Reassessment of gastric lymphoma in light of the concept of mucosa-associated lymphoid tissue lymphoma

Marginal-zone lymphoma

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

Radiographic findings of primary B-cell lymphoma of the stomach: low-grade versus high-grade malignancy in relation to the mucosa-associated lymphoid tissue concept

OBJECTIVE

We undertook this study to assess how well double-contrast radiography and CT allow radiologists to differentiate low-grade from high-grade mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach.

MATERIALS AND METHODS

We retrospectively reviewed the upper gastrointestinal radiographs and contrast-enhanced CT scans of 57 patients with pathologically proven primary gastric lymphoma (low-grade [n = 29] and high-grade [n = 28] MALT lymphoma).

RESULTS

On upper gastrointestinal radiography, ulceration (39%) was the most common finding in low-grade lymphoma, whereas polypoid appearance (38%) was the most common in high-grade lymphoma. In the 29 patients (33 lesions) with low-grade MALT lymphoma, upper gastrointestinal radiography revealed 13 ulcerative lesions (39%), 10 nodular lesions (30%), four infiltrative lesions (12%), two polypoid lesions (6%), and four combined lesions (12%). In the 28 patients (29 lesions) with high-grade lymphoma, upper gastrointestinal radiography revealed 11 polypoid lesions (38%), nine infiltrative lesions (31%), six ulcerative lesions (20%), one nodular lesion (3%), and two combined lesions (7%). On CT, thickening of the gastric wall in low-grade lymphoma (range, 0.3-2.5 cm; mean, 0.8 cm) was much less than that in high-grade lymphoma (range, 0.7-8.0 cm; mean, 2.5 cm). Abdominal lymphadenopathy was less frequent in low-grade lymphoma (14%) than in high-grade lymphoma (75%).

CONCLUSION

Most low-grade lymphomas show superficial spreading lesions, such as mucosal nodularity, shallow ulcer, and minimal fold thickening, on upper gastrointestinal radiography, whereas most high-grade lymphomas show mass-forming lesions or severe fold thickening.

Gastric mucosa-associated lymphoid tissue lymphoma: helical CT findings and pathologic correlation

OBJECTIVE

The purpose of this study was to describe helical CT findings of gastric mucosa-associated lymphoid tissue (MALT) lymphoma and to correlate them with pathologic findings.

MATERIALS AND METHODS

We retrospectively reviewed CT examinations of 58 patients with confirmed gastric MALT lymphomas. Using the histopathologic grade of the MALT lymphomas, we divided the patients into two groups: those with high-grade lymphoma (n = 21) and those with low-grade lymphoma (n = 37). Common CT findings for the two groups were reviewed and compared.

RESULTS

Forty (69%) of the 58 patients showed at least one abnormality of the stomach on CT. Abnormalities included diffuse or segmental gastric wall thickening (66%, 38/58), lymphadenopathy (40%, 23/58), ulcer (22%, 13/58), and gastric mass (3%, 2/58). Eighteen (31%) of 58 patients were found to have no abnormality. The high-grade group had a higher incidence of abnormalities seen on CT than the low-grade group (100% vs 51%, respectively). Gastric wall thickening in the high-grade group was more diffuse (48% vs 8%) and severe (71% vs 14%; severe or moderate) than that seen in the low-grade group. Lymphadenopathy was visualized in 67% of the high-grade group and in 24% of the low-grade group. Gastric ulcer was found in 57% of the high-grade group and in only 5% of the low-grade group. The gastric mass formation was seen in only two patients in the high-grade group.

CONCLUSION

The CT findings of gastric MALT lymphoma that the two groups had in common were gastric wall thickening and lymphadenopathy. Although our results pointed to no specific CT finding for differentiating high-grade from low-grade gastric MALT lymphomas, we found that the absence of abnormality on CT is highly predictive of low-grade MALT lymphoma.

Primary gastrointestinal B-cell lymphoma. A clincopathological and immunohistochemical study of 61 cases with an evaluation of prognostic parameters

We hereby present a retrospective clinicopathological and immunohistochemical study of surgically resected primary gastrointestinal (GI) lymphoma with an analysis of parameters of potential prognostic relevance. From a larger series of 144 cases of primary GI lymphomas, we chose 61 cases with sufficient clinical follow-up (mean 60, range 1-219 months), classified either as extranodal marginal zone B-cell lymphoma of MALT type (MALT lymphoma) or diffuse large B-cell lymphoma (DLBCL), after having excluded other subtypes. In addition to conventional clinical and morphological parameters, the expression levels of Ki-67 (MIB-1), bcl-2 and p53 were evaluated for prognostic significance. Twenty-one (34.4%) cases were classified as pure low grade marginal zone B-cell lymphoma of MALT type, 12 (19.7%) cases as low grade MALT lymphoma with a high grade component (mixed type), and 28 (45.9%) cases as primary extranodal DLBCL. Most of the lymphomas (53/61; 86.9%) were localized in the stomach, 3 (4.9%) in the small bowel, 3 (4.9%) multifocal in both stomach and small intestine and 2 (3.3%) in the large bowel. MIB-1 expression in more than 30% of tumor cells was detected in 42 (68.6%), bcl-2 expression in 20 (32.8%) and p53 accumulation in more than 10% of neoplastic cells in 16 (26.2%) lymphomas. Both high Ki-67 expression and p53 accumulation were more prevalent in the DLBCL. 30 (49%) patients showed lymph node involvement at surgery, 14 (23%) patients suffered tumor recurrence, and 24 (38.5%) died during the follow-up period. Tumor recurrence occurred primarily in patients who had presented lymph node involvement (9/14, 64.3%). The 5-year survival rate was 66.1% for all patients. Important prognostic factors for overall survival were tumor stage (p < .004) and p53 accumulation (p < .05) in univariate analysis, and tumor stage in multivariate analysis (p < .001). Although p53 accumulation did not reach statistical significance in our small study group, it may be both important in the transformation of low grade MALT lymphoma and an indicator for aggressive behavior in high grade tumors.

Benign lymphoepithelial lesion associated with squamous cell carcinoma of the skin: an immunohistochemical and molecular genetic study

BACKGROUND

Benign lymphoepithelial lesions (BLEL) are usually found in salivary glands in autoimmune disorders. Some LEL are recognized to already be, or may progress to become, lymphomas. Skin lesions similar to LEL have been described in lymphomas, and are caused by neoplastic lymphocytes which infiltrate adnexal structures. To date, BLEL have not widely been recognized in the skin.

METHODS

We describe skin lesions similar to BLELs, at the periphery of squamous cell carcinomas (SCC) in 8 healthy patients, in one of whom the lesion recurred. Immunocharacterization of both epithelial and lymphocytic components and molecular genetic investigation was performed. Polymerase chain reaction (PCR) analysis was done to detect IgH chain gene, and T-cell receptor beta and gamma gene rearrangements. Association with Epstein-Barr virus (EBV) was also tested by in situ hybridization (ISH) for EBV-encoded RNAs (EBERs).

RESULTS

Epithelial cells showed the immunophenotype of eccrine sweat gland ducts. Infiltrating lymphocytes expressed overwhelming B antigens and CD5. Neither clonal B and/or T proliferations nor EBERs signals were demonstrable.

CONCLUSIONS

We observed skin lesions similar to BLELs, showing modifications of sweat gland duct and CD5+, B lymphocytic expansion. In our cases there were no associated autoimmune disorders; the local immunoresponse to SCC might have caused BLEL.

Gastric mucosa-associated lymphoid tissue lymphoma: spectrum of findings at double-contrast gastrointestinal examination with pathologic correlation

Mucosa-associated lymphoid tissue (MALT) is found in the surface epithelium of the stomach. MALT lymphoma is extranodal lymphoma originating from MALT. In the stomach, a strong association with Helicobacter pylori infection has been demonstrated. Low-grade gastric MALT lymphoma has been reported to have variable features at upper gastrointestinal (UGI) examination. Twenty-two patients with low-grade MALT lymphoma had ulcers (n = 11), fold thickening (n = 7), mucosal nodularity (n = 7), masses (n = 6), or prominent areae gastricae (n = 4) at UGI examination. Six patients with high-grade MALT lymphoma had masses (n = 4), fold thickening (n = 3), ulcers (n = 1), or mucosal nodularity (n = 1) at UGI examination. These findings were similar to those in gastric carcinoma or gastritis. Differentiation of low-grade MALT lymphoma from gastritis or gastric carcinoma was more difficult than differentiation of high-grade MALT lymphoma. Lesions of MALT lymphoma associated with H pylori gastritis were diffuse or multiple in 65% of cases; however, lesions of MALT lymphoma without proved H pylori gastritis were focal or solitary in 80% of cases. Therefore, multiplicity of lesions in MALT lymphoma was closely associated with H pylori infection.

Multiple organ mucosa-associated lymphoid tissue lymphomas often involve the intestine

BACKGROUND

Low grade mucosa-associated lymphoid tissue (MALT) lymphomas usually are confined to single extranodal organs. Although some case reports have been published, clinicopathologic characteristics of multiorgan MALT lymphomas remain unclear.

METHODS

The authors evaluated 7 MALT lymphoma cases involving multiorgans in the past 7 years. In this period, they experienced 304 cases of MALT lymphomas. They analyzed the clinicopathologic features of these cases, including examination of clonal comparison among the lesions.

RESULTS

The patients, 4 females and 3 males, were aged 55-68 years old (average, 60.1 years). Four cases showed multiple organ involvement at the initial diagnosis or after a short period. In the other three cases, primary foci were the stomach, thyroid gland, and ocular adnexa; after a rather long period (3 years or more), distant metastases were found. Although intestinal primary lymphomas are rather rare, six of the seven cases showed large intestinal involvement. Lymph node involvement was proven in only three cases. The patients were rather resistant to the various therapeutic approaches. Although six patients are alive, five are with disease. DNA analyses revealed that in five of the cases evaluated, identical clones were detected among the different affected organs.

CONCLUSIONS

Multiorgan MALT lymphomas are rather rare. Most cases probably derived from a single clone, and lymphoma cells may selectively move among MALTs via a homing system with preferential involvement of the colon. Because multiorgan MALT lymphomas rarely achieve complete remission by treatment with combination chemotherapy or irradiation, MALT lymphomatous lesions should be checked carefully, especially in the large intestine.

Prognostic significance of the histopathologic recognition of low- and high-grade components in stage I-II B-cell gastric lymphomas

The prognostic value of histopathologic features was assessed in 83 patients with stage I-II gastric B-cell lymphomas (PGL). The following histotypes were considered: low-grade mucosa-associated lymphoid tissue (MALT)-type lymphoma (LGML; n = 35), diffuse large B-cell lymphoma with areas of MALT-type lymphoma (DLCLML; n = 20) and diffuse large B-cell lymphoma without areas of MALT-type lymphoma (DLCL; n = 28). Low-grade (LG) and high-grade (HG) components, lymphoepithelial lesions (LEL), size of cells giving rise to LEL, and amount and growth pattern of large cells (LC) were analyzed. Five-year cause-specific survival (CSS) for patients with LGML, DLCLML, and DLCL were 94%, 84%, and 64%, respectively (p = 0.05). LG component or LEL were associated with a significantly longer 5-year CSS, whereas the presence of an HG component, defined as clustered LC greater than 10% of neoplastic population, was significantly related to a shorter survival. Lymphomas with LC disposed in clusters were associated with a worse survival in comparison with cases with scattered LC. The presence of scattered LC 5%-10% appeared irrelevant in LGML. When analysis was limited to DLCLML/ DLCL patients, the presence of LG component or LEL was associated with a significantly longer 5-year CSS, whereas the existence of LEL formed by LC (HG LEL) did not modify survival. Multivariate analysis, adjusted by the main prognostic factors, confirmed the independent and significant association between histopathologic categorization and survival. Age, stage, lactate dehydrogenase (LDH) ratio, thrombocytopenia, and use of chemotherapy had independent prognostic value. In conclusion, histopathologic categorization is an independent prognosticator in PGL. The formation of compact clusters by LC, rather than their amount, is a true prognostic variable. The presence of scattered LC 5%-10% appears irrelevant in LGML. LG component and LEL are favorable predictors in HG lymphomas, helping to identify two subsets of DLCL with different prognosis.

Histologic and immunohistologic findings and prognosis of 40 cases of gastric large B-cell lymphoma

It has been considered that gastric large B cell lymphoma mainly consists of mucosa-associated lymphoid tissue lymphoma (MALToma) with large cell transformation. However, debate continues about the cell lineage. We analyzed 61 operated cases of gastric B cell lymphoma, mainly focusing on 40 cases of diffuse large cell lymphoma (DLCL). Immunohistologically, two cases were classified as CD10-positive follicular lymphoma, 19 cases were low-grade MALToma, 11 CD10-negative DLCL with a component of low-grade MALToma (high-grade MALToma), 12 CD10-positive DLCL, and 17 CD10-negative DLCL without MALToma (pure DLCL). Lymphoepithelial lesion (LEL) was found in all -cases of high-grade MALToma, and in eight of these its invasion was confined to the mucosa and submucosa. Expression of Bcl-6 was detected in two cases of high-grade MALToma. Only two cases of CD10-positive DLCL had large cell LEL, and seven cases showed tumor invasion beyond the submucosa. All 12 cases were positive for Bcl-6, and a delicate meshwork of CD35 (Ber-MAC-DRC)-positive follicular dendritic cells was detected in eight cases. Pure DLCL of all 17 cases reached the proper muscle layer or more, and expression of Bcl-6 was detected in 10 cases. For patients with pure DLCL, overall survival was significantly (p <0.05) worse than those of high-grade MALToma and CD10-positive DLCL by Kaplan-Meier and log-rank methods. Clinical staging and Bcl-6 expression were also good prognostic factors in patients with DLCL. Three groups of gastric DLCL each had unique histologic findings, immunohistologic characteristics, and prognosis.

Primary gastric B-cell lymphoma: results of a prospective multicenter study. The German-Austrian Gastrointestinal Lymphoma Study Group

BACKGROUND & AIMS

Appropriate management of primary gastric lymphoma is controversial. This prospective, multicenter study aimed to evaluate the accuracy of endoscopic biopsy diagnosis and clinical staging procedures and assess a treatment strategy based on Helicobacter pylori status and tumor stage and grade.

METHODS

Of 266 patients with primary gastric B-cell lymphoma, 236 with stages EI (n = 151) or EII (n = 85) were included in an intention-to-treat analysis. Patients with H. pylori-positive stage EI low-grade lymphoma underwent eradication therapy. Nonresponders and patients with stage EII low-grade lymphoma underwent gastric surgery. Depending on the residual tumor status and predefined risk factors, patients received either radiotherapy or no further treatment. Patients with high-grade lymphoma underwent surgery and chemotherapy at stages EI/EII, complemented by radiation in case of incomplete resection.

RESULTS

Endoscopic-bioptic typing and grading and clinical staging were accurate to 73% and 70%, respectively, based on the histopathology of resected specimens. The overall 2-year survival rates for low-grade lymphoma did not differ in the risk-adjusted treatment groups, ranging from 89% to 96%. In high-grade lymphoma, patients with complete resection or microscopic tumor residuals had significantly better survival rates (88% for EI and 83% for EII) than those with macroscopic tumor residues (53%; P < 0.001).

CONCLUSIONS

There is a considerable need for improvement in clinical diagnostic and staging procedures, especially with a view toward nonsurgical treatment. With the exception of eradication therapy in H. pylori-positive low-grade lymphoma of stage EI and the subgroup of locally advanced high-grade lymphoma, resection remains the treatment of choice. However, because there is an increasing trend toward stomach-conserving therapy, a randomized trial comparing cure of disease and quality of life with surgical and conservative treatment is needed.

Relapse of low-grade gastric MALT lymphoma after Helicobacter pylori eradication: true relapse or persistence? Long-term post-treatment follow-up of a multicenter trial in the north-east of Italy and evaluation of the diagnostic protocol's adequacy

The effect of eradication of Helicobacter pylori on early stage gastric low-grade MALT lymphoma in 76 patients with follow-up of at least 1 year (12-63 months, mean 28) is reported. No regression was found in five cases after 12-48 months. In one case surgical resection detected the involvement of perigastric lymph nodes overlooked by endoscopic ultrasonography (EUS). Neither progression of the disease nor a high-grade component was documented by repeated gastric mappings, EUS and complete stagings in the other four cases. After histological remission five relapses of low-grade and one relapse of high-grade MALT lymphoma were found 12-48 months after eradication. Subsequent histological remission, without any additional therapy, was found in three relapsed cases. A rapid and persistent histological remission was obtained in 56 patients (73%). A late remission was observed in six cases. Monoclonal remission was found in half of the patients and was frequently delayed. Persistent monoclonality was associated with histological remission in the vast majority of patients. Our data confirm H. pylori eradication as the first choice therapy for early stage gastric low-grade MALT lymphoma and recommend extensive bioptic mapping and endoscopic sonography both in the local staging and in the regression evaluation. The rare cases of late remission encourage us to wait for at least 1 year after eradication of H. pylori. Longer follow-up studies will clarify the meaning of histological relapse/persistence and late remission. The study of non-responder cases could show us a step in lymphomagenesis.

Gastric lymphomas in Turkey. Analysis of prognostic factors with special emphasis on flow cytometric DNA content

BACKGROUND

In contrast to DNA ploidy, to the authors' knowledge the prognostic significance of S-phase fraction (SPF) in gastric lymphomas has not been determined. In the current study, the prognostic significance of various parameters including SPF and DNA aneuploidy were analyzed and some distinct epidemiologic and biologic features of gastric lymphomas in Turkey were found.

METHODS

A series of 78 gastric lymphoma patients followed at Hacettepe University is reported. DNA flow cytometry was performed for 34 patients. The influence of various parameters on survival was investigated with the log rank test. The Cox proportional hazards model was fitted to identify independent prognostic factors.

RESULTS

The median age of the patients was 50 years. There was no correlation between patient age and tumor grade. DNA content analysis revealed 4 of the 34 cases to be aneuploid with DNA index values < 1.0. The mean SPF was 33.5%. In the univariate analysis, surgical resection of the tumor, modified Ann Arbor stage, performance status, response to first-line chemotherapy, lactate dehydrogenase (LDH) level, and SPF were important prognostic factors for disease free survival (DFS). The same parameters, excluding LDH level, were important for determining overall survival (OS). In the multivariate analysis, surgical resection of the tumor, disease stage, performance status, and age were found to be important prognostic factors for OS.

CONCLUSIONS

To the authors' knowledge the current study is the first to demonstrate the prognostic significance of SPF in gastric lymphomas. The distinguishing features of Turkish gastric lymphoma patients are 1) DNA indices of aneuploid cases that all are < 1.0, which is a unique feature; 2) a lower percentage of aneuploid cases; 3) a higher SPF; 4) a younger age distribution; and 5) lack of an age-grade correlation. The authors conclude that gastric lymphomas in Turkey have distinct biologic and epidemiologic characteristics.

Low-grade gastric mucosa-associated lymphoid tissue lymphoma: correlation of radiographic and pathologic findings

PURPOSE

To describe upper gastrointestinal (Gl) examination findings of low-grade gastric mucosa-associated lymphoid tissue (MALT) lymphoma and to correlate them with pathologic examination findings.

MATERIALS AND METHODS

A retrospective review of upper Gl examinations was performed in 25 patients with proved low-grade gastric MALT lymphomas. Upper Gl examinations were reviewed for common findings and most probable diagnosis, and these findings were correlated with pathologic findings in resected specimens in 15 patients.

RESULTS

The common findings at upper Gl examination included mucosal nodularity (n = 13), ulcer (n = 12), rugal thickening (n = 6), mass (n = 4), and enlarged areae gastricae (n = 2). The most probable diagnoses were early gastric carcinoma (n = 7), advanced gastric carcinoma (n = 6), gastritis (n = 9), and lymphoma (n = 3). Of 17 lesions found on resected specimens, six ulcers and two masses were not depicted at barium study. Disorganized convergent rugae projecting to multiple points and vague ulcer margins were present in four and seven lesions, respectively. Multiple ulcers were seen in two patients.

CONCLUSION

Although the common radiographic and pathologic findings observed in low-grade gastric MALT lymphomas were similar to those of gastric carcinomas or gastritis, disorganized convergent rugae, vague ulcer margins, and multiplicity of lesions may be helpful in differentiating them from gastric carcinomas or gastritis.

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).

Clinicopathological features of primary gastric lymphoma

BACKGROUND AND OBJECTIVES

Surgery has been the mainstay of the treatment of primary gastric lymphoma, but the value of surgical treatment needs reevaluation.

METHODS

Thirty-two patients with primary non-Hodgkin B-cell lymphoma of the stomach were examined retrospectively to evaluate prognostic factors and their impact on survival. All patients had undergone abdominal exploration for radical surgery between 1979 and 1992. The prognostic factors in view of survival after treatment were determined with both univariate and multivariate analyses.

RESULTS

The resectability rate was 66% (21/32) and radical resections had been performed on 53% (17/32). The overall median survival was 65 months and the overall 5-year survival was 56%. The 5-year survival rates related to a modified Ann Arbor classification as follows: I 1E, 86%; I 2E, 100%; II 1E, 44%; II 2E, 37%; IIIE, 20%; and IVE, 0%. Univariate analysis using Kaplan-Meier estimates showed that radical surgery, Ann Arbor stage, patient's age, and lymph node involvement were significant prognostic factors. According to Cox proportional regression analysis, only Ann Arbor stage, radical surgery, and age were significant independent variables.

CONCLUSIONS

According to our experience, surgery is still needed for the treatment of primary gastric lymphomas, but the benefits of primary chemotherapy or adjuvant chemotherapy using cytotoxic drugs must be determined in large prospective controlled trials.