Primary low-grade gastric mucosa-associated lymphoid tissue (MALT) lymphoma with polypoid appearance. Polypoid gastric MALT lymphoma: A clinicopathologic study of eight cases

Correlation of Endoscopic Findings of Gastric Mucosa-Associated Lymphoid Tissue Lymphoma with Recurrence after Complete Remission

Background/Aims

In gastric mucosa-associated lymphoid tissue (MALT) lymphoma, the clinical significance of various endoscopic findings has not yet been determined. This study aimed to compare the time to complete remission (CR) and relapse-free survival (RFS) in gastric MALT lymphoma based on endoscopic findings.

Methods

In this single-center retrospective cohort study, the medical records of 122 consecutive adult patients with gastric MALT lymphoma were collected over a period of 12 years. CR was defined by the absence of macroscopic or microscopic features of lymphoma on two subsequent follow-ups. Relapse was clinically defined by a positive endoscopic biopsy after CR.

Results

The median time to CR did not differ significantly between treatment methods. However, it was significantly longer in the group with polypoid endoscopic appearance than in the groups with diffuse infiltration or ulceration (7.83, 3.43, and 3.10 months, respectively; p=0.003). Six patients relapsed after CR. Kaplan-Meier analysis showed that RFS differed significantly between groups based on Ann Arbor staging, treatment methods, and initial endoscopic findings.

Conclusions

In gastric MALT lymphoma, the endoscopically defined polypoid type was characterized by a longer duration to CR, with a higher likelihood of recurrence, compared to the endoscopically defined diffuse infiltration or ulceration types.

Extranodal lymphoma

Lymphomas arising in extranodal sites are intriguing. The types of lymphomas encountered vary widely from one extranodal site to another. For many types of extranodal lymphomas, there are distinctive clinicopathologic features, sometimes including association with an underlying immunodeficiency syndrome, autoimmune disease, infection, or other immunologic disorder, or a predilection to affect patients of certain ethnic origins. Presented below is a review of lymphomas that are encountered most often in extranodal sites.

Autopsy case of lymphoplasmacytic lymphoma with a large submucosal tumor in the stomach

An autopsy case of lymphoplasmacytic lymphoma with a large submucosal tumor in the stomach is presented. The patient was a 77-year-old woman with gastric lymphoma associated with Waldenstrom's macroglobulinemia of IgM-lambda type. Diagnosis was initially mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach, because gastric biopsy specimens showed epitheliotropic proliferation (lymphoepithelial lesion) of the lymphoma cells. Postmortem examination revealed a large gastric lymphoma with metastatic foci in the esophagus, larynx, trachea, lungs, spleen and lymph nodes. The bone marrow was also involved. Lymphoma cells consisted of small lymphocytoid cells occasionally admixed with blast-like large cells and a large number of plasmacytoid or plasma cells. Centrocyte-like cells were not found. Lymphoepithelial lesions were not conspicuous in autopsy specimens. Immunohistochemically, lymphoma cells reacted with CD20, CD45, CD79a, anti-IgM, anti-lambda protein and anti-BCL-2, but not with CD5, CD10, CD23 or CD38. Based on these findings, the revised diagnosis of the present case was lymphoplasmacytic lymphoma, and it highlighted the differential diagnostic problem from marginal zone B-cell lymphoma of MALT type.

Helicobacter pylori and the t(11;18)(q21;q21) translocation in gastric low-grade B-cell lymphoma of mucosa-associated lymphoid tissue type

The reported regression of mucosa-associated lymphoid tissue (MALT) type gastric low-grade B-cell lymphoma following treatment for Helicobacter pylori (H. pylori) infection has not yet been comprehensively analyzed, especially in relation to the recently identified c-IAP2-MALT1 / MLT gene alteration resulting from the t(11;18)(q21;q21) chromosomal translocation found in MALT lymphoma. The relationship between MALT lymphomas and H. pylori was investigated in 30 patients who received an antibacterial treatment. Patients were followed up by means of endoscopy and biopsy. Molecular genetic analyses focused on the presence or absence of the immunoglobulin heavy chain (IgH) gene and / or MALT1 / MLT gene alteration resulting from t(11;18)(q21;q21) translocation. H. pylori was positive in 26 of the 30 patients. The overall success rate of cure of H. pylori infection was 96% (25 / 26). Thirteen patients (52%) showed complete remission (CR) of lymphoma, nine (36%) partial remission (PR), and three (12%) registered no change (NC). Statistical analysis revealed significant differences between CR and PR / NC patients in age ( < 60 or 60), in lymphoma location (single or multiple sites) and in the presence or absence of gene rearrangement before eradication (P < 0.05). Endoscopy showed a cobblestone appearance only in PR cases and polypoid features predominantly in NC cases. Two NC patients with polypoid gross appearance showed rearrangements involving either c-IAP2 or MALT1 gene in Southern blot analysis, while none of seven other resected patients with non-polypoid superficial gross appearance showed rearrangement. Gastric MALT lymphoma could be pragmatically subdivided into three groups, CR (MALT-A), PR (MALT-B), and NC (MALT-C) on the basis of the reaction to eradication of H. pylori. We speculate that MALT-A may represent an incipient neoplasm or dysplasia, MALT-B a neoplasm activated by antigenic stimulation of H. pylori, and MALT-C a lymphoma independent of H. pylori. Polypoid lesions in MALT-C were associated with c-IAP2-MALT1 / MLT gene alteration resulting from t(11;18)(q21;q21). This classification is thought to be clinically significant for deciding the most appropriate mode of treatment of MALT-type lymphoproliferative disorders.