgH rearrangement was 45%, and this did not correlate with baseline patient characteristics. The monoclonal blood and gastric products of five patients were sequenced and compared with each other. Clonal identity was evident in four of five patients. The VH3 gene was the most frequently used, both in the blood and in the stomach. Early-stage GML is not a truly localized disease because half the patients had a circulating clone, probably identical to the gastric one. The clinical significance of occult blood disease and the potential appropriate intervention need to be further investigated.

Presence of a high-grade component in gastric mucosa-associated lymphoid tissue (MALT) lymphoma is not associated with an adverse prognosis

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma and diffuse large B cell lymphoma (DLBCL) show a spectrum of disease characterized by varying proportions of low-grade and high-grade components. While the natural history and optimum treatment for low-grade gastric MALT lymphoma and DLBCL is well established, the prognosis and optimal treatment of patients with both low- and high-grade components is not well established. The purpose of our study was to evaluate the clinical characteristics, survival outcomes, and prognostic factors of patients with gastric MALT lymphoma and gastric DLBCL. A retrospective review of patients with gastric MALT lymphoma, gastric DLBCL, or MALT lymphoma with a high-grade component treated at our centers from 1994 to 2006 was performed. Patients were divided into three categories: "pure MALT lymphoma," "MALT lymphoma with high-grade component" (mixed), and "pure DLBCL." Seventy-six patients were included in our study-26 with pure MALT, 22 with MALT with high-grade component ("mixed"), and 28 with pure DLBCL. Pure MALT lymphoma and mixed lymphoma patients had similar clinical characteristics, whereas pure DLBCL patients had less favorable disease characteristics with significantly poorer performance status, higher number of extranodal sites of disease, higher stage, and larger proportion of bone marrow involvement and international prognostic index (IPI) scores compared with mixed lymphoma. The majority of mixed lymphoma (72.7%) and DLBCL patients (71.4%) were treated with chemotherapy. Of patients receiving chemotherapy, a higher proportion of mixed lymphoma and DLBCL patients received anthracycline-based combination chemotherapy regimens compared with MALT lymphoma (73% vs 71% vs 8%) whereas the proportion of mixed lymphoma and DLBCL patients was similar (p = 0.919). At a median follow-up of 37 months, the 5-year overall survival was 66.9%. The 5-year overall survival was 78% for MALT lymphoma, 84% for mixed lymphoma, and 45% for DLBCL. On univariate analysis, DLBCL histology, age, performance status, serum albumin, lactate dehydrogenase, bone marrow, number of extranodal sites, stage, and IPI score were prognostic for inferior survival. On multivariate analysis, DLBCL histology remained significantly prognostic for inferior survival, independent of chemotherapy regimen (hazard ratio (HR) 6.66, 95% confidence interval (CI) 2.01-21.41, p = 0.001). Mixed histology was not prognostic for inferior survival (HR 1.13, 95% CI 0.28-4.54, p = 0.868). Other factors prognostic for inferior survival were serum albumin <37 g/L (HR 3.22, 95% CI 1.11-13.22, p = 0.034) and treatment with non-cyclophosphamide, doxorubicin, vincristine, and prednisolone chemotherapy (HR 4.89, 95% CI 1.67-14.36, p = 0.004). In conclusion, the clinical characteristics of mixed histology MALT lymphoma are similar to low-grade MALT lymphoma and significantly different from pure DLBCL. The prognosis of mixed histology MALT lymphoma is significantly better than pure DLBCL, independent of IPI and chemotherapy regimen, and pure DLBCL histology is independently prognostic of inferior survival outcome.

Radiotherapy for 41 patients with stages I and II MALT lymphoma: a retrospective study

PURPOSE

Mucosa-associated lymphoid tissue (MALT) lymphoma is a distinct disease with specific clinical and pathologic features that may affect diverse organs. We analyzed our recent experience with Stage I/II MALT lymphoma presenting in the stomach and other organs to assess the outcome following radiation therapy (RT) alone.

PATIENTS AND METHODS

Forty-one patients with Stages I (37) and II (4) disease were treated between 2000 and 2006. Patients with transformed MALT were excluded. The median age was 60 years (range, 25-86 years), male: female ratio 1:1. Presenting sites included stomach, 11; orbital adnexa, 21; thyroid, 1; other head and neck, 3; small bowel, 3; skin, 1; and rectum, 1. Thirty-five patients (85%) received RT-alone and 6 (15%) received antibiotics followed by RT. RT dose was 30Gy in 20 fractions (fr) in all 41 patients. Mean follow-up time was 32.0 months (range, 2.1-162 months).

RESULTS

A first complete response was achieved in all 41 patients. Only one patient died from bile duct carcinoma at 22 months from the start of irradiation for conjunctiva MALT lymphoma without recurrence of lymphoma. The other 40 patients were alive. Thirty-eight patients out of them were alive without recurrence. One patient with a duodenal lymphoma had a recurrence in non-irradiated distant sites at 1 month. Another patient with a bilateral eye lid lymphoma had a recurrence within radiation field at 41 months. The absolute local control rate with radiation was 98% (40/41 patients).

CONCLUSION

Localized MALT lymphomas have excellent prognosis following moderate-dose RT (30Gy/20fr).

Long-term follow-up of gastrectomized patients with mucosa-associated lymphoid tissue lymphoma: need for a revisit of surgical treatment

BACKGROUND

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is characterized by multifocality of the tumors, which often scatter over the mucosa of the stomach and adjacent upper gastrointestinal tract, and is therefore theoretically not curable by surgical resection.

METHODS

We conducted a long-term follow-up study of 14 patients who received surgical treatment for gastric MALT lymphoma. Tissues from the surgical margins of the resected stomach were analyzed by polymerase chain reaction-based amplification of the complementarity-determining region 3 of the IgH gene for the presence of residual tumors. T (11;18)(q21;q21), a marker of Helicobacter pylori-independent MALT lymphoma, was analyzed by reverse transcription polymerase chain reaction. All living patients were restaged, and rebiopsied if suspicious lesions were identified.

RESULTS

At a median follow-up of 11.5 years, only 1 patient had evidence of tumor recurrence. Three patients with molecularly proven residual tumors in the surgical margin remained disease-free at 9.6 to 11.6 years. Five patients with t(11;18)(q21;q21) in the tumor cells were disease-free at 9.2 to 12.6 years.

CONCLUSION

Our results indicate that surgical resection is a highly curative treatment for gastric MALT lymphoma, even for patients with residual tumor cells in the surgical margins, and for patients with H. pylori-independent tumors. A revisit of surgical treatment for gastric MALT lymphoma is mandatory.

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.

Differential response toH. pylori eradication therapy of co-existing diffuse large B-cell lymphoma and MALT lymphoma of stomach—significance of tumour cell clonality and BCL10 expression

We recently reported that low-grade mucosa-associated lymphoid tissue lymphoma (MALToma) and diffuse large B-cell lymphoma (DLBCL) with MALToma (DLBCL[MALT]) of stomach are equally responsive to H. pylori eradication therapy (HPET) and that H. pylori-independent status is closely associated with nuclear translocation of BCL10. However, co-existing MALToma and DLBCL components of gastric DLBCL(MALT) may respond differentially to HPET and the underlying mechanism remains unclear. Tumour tissue samples from 18 patients with microdissectable co-existing MALToma and DLBCL cells were studied. The clonality of lymphoma cells was examined by polymerase chain reaction-based amplification of the CDR3 region of the IgH gene and confirmed by DNA sequence analysis. BCL10 expression was determined by immunohistochemistry. Differential response of co-existing MALToma and DLBCL to HPET was defined as complete eradication of one component while the other component remained. Five (27.8%) of the 18 patients showed different IgH gene rearrangements in the two components and three (60%) of these five patients had differential response of MALToma and DLBCL to HPET. By contrast, 13 patients showed identical IgH gene rearrangements and only one (8%) of them had differential response of the two components to HPET (p = 0.044). Further, all four patients with differential response of MALToma and DLBCL to HPET showed nuclear expression of BCL10 in the H. pylori-independent component and cytoplasmic expression of BCL10 in the H. pylori-dependent component while the expression patterns of BCL10 were identical in both of these components in the 14 patients who had similar tumour response to HPET. We conclude that different clonality is a common reason for the differential response of co-existing MALToma and DLBCL of gastric DLBCL(MALT) to HPET and that immunohistochemical examination of BCL10 expression may help to identify the co-existence of these components.

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.

Primary extranodal lymphomas of gastrointestinal localizations: a single institution 5-yr experience

This study is aimed at comparison of patients with extranodal lymphomas based on pathohistological findings differences (MALT vs non-MALT) as well as regarding gastric and non-gastric localization, and determining the significance of clinical-laboratory parameters with respect to therapeutic response and length of survival. A total of 56 patients with extranodal non-Hodgkin's lymphomas of the gastrointestinal tract were evaluated over a 5-yr period. Regarding the localization of the disease, the stomach was most frequently affected, 39 patients (70%); followed by small and large intestines, 17 patients. As for the pathohistological findings, MALT lymphoma accounted for 70%, DLBCL 25%, while other subtypes accounted for 5%. Patients' distribution was analyzed according to CS based on both Ann Arbor and Lugano systems; however, the difference obtained between the groups was not statistically significant in both staging types of patients. Statistically significant difference in patients' distribution was not found with respect to IPI index, bone marrow infiltration, anemia, hypoalbuminemia, or histological subtype and localization. Difference in survival between patients according to the pathohistological type was not statistically significant also according to the type of the affected gastrointestinal tract organ. Statistical significance of difference according to survival probability was obtained based on age (survival is longer in patients over 55 yr of age); according to CS and according to Ann Arbor and Lugano classifications (the patients with lower CS live significantly longer); according to IPI index (the survival is significantly longer in patients with lower probability: IPI-0,1, and 2), as well as patients free of bone marrow infiltration whose survival is also significantly longer.

Mucosa-associated lymphoid tissue (MALT) lymphoma

OBJECTIVES

To review the pathogenesis of MALT lymphoma, and the associations with antigenic stimulation, presentation, and unique treatment.

DATA SOURCES

Research and review articles and textbooks.

CONCLUSION

MALT lymphoma is a heterogeneous but unique pathologic form of extranodal B-cell non-Hodgkin's lymphoma. The gastrointestinal tract is the most common site of disease, but involvement of multiple other organ systems has been reported. In the case of gastric MALT lymphomas, H. pylori has been highly implicated as the stimulating agent. Treatment strategies for early disease involve eradication of H. pylori when it is involved and/or radiotherapy, which alone may result in cure of this lymphoma. Chemotherapy is used in more advanced or resistant disease.

IMPLICATIONS FOR NURSING PRACTICE

Nurses play a significant role in the education of patients about this unique malignancy and follow-up regarding compliance with therapy. Attention to social needs of the patients is critical.

Targeting NF-κB in hematologic malignancies

The transcription factor nuclear factor kappa B (NF-kappaB) can intervene in oncogenesis by virtue of its capacity to regulate the expression of a plethora of genes that modulate apoptosis, and cell survival as well as proliferation, inflammation, tumor metastasis and angiogenesis. Different reports demonstrate the intrinsic activation of NF-kappaB in lymphoid and myeloid malignancies, including preneoplastic conditions such as myelodysplastic syndromes, underscoring its implication in malignant transformation. Targeting intrinsic NF-kappaB activation, as well as its upstream and downstream regulators, may hence constitute an additional approach to the oncologist's armamentarium. Several small inhibitors of the NF-kappaB-activatory kinase IkappaB kinase, of the proteasome, or of the DNA binding of NF-kappaB subunits are under intensive investigation. Currently used cytotoxic agents can induce NF-kappaB activation as an unwarranted side effect, which confers apoptosis suppression and hence resistance to these drugs. Thus, NF-kappaB inhibitory molecules may be clinically useful, either as single therapeutic agents or in combination with classical chemotherapeutic agents, for the treatment of hematological malignancies.

Expression of CD86 and increased infiltration of NK cells are associated with Helicobacter pylori-dependent state of early stage high-grade gastric MALT lymphoma

AIM: A high percentage of early-stage high-grade gastric mucosa-associated lymphoid tissue (MALT) lymphomas remainHelicobacter pylori (H pylori)-dependent. However, unlike their low-grade counterparts, high-grade gastric MALT lymphomas may progress rapidly if unresponsive to H pylori eradication. It is mandatory to identify markers that may predict the H pylori-dependent status of these tumors. Proliferation of MALT lymphoma cells depends on cognate help and cell-to-cell contact of H pylori-specific intratumoral T-cells. To examine whether the expression of co-stimulatory marker CD86 (B7.2) and the infiltration of CD56 (+) natural killer (NK) cells can be useful markers to predict H pylori-dependent status of high-grade gastric MALT lymphoma.

METHODS: Lymphoma biopsies from 26 patients who had participated in a prospective study of H pylori-eradication for stage IE high-grade gastric MALT lymphomas were evaluated. Tumors that resolved to Wotherspoon grade II or less after H pylorieradication were classified as H pylori-dependent; others were classified as H pylori-independent. The infiltration of NK cells and the expression of CD86 in pre-treatment paraffin-embedded lymphoma tissues were determined by immunohistochemistry.

RESULTS: There were 16 H pylori-dependent and 10 H pylori-independent cases. CD86 expression was detected in 11 (68.8%) of 16 H pylori-dependent cases but in none of 10 H pylori-independent cases (P = 0.001). H pylori-dependent high-grade gastric MALT lymphomas contained significantly higher numbers of CD56 (+) NK cells than H pylori-independent cases (2.8±1.4% vs 1.10.8%; P = 0.003). CD86 positive MALT lymphomas also showed significantly increased infiltration of CD56 (+) NK cells compared to CD86-negative cases (2.9±1.1% vs 1.4±1.3%; P = 0.005).

CONCLUSION: These results suggest that the expression of co-stimulatory marker CD86 and the increased infiltration of NK cells are associated with H pylori-dependent state of early-stage high-grade gastric MALT lymphomas.

A case of multiple mucosa-associated lymphoid tissue (MALT) lymphoma of the colon identified as simple mucosal discoloration

Most colonic multiple mucosa-associated lymphoid tissue (MALT) lymphomas are confirmed with a histologic and immunohistochemical staining of the mucosal biopsy specimen obtained during colonoscopic examinations. Endoscopically, colonic MALT lymphomas frequently appear as protruding and/or ulcerative lesions, and there are not so many reports of colonic MALT lymphoma as compared to the frequent reports of MALT lymphoma of stomach. We report a unique case of colonic MALT lymphoma presenting as a simple reddish discoloration of mucosa; this presentation has never been describe before. Our patient was a 47-yr-old male who suffered from tenesmus and mucoid stool. A colonoscopy was accomplished, followed by a histologic examination and we diagnosed a colonic MALT lymphoma. Staging of the disease was done because this was necessary for choosing the modality of treatments. The patient was then treated with polychemotherapy in conjunction with radiation therapy.

Nuclear expression of BCL10 or nuclear factor kappa B predicts Helicobacter pylori-independent status of early-stage, high-grade gastric mucosa-associated lymphoid tissue lymphomas

PURPOSE

A high percentage of early-stage, high-grade gastric mucosa-associated lymphoid tissue (MALT) lymphomas remain Helicobacter pylori dependent. t(11;18)(q21;q21), a genetic aberration highly predictive of H. pylori-independent status in low-grade gastric MALT lymphoma, is rarely detected in its high-grade counterpart. This study examined whether nuclear expression of BCL10 or nuclear factor kappa B (NF-kappaB) is useful in predicting H. pylori-independent status in patients with stage IE high-grade gastric MALT lymphomas.

PATIENTS AND METHODS

Twenty-two patients who had participated in a prospective study of H. pylori eradication for stage IE high-grade gastric MALT lymphomas were studied. The expression of BCL10 and NF-kappaB in pretreatment paraffin-embedded lymphoma tissues was evaluated by immunohistochemistry and confocal immunofluorescence microscopy. The presence of t(11;18)(q21;q21) was identified by a multiplex reverse transcriptase polymerase chain reaction of the API2-MALT1 chimeric transcript.

RESULTS

Aberrant nuclear expression of BCL10 was detected in seven (87.5%) of eight H. pylori-independent and in none of 14 H. pylori-dependent high-grade gastric MALT lymphomas (P <.001). All seven patients with nuclear BCL10 expression had nuclear expression of NF-kappaB, compared with only two of 15 patients without nuclear BCL10 expression (P =.002). As a single variable, the frequency of nuclear expression of NF-kappaB was also significantly higher in H. pylori-independent tumors than in H. pylori-dependent tumors (seven of eight [87.5%] v two of 15 [12.3%]; P =.002). The API2-MALT1 fusion transcript was detected in only one (12.5%) of eight H. pylori-independent lymphomas.

CONCLUSION

Nuclear expression of BCL10 or NF-kappaB is highly predictive of H. pylori-independent status in high-grade gastric MALT lymphoma, and coexpression of these two markers in the nuclei is frequent.

Bronchial-associated lymphoid tissue lymphoma: a clinical study of a rare disease

Bronchial-associated lymphoid tissue (BALT) lymphoma is a distinct subgroup of low-grade B-cell extranodal non-Hodgkin's lymphoma, classified as marginal-zone lymphoma. This study was performed in order to assess the natural history of this rare entity. We evaluated retrospectively the clinical data of 22 patients with biopsy-proven BALT lymphoma at two tertiary-care institutions from 1996 to 2002. Immunophenotyping was done to confirm the abnormal populations of B-lymphoid cells in all cases, and clonality was determined by flow cytometry or molecular studies. There were 11 men and 11 women in the sample, median age 61 years (range 21-80 years); nine were asymptomatic at diagnosis. All 13 symptomatic patients had non-specific pulmonary complaints. On computed tomographic examination of the chest, 11 patients had bilateral disease, 12 had lung nodules, and 10 had a mass or air-space consolidation. In all but one case the disease was localised to the lung at diagnosis and none had peripheral blood or bone marrow involvement. Out of 22 patients, 20 received treatment in various combinations, 12 had chemotherapy and/or rituximab, six had surgery, and two received radiation therapy as primary treatment. A complete response (CR) was achieved in nine patients and a partial response was obtained in 10 patients. Seven of 10 patients who had unilateral disease achieved a CR. The estimated progression-free survival was 53 months. All patients were alive during the median follow-up period of 36 months (range 12-76 months). It appears that BALT lymphoma tends to be localised to lung at the time of diagnosis, responds well to local or systemic therapy, and has a favourable prognosis.

t(11;18)-Bearing Pulmonary Mucosa-Associated Lymphoid Tissue Lymphoma Responding to Cladribine

Mucosa-associated lymphoid tissue (MALT) lymphoma is a low-grade B-cell lymphoma and is usually slow to disseminate. The t(11;18)(q21;q21) translocation has been identified in a subset of MALT lymphoma cases, and AP12 and MLT1/MALT1 genes have been implicated in this translocation. However, the clinicopathologic features of t(11;18)-bearing MALT lymphoma have not been fully elucidated, and the optimal therapy for patients with disseminating disease is unknown. We report an outstanding case of MALT lymphoma that showed massive pulmonary infiltration and leukemic transformation during a prolonged course of more than 16 years. Reverse transcriptase-polymerase chain reaction and dual-color fluorescence in situ hybridization analyses confirmed the existence of the AP12/MLT1 fusion gene in the lymphoma cells. Peripheral blood lymphoma cells disappeared after glucocorticoid therapy. Although the pulmonary lymphoma was slowly progressive and caused severe hypoxemia despite the continuation of glucocorticoid therapy, treatment with cladribine induced a marked reduction of pulmonary lymphomatous lesions and an improvement of the hypoxemia. These findings show the unique clinical features of this particular indolent B-cell lymphoma with t(11;18) translocation and suggest the potential therapeutic usefulness of glucocorticoid and cladribine.

Activation of NF-kappaB and inhibition of p53-mediated apoptosis by API2/mucosa-associated lymphoid tissue 1 fusions promote oncogenesis

Mucosa-associated lymphoid tissue (MALT) lymphoma is the most common extranodal lymphoid cell neoplasia; it frequently follows chronic bacteria-induced inflammation in various tissues. MALT lymphomas are characterized genetically by the t(11;18)(q21;q21) translocation, which yields chimeric transcripts encoding structurally distinct API2/MALT1 fusion proteins. In this study, we provide functional evidence for the contribution of API2/MALT1 fusion proteins to transformation of cells in culture by activating the NF-kappaB pathway through a RelB/p50 dimer. Using microchip gene expression analysis, we demonstrate that different forms of the API2/MALT1 proteins activate both unique and overlapping gene programs in cells. In addition to this genome reprogramming, expression of distinct API2/MALT1 fusion products inhibits DNA damage-induced, p53-mediated apoptosis in an NF-kappaB-dependent manner. Collectively, these data reveal previously unknown functional diversity among API2/MALT1 fusion products and their function in NF-kappaB signaling as it connects to the apoptotic program, a pathway with strong relevance to cancer. Furthermore, they provide evidence underlying the emerging role of the NF-kappaB signaling pathway in the inhibition of apoptosis.

Sustained Remissions with Long-term Weekly Chlorambucil Maintenance Therapy in Patients with Mucosa-Associated Lymphoid Tissue Lymphoma

Five patients with mucosa-associated lymphoid tissue (MALT) lymphoma (Helicobacter pylori negative) were initially treated with daily chlorambucil (Chl, 0.06-0.08 mg/kg per day) and achieved complete remission (n = 4) or partial remission (n = 1). They were then given long-term weekly Chl as maintenance therapy with good results. One patient came off treatment and has remained in continued remission for 44 months. This simple, low-cost, and convenient approach deserves further evaluation in patients with MALT lymphoma and other indolent and incurable lymphoproliferative disorders.

Indolent lymphoma: the pathologist's viewpoint

Indolent lymphomas have recently been the object of numerous studies, which have focused on new aspects relevant both for the better comprehension of their histogenesis and the identification of new therapeutic strategies. As marginal-zone lymphoma (MZL) represents the category of indolent lymphomas that has obtained more benefit from such an approach, the authors focused on the most recent achievements and not yet solved controversies in this area. In spite of their postulated common derivation, the three categories of MZL of the WHO Classification appear dissimilar. In fact, they show significant molecular differences among them as well as a certain heterogeneity within each group. By no means, there is a cogent need of more refined tools to revise these neoplasms and to produce a more rational grouping. The recent identification of the IRTA gene family corresponding to IG-like receptors differentially expressed in B-cells might contribute to their better understanding.

Monoclonality in Helicobacter pylori-positive gastric biopsies: an early detection of mucosa-associated lymphoid tissue lymphoma

Mucosa-associated lymphoid tissue (MALT) is not present in healthy gastric mucosa, but it can develop in sites of long-persisting inflammation and is connected with the development of MALT lymphoma. A monoclonal lymphocyte population is one of the characteristics of such lymphomas. In this study we analyzed gastric biopsies (formalin fixed and paraffin embedded or frozen) in 93 patients with dyspepsia accompanied by Helicobacter pylori infection. We applied PCR and single-cell immunocytochemistry to detect the clonality of the gastric B-cell population. Immunocytochemistry performed on 33 frozen biopsies showed two samples with monoclonal pattern. PCR analysis of immunoglobulin heavy-chain (IgH) gene rearrangements revealed two monoclonal populations out of 161 biopsies from 60 patients. We conclude that PCR analysis was the most sensitive method, which gave us insight into the nature of the earliest stage of MALT lymphoma in gastric biopsies.

Outcome in relation to treatment modalities in 48 patients with localized gastric MALT lymphoma: a retrospective study of patients treated during 1976-2001

The aim of this study was to retrospectively analyze survival and tumor response data in patients with localized gastric MALT lymphoma treated by different treatment modalities other than anti-Helicobacter pylori treatment (diagnosis made before 1993, or after failure of antibiotics + anti-acid), including surgery, chemotherapy or combined treatment. Here we studied a series of 48 patients with stage IE or IIE disease treated during the past 11 years. These patients received different treatments: chemotherapy was proposed to 19 (40%) patients; gastric surgery to 21 (43%) patients, consisting of partial gastrectomy of 7 patients and total gastrectomy in 14 patients; combined treatment to 8 (17%) patients, consisting of surgery + chemotherapy in 7 patients and surgery + chemotherapy + radiotherapy in 1 patient. At diagnosis, 85% of the patients had good PS and no B symptoms. Complete response after treatment was reached in 45 (94%) patients (chemotherapy: 84% of the patients; surgery alone: 95%; combined treatment: 100%). Progression was observed in 16 (33%) patients. No statistical difference in the survival was found among the different therapeutic modalities: 5-year overall survival year FFP survival was 81% for chemotherapy, 86% for surgery alone and 95% for combined treatment. Prognostic factors for survival were age, performance status and hemoglobin level at diagnosis. Considering the natural bias of a retrospective analysis, surgery or chemotherapy was associated with a similar outcome in patients with MALT lymphoma after antibiotics failure.

Low-grade B-cell bronchial associated lymphoid tissue (BALT) lymphoma

Low-grade B-cell bronchial associated lymphoid tissue (BALT) lymphoma is a distinct subgroup of non-Hodgkin's lymphoma. Chronic antigen stimulation, triggered by autoimmune process or persistent infection may precede the development of BALT lymphoma. The lymphoma cells originate from the marginal zone and by invading the bronchial epithelial tissue, give rise to the lymphoepithelial lesion. BALT lymphoma shares the morphologic, immunophenotypic, and cytogenetic characteristics of other mucosa associated lymphoid tissue lymphomas. A majority of the patients are asymptomatic and pulmonary lesions are incidentally discovered on a routine chest radiograph. However, the clinical and radiographic features of BALT lymphoma are nonspecific. The disease is often localized at the time of diagnosis and responds favorably to local treatment, but the optimal management is not clearly defined. Overall, BALT lymphoma has a favorable prognosis and is associated with long-term survival.

Hepatitis C and B-cell lymphoma: the hemato-hepatologist linkage

Hepatitis C virus (HCV)-lymphotropism may be responsible for the development of mixed cryoglobulinemia (MC) and other lymphoproliferative disorders associated with HCV infection. An association between HCV infection and B-cell lymphoma has been largely demonstrated in several geographical areas with prevalence ranging between 7.4 and 37%. However, the intimate pathogenetic mechanism involved in HCV-associated lymphomas remains considerably unknown. HCV may exerts its oncogenic potential via an indirect mechanism or utilizes other pathways directly. It is reasonable to assume that several different pathogenetic mechanisms operate in the wide spectrum of HCV-related lymphomas which includes the 'idiopathic', non-cryoglobulinemic, intermediate to high-grade lymphoma, and the more common indolent, low-grade lymphoma, preceded by long standing symptomatic MC type II. In most cases, HCV has no significant impact on response to chemotherapy or survival of lymphoma patients. Treatment with chemotherapy is relatively safe, and interruption of treatment regimens is usually not required. Whether to treat low-grade HCV-related lymphomas with anti-viral therapy is still debatable, but encouraging data emerge from recent studies.

NF-kappaB in cancer: from innocent bystander to major culprit

Nuclear factor of kappaB (NF-kappaB) is a sequence-specific transcription factor that is known to be involved in the inflammatory and innate immune responses. Although the importance of NF-KB in immunity is undisputed, recent evidence indicates that NF-kappaB and the signalling pathways that are involved in its activation are also important for tumour development. NF-kappaB should therefore receive as much attention from cancer researchers as it has already from immunologists.

Indolent behaviour of low-grade B cell lymphoma of mucosa-associated lymphoid tissue arising in the kidney

We report a case of low-grade MALT lymphoma (mucosa-associated lymphoid tissue) arising in the kidney. It had very indolent behaviour with multiple extranodal relapses (parotid gland, orbit, skin, breast, prostate) over a period of 13 years; presently, the patient is asymptomatic.

Canine T-cell lymphomas: a morphological, immunological, and clinical study of 46 new cases

The aim of this study is to report 46 new cases of canine T-cell lymphomas among a series of 140 lymphomas studied by immunophenotyping (incidence 32.8%). According to the updated Kiel classification adapted to the canine species, 13 were classified as low-grade and 33 as high-grade lymphomas. Among the low-grade lymphomas, five were small clear-cell lymphomas, three were pleomorphic small-cell lymphomas, and five mycosis fungoides. Among the high-grade cases, there were 11 pleomorphic mixed-, small-, and large-cell lymphomas, 6 pleomorphic large-cell lymphomas, 11 lymphoblastic lymphomas, and 5 unclassifiable high-grade plasmacytoid lymphomas. The cytohistologic features were highly suggestive of a T-cell phenotype on the basis of cell morphology (irregular nuclei and clear cytoplasms) (30/46 cases), a T-cell zone pattern, and the presence of hyperplastic postcapillary venules (22/46 cases). All 46 cases were CD3+ CD79a-, and among 34 cases investigated for CD4 and CD8 expression, 13 were CD4+CD8-, 13 were CD8+CD4-, and 8 were CD4CD8 double positive or double negative. The pleomorphic mixed lymphomas were mainly CD4+CD8- (6/7) and the lymphoblastic lymphomas were double positive or double negative (6/8). The main clinical, hematologic, and biochemical features were generalized (28/46) or regional lymphadenopathy (16/46), hepatosplenomegaly (15/46), extranodal involvement (11/46), mediastinal mass (9/46), and leukemia (8/46), which were mainly present in cases of lymphoblastic lymphomas and hypercalcemia (16/46).

Prospective study of Helicobacter pylori eradication therapy in stage I(E) high-grade mucosa-associated lymphoid tissue lymphoma of the stomach

PURPOSE

High-grade mucosa-associated lymphoid tissue (MALT) lymphomas of the stomach are generally believed to be Helicobacter pylori-independent, autonomously growing tumors. However, anecdotal cases of regression of high-grade lymphomas after the cure of H pylori infection had been described. The present prospective study was conducted to evaluate the effect of anti-H pylori therapy in stage I(E) high-grade gastric MALT lymphomas.

PATIENTS AND METHODS

Sixteen patients with H pylori infection and stage I(E) gastric high-grade MALT lymphoma consented to a brief antibiotic therapy as first-line treatment from June 1995 through April 2000. Then, patients underwent intensive endoscopic follow-up examinations (+/- endoscopic ultrasonography) with biopsy to evaluate tumor response. Patients with significant improvement of gross lesions that accompanied regression of large cells were followed up without additional treatment. Patients without significant improvement were immediately referred to systemic chemotherapy.

RESULTS

Eradication of H pylori was achieved in 15 patients and was accompanied by rapid gross tumor regression and disappearance of large cells in 10. All 10 of these patients with early response had subsequent complete histologic remission of lymphoma. The complete remission rate was 62.5% (95% confidence interval, 35.8% to 89.1%). The response rate was not affected by the tumor grading (proportion of large blast cells within the tumor) but was adversely affected by the depth of tumor invasion. At a median follow-up of 43.5 months (range, 21.1 to 67.4 months), all 10 of these patients remained lymphoma-free. The median duration of complete response was 31.2 months (range, 14.4 to 49.1 months).

CONCLUSION

These results suggest that high-grade transformation is not necessarily associated with the loss of H pylori dependence in early-stage MALT lymphomas of the stomach.

Clonal evolution of gastric lymphoma of mucosa-associated lymphoid tissue type

Development of multiple lesions is frequent in gastric lymphoma of mucosa-associated lymphoid tissue (MALT) type. Presence of clonal components in multiple lesions was examined on the resected samples from 18 cases by using PCR-based method for immunoglobulin heavy-chain gene rearrangement. There were two or more lesions in 10 cases, and 2 to 12 samples were obtained from each lesion. The remaining eight cases had a single large lesion, from which two to six samples were collected from separate areas from each other. A total of 86 samples were analyzed. Histologic findings in each sample were categorized as follows: proliferation of exclusively centrocyte-like cells (CCL), large cells, and combined CCL and large cells. Monoclonal or biclonal pattern (single or two bands) was observed in 42 samples, oligoclonal pattern (three or more bands) in 30, polyclonal (smear) in 11, and no products in 3. Large-cell-type lesions showed fewer bands than those with other histologic types, and 75% of cases with large-cell type had mono- or biclonal proliferation. Common clones were found among lesions in about 60% of cases. Especially in 4 cases including 2 cases with large-cell type, every lesion in the same case contained the common clones. These findings suggested that gastric MALT lymphoma started as multi- or oligoclonal proliferation of cells, in which separate lesions composed of different clones from each other. As disease advances, dominant clones appear in some lesion and disseminate to other lesions via homing properties of the proliferating B lymphocytes.

Seroepidemiological study of Helicobacter pylori infection in asymptomatic people in South Korea

BACKGROUND

Helicobacter pylori infection occurs throughout the world and causes gastroduodenal diseases in all age groups. The prevalence of H. pylori infection varies between countries and races. The aim of this study was to evaluate the seroprevalence of H. pylori infection in asymptomatic healthy people in South Korea.

METHODS

From March 1998 to October 1998, 5732 asymptomatic subjects who responded to the self-assessment questionnaires from 54 hospitals in South Korea were enrolled in this study. The serum levels of antibodies for H. pylori immunoglobulinG were measured by using an ELISA test.

RESULTS

The overall seroprevalence of H. pylori infection was 46.6% and there was no statistical difference between males (47.2%) and females (45.9%). In adults, a significant difference was observed between genders. According to the geographic areas, the high prevalent provinces were Kangwon (53.4%), Cheju (52.9%) and Cholla province (50.6%); Seoul (41.9%) was the lowest prevalent area. The seroprevalence increased with age and was highest when patients were aged in their 40s (78.5%). The characteristic feature of our study was that the infection rate was steeply increased in three age groups (10-12 year olds, 16-19 year olds and those aged in their 20s). In Seoul, there was no difference in the prevalence rate among the districts studied.

CONCLUSIONS

This nation-wide seroprevalence of H. pylori infection in South Korea was 46.6%, which showed the transition from a developing country to a developed country. More studies on the epidemiological factors and the route of transmission of H. pylori infection should be warranted.

Changes in pattern of immunoglobulin heavy chain gene rearrangement and MIB-1 staining before and after eradication of Helicobacter pylori in gastric mucosa-associated lymphoid tissue (MALT) lymphoma

Gastric low-grade mucosa-associated lymphoid tissue (MALT) lymphomas are strongly associated with infection by Helicobacter pylori (H. pylori). Antibiotic treatment for H. pylori induces a sustained remission in a significant number of patients. We report here the outcome in 13 patients with gastric low-grade MALT lymphomas or suspected gastric lesions, treated for eradication of H. pylori. Patients were followed closely with sequential histological studies, polymerase chain reaction (PCR) amplification of the immunoglobulin heavy chain (IgH) gene and immunohistochemistry for MIB-1. Antibiotic therapy resulted in eradication of H. pylori in all but one case, as assessed histologically. In 12 cases with successful eradication, complete regression was observed histologically in 9 cases (75%) and no regression in 3 (25%). In 7 of 9 (78%) patients who had a complete remission, clonal bands of IgH gene detected on PCR before therapy disappeared after therapy. All 9 patients with complete regression showed a reduced number of MIB-1 positive cells, while 4 cases with no change or disease progression showed no change or increased number of MIB-1 positive cells. There was a strong relationship between density of MIB-1-positive cells and histological score. These results indicate that combination analysis of PCR of IgH and MIB-1 seems to represent a very good current approach for the diagnosis of gastric low-grade MALT lymphoma and to assess the effects of chemotherapy, especially in problematic cases.

Stage I and II MALT lymphoma: results of treatment with radiotherapy

PURPOSE

Mucosa-associated lymphoid tissue (MALT) lymphoma is a distinct disease with specific clinical and pathologic features that may affect diverse organs. We analyzed our recent experience with Stage I/II MALT lymphoma presenting in the stomach and other organs to assess the outcome following involved field radiation therapy (RT).

PATIENTS AND METHODS

Seventy patients with Stage IE (62) and IIE (8) disease were treated between 1989 and 1998. Patients with transformed MALT were excluded. The median age was 62 years (range, 24--83 years), M:F ratio 1:2.2. Presenting sites included stomach, 15; orbital adnexa, 19; salivary glands, 15; thyroid, 8; lung, 5; upper airways, 3 (nasopharynx, 2; larynx, 1); urinary bladder, 3; breast, 1; and rectum, 1. Staging included site-specific imaging, CT abdomen in 66 patients (94%) and bone marrow biopsy in 54 (77%). Sixty-two patients received radiation therapy: 52 received RT alone, 7 received chemotherapy and RT, and 3 received antibiotics followed by RT. Median RT dose was 30 Gy (range, 17.5--35 Gy). Most frequently used RT prescriptions were 25 Gy (26 patients-18 orbit, 6 stomach, and 2 salivary glands), 30 Gy (23 patients), and 35 Gy (8 patients). Five patients had complete surgical excision of lymphoma and no other treatment (stomach 1, salivary 2, lung 2), whereas 2 patients with gastric lymphoma received antibiotics only. One patient refused treatment and was excluded from the analysis of treatment outcome, leaving 69 patients with a median follow-up of 4.2 years (range, 0.3-11.4 years).

RESULTS

A complete response was achieved in 66/69 patients, and 3 patients had partial response (2 lung, 1 orbit). The 5-year disease-free survival (DFS) was 76%, and the overall survival was 96%. No relapses were observed in patients with stomach and thyroid lymphoma. The 5-year DFS for these patients was 93%, in contrast to 69% for patients presenting in other sites (p = 0.006). Among the 5 patients treated with surgery only, 2 relapsed locally (lung, and minor salivary gland). Among 62 patients who received RT, 8 relapsed (2 salivary, 3 orbit, 1 nasopharynx, 1 larynx, 1 breast). Three patients relapsed in the nonirradiated contralateral paired organ, 4 in distant sites, and 1 in both local and distant sites. The overall local control rate with radiation was 97% (60/62 patients).

CONCLUSION

Localized MALT lymphomas have excellent prognosis following moderate-dose RT. Gastric and thyroid MALT lymphomas have better early outcome, as compared to the other sites where distant failure is more common. Relapses were observed in nonirradiated paired organs or distant sites. Further follow-up is required to assess the impact of failure on survival.

A novel recurrent translocation t(11;14)(p11;q32) in splenic marginal zone B cell lymphoma

A novel recurrent translocation t(11;14)(p11;q32) was found in three patients with splenic marginal zone B cell lymphoma (MZBCL). Fluorescence in situ hybridization (FISH) studies with IgH probes revealed in all cases involvement of the IgH locus, with breakpoint downstream of the IGVH sequences. Partner genes at 11p11 were not identified. The translocation defined the stem line in two patients, who carried additional cytogenetic aberrations, including a 17p deletion, present in both cases. In one patient a 7q- chromosome was the primary cytogenetic defect, the t(11;14) having been found in four out of 11 abnormal metaphase cells at the time of transformation into high-grade MZBCL. Hematological features in all cases included splenomegaly with peripheral blood (PB) involvement by a monoclonal B cell population consisting of lymphocytes with villous projections and several blast-like cells. The immunophenotype was CD19+; CD22bright+; CD23-, CD10-, CD5-, surface Igbright+. A bone biopsy in one patient revealed an interstitial infiltration with an intrasinusoidal pattern of growth. Histological studies on spleen specimens in two patients showed an expanded marginal zone, with small lymphocytes and several blast-like cells. One patient had a therapy-demanding disease, with partial, short-term responses to cytotoxic treatment; one patient transformed into a high-grade MZBCL involving the gut, the PB and the bone marrow 2 years after diagnosis; one patient was unresponsive to cytotoxic treatment and underwent splenectomy. The t(11;14)(p11;q32) may define a subset of splenic MZBCL with a high-grade component and a relatively aggressive clinical behavior.

The effect of antiviral therapy on t(14;18) translocation and immunoglobulin gene rearrangement in patients with chronic hepatitis C virus infection

The mechanism of lymphomagenesis of hepatitis C virus (HCV)–related B-cell lymphoma is unknown. Recently, it has been suggested that HCV may induce B-cell clonal proliferation and t(14;18) translocation in patients chronically infected with the virus. Thus, this study investigated the effect of antiviral treatment on immunoglobulin heavy-chain gene (IgH) rearrangement and t(14;18) translocation in HCV infected patients. Twenty-nine patients with chronic HCV infection were studied in whom IgH rearrangement and/or t(14;18) translocation were previously detected. The IgH rearrangement (FR3/JH) and t(14;18) translocation (MBR bcl2-JH) were detected in peripheral blood mononuclear cells by polymerase chain reaction. Fifteen of 29 patients (8 with IgH rearrangement, 6 with t(14;18) translocation, and 1 with both) were treated with either interferon-α or by combination therapy with interferon and ribavirin for 6 to 12 months. IgH rearrangement became negative in 7 of 9 treated patients compared with only 1 of 8 of nontreated patients (P &lt; .02). The t(14;18) translocation became negative in 6 of 7 treated patients compared with 1 of 6 nontreated patients (P = .03). Disappearance of IgH rearrangement or t(14;18) translocation was strongly associated with virologic response to treatment. Two t(14;18)+patients developed B-cell lymphoma during follow-up. Antiviral treatment appears to be effective in eliminating the clonal proliferation of B cells in patients with chronic HCV infection and may prevent the subsequent development of lymphoma. The mechanism can be related to a direct effect of interferon-α on the proliferating clone or to an indirect effect by eradicating the antigenic stimulus.

Comparison of MALT and non-MALT primary large cell lymphoma of the stomach: does histologic evidence of MALT affect chemotherapy response?

BACKGROUND

Although the clinicopathologic features of low grade gastric MALToma (lymphoma of mucosa-associated lymphoid tissue) recently have been well delineated, the significance of identifying histologic evidence of MALT origin in a primary high grade gastric lymphoma is less clear. The authors sought to address this issue and, in particular, to clarify if MALT and non-MALT primary large cell gastric lymphoma might have a different response to systemic chemotherapy.

METHODS

The authors reviewed the pathologic specimens of all patients who had a diagnosis of primary large cell lymphoma of the stomach and who had been treated primarily by systemic chemotherapy in our institutions January 1, 1988-December 31, 1998. The patients were divided into two groups by experienced hematopathologists, based on the presence or absence of histologic features suggestive of MALToma, including typical lymphoepithelial lesions and infiltration of characteristic centrocyte-like cells. Disease staging was done according to the AJCC/UICC system with Musshoff modification. The median number of gastric biopsies for each patient was 7 (range, 1-21).

RESULTS

Seventeen patients with and 26 patients without histologic evidence of MALToma were identified. Clinical features were similar between the two groups except that a greater proportion of patients without evidence of MALToma had elevated levels of serum lactate dehydrogenase (50% vs. 12%, P = 0.01). The median duration of follow-up for the 43 patients was 46.5 months (range, 17-124 mos). All patients received standard systemic chemotherapy including anthracyclines or anthracenedione. The response rate was 88.2% for patients with evidence of MALToma and 57.7% for those without (P = 0.03). The 5-year overall survival rate was 80.5% for patients with evidence of MALToma and 48.9% for those without (P = 0.02). Multivariate analysis indicated that response to chemotherapy, disease stage (Stage I and II-1 vs. Stage II-2, III, and IV), and the presence of MALToma features were independent prognostic factors for overall survival.

CONCLUSION

The results of this relatively small study series suggested that the presence of histologic features of MALToma in patients with primary large cell gastric lymphoma might have been associated with a better response to systemic chemotherapy and a better prognosis. Further studies to consolidate this conclusion are necessary.

MALT Lymphomas

This review addresses the biology and the treatment of lymphomas arising from mucosa-associated lymphoid tissue (MALT). This entity, first described in 1983, represents about 8% of all non-Hodgkin's lymphomas and was recently re-classified as "extranodal marginal zone lymphomas of MALT-type." The term marginal zone lymphoma (MZL) encompasses the three closely related lymphoma subtypes of nodal, primary splenic and extranodal lymphomas of MALT type: the latter represent the vast majority of MZL. These lymphomas arise at different anatomic sites, are composed of mature B-cells lacking expression of CD5 and CD10, often present with overlapping morphologic features, but typically quite distinct clinical behaviors. Only very recently cytogenetic/molecular genetic observations have underlined the distinctiveness of these three lymphoid neoplasms, which in both the R.E.A.L. and WHO-classifications are included in the general term of MZL. MALT lymphomas arise in numerous extranodal sites, but gastric MALT lymphoma is the most common and best studied and is, therefore, the paradigm for the group as a whole. Dr. Isaacson describes the principal histological features of these lymphomas, including criteria to distinguish this entity from other small B-cell lymphomas. Several lines of evidence suggest that gastric lymphoma arises from MALT acquired as the result of aH. pyloriinfection. However, at least 1/3 of cases do not respond to eradication ofH. pylori. Very recent data suggest that both t(11;18) (q21;q21) and bcl10 nuclear expression are associated with failure to respond to this treatment. Dr. Gascoyne discusses the biologic function of proteins deregulated through the different translocations, which play a role in pathogenesis of MALT lymphomas, emphasizing particularly their influence in disrupting the apoptotic pathway. Dr. Zucca reviews findings suggesting that MALT lymphoma is an antigen driven neoplasm. He also presents specific guidelines for treatment of gastric lymphomas trying to shed some light on the amazingly inconsistent and confusing data in the literature. Taking advantage on the more than 300 non-gastric MALT lymphomas collected by the International Extranodal Lymphoma Study Group (ILESG), Dr. Cavalli compares gastric lymphomas with those arising in many other sites. Overall, the data presented in this session will underline the fact, that MALT lymphomas are characterized by some unique biological properties.

Clone-specific PCR reveals wide dissemination of gastric MALT lymphoma to the gastric mucosa

The development of low-grade gastric mucosa-associated lymphoid tissue (MALT) lymphoma is closely associated with Helicobacter pylori infection. Despite its indolent clinical course and prolonged localization to the site of origin, the lymphoma frequently presents with multifocal lesions. However, the true extent of tumour involvement in the gastric mucosa is unclear, since reactive appearing lymphocytic infiltrates are always present and could contain tumour cells that are not readily identifiable on cytological grounds. Gastrectomy specimens of four MALT lymphoma cases were studied by microdissection and clone-specific polymerase chain reaction (CS-PCR) and of a further case with t(1;14)(p22;q32) by immunohistochemistry for BCL10 protein, which acted as a tumour marker for tumour cells carrying the translocation. CS-PCR revealed that tumour cells were commonly present in histologically non-lymphomatous lymphocytic infiltrates microdissected from areas well separated from tumour lesions. Tumour cells were also frequently found in infiltrates microdissected from the resection margins. These findings were reinforced by direct identification of tumour cells, as recognized by strong BCL10 nuclear staining, in non-lymphomatous lymphocytic infiltrates in the case with t(1;14)(p22;q32). The results show that gastric MALT lymphoma disseminates widely within the gastric mucosa without necessarily forming diagnostic lesions.