Low-grade B-cell Mucosa-associated Lymphoid Tissue Research Articles

A Case Report of Non-Hodgkin Low-grade B-cell Mucosa-associated Lymphoid Tissue Lymphoma Presenting as a Suspected Endodontic Lesion

Extranodal mucosa-associated lymphoid tissue lymphoma is a rare oral disease. This case report describes a 71-year-old woman who presented for endodontic evaluation and treatment for swelling on the right posterior palatal. The case details the evaluation and diagnostic processes and treatment course. The case report draws attention to the importance of performing a biopsy, having proper sampling, and the additional steps sometimes required to arrive at a definitive diagnosis. This case report is the first to document a definitive low-grade B-cell mucosa-associated lymphoid tissue lymphoma mimicking endodontic pathology. The case shows the importance of proper examination, clinical imaging, and pathologic testing to arrive at a definitive diagnosis. It highlights that collaboration with other medical and dental specialties is essential for appropriate diagnosis and treatment and describes the “buttonhole” diagnostic strategy.

Eradication Therapy in Helicobacter pylori-negative, Gastric Low-grade Mucosa–associated Lymphoid Tissue Lymphoma Patients

To assess the remission rate of gastric low-grade B-cell mucosa-associated lymphoid tissue lymphoma after an eradication therapy in Helicobacter pylori-negative patients. We performed a systematic review with pooled analysis of published studies. Data were analyzed according to: (1) number of H. pylori-negative patients treated with only eradication therapy; (2) number of patients in whom the complete lymphoma remission was achieved; and (3) the method used to exclude H. pylori infection. Overall, 11 studies with 110 patients met the inclusion criteria for this pooled analysis. H. pylori infection was excluded in all studies with at least 3 different diagnostic tests. Eradication therapy achieved a complete lymphoma regression in 17 (15.5%; 95% confidence interval, 8.7-22.2) patients. Eradication therapy is successful in a small but distinct subgroup of H. pylori-negative patients with low-grade mucosa-associated lymphoid tissue lymphoma. On the basis of the generally indolent behavior of this neoplasia, before resorting to aggressive, costly, and potentially more toxic oncologic therapies, it would seem reasonable to attempt eradication therapy in all patients, irrespective of their H. pylori status.

Imaging findings of a primary bladder maltoma

Secondary involvement of the urinary bladder in non-Hodgkin's lymphoma is relatively common; however, primary malignant lymphoma of this organ is extremely rare. The most common type of primary bladder lymphoma is a low-grade B-cell mucosa-associated lymphoid tissue (MALT) lymphoma. We report here on the imaging findings of a primary bladder lymphoma with bone marrow infiltration.

Multiplex-Touchdown PCR Assay for the Detection and Genotyping of Helicobacter pylori from Artificially Contaminated Sheep Milk

Helicobacter pylori (Hp) is an organism commonly present worldwide in the human population, sometimes causing serious illnesses such as duodenal and gastric ulcers, adenocarcinoma of the stomach, and low-grade B-cell mucosa-associated lymphoid tissue lymphoma of the stomach. This article describes a multiplex-touchdown PCR method for the identification and genotyping (vacA—s1/m1, s1/m2, and s2/m2—and cagA genes) of Hp directly from sheep milk artificially contaminated with Hp strains from human gastric biopsies and with Hp ATCC 43504. The strains from humans carried s1/m2 cagA+ and s2/m2 cagA− allelic combinations, while the ATCC strains carried an s1/m1 cagA+ allelic combination. The technique showed a sensitivity of 15 CFU/ml for species identification and of 1,500 CFU/ml for the detection of genes encoding for VacA and CagA. It has proven to be specific and rapid, and the authors suggest that it be used as a rapid screening method to ensure that sheep milk is uncontaminated with this organism.

Loss of Expression of α4β7 Integrin and L-selectin Is Associated with High-Grade Progression of Low-Grade MALT Lymphoma

Expression of adhesion molecule in low-grade B-cell mucosa-associated lymphoid tissue (MALT) lymphoma of the gastrointestinal tract has been reported in recent years, but these reports have primarily focused on low-grade gastrointestinal MALT lymphoma. In this study, we examined the lymphocytic homing receptor α4β7 integrin, L-selectin, and VLA-4 and mucosal addressin cell adhesion molecule-1 (MAdCAM-1) in low-grade lymphoma of the gastrointestinal tract and other organs such as the ocular adnexa and thyroid. We also observed changes in the expression pattern associated with high-grade transformation. Neoplastic cells in the gastrointestinal low-grade lymphoma and the low-grade component of high-grade MALT lymphoma were found to be α4β7 integrin+, L-selectin+, whereas the gastrointestinal high-grade component and diffuse large B-cell lymphoma were found to be α4β7 integrin−, L-selectin−. High endothelial venules in the gastric MALT lymphomas expressed MAdCAM-1. In the ocular adnexa low-grade MALT lymphoma, most cases were α4β7 integrin−, L-selectin+; and in the thyroid, most cases of both low- and high-grade MALT lymphoma were α4β7 integrin−, L-selectin−. These findings show that α4β7 integrin and L-selectin may play an important role in the lymphocyte homing of gastrointestinal low-grade MALT lymphoma and in the loss of α4β7 integrin expression throughout the course of high-grade progression.

Extranodal marginal-zone B-cell lymphoma of the salivary gland.

Primary non-Hodgkin's lymphoma of the salivary gland is an uncommon tumor that most often occurs in the parotid gland. The most common subtype is marginal-zone B-cell lymphoma, extranodal, mucosa-associated lymphoid tissue type. This subtype has recently been included in the Revised European-American Classification of Lymphoid Neoplasms, as well as in the upcoming World Health Organization classification of hematopoietic and lymphoid neoplasms. This low-grade lymphoma usually arises in a background of benign lymphoepithelial lesion or myoepithelial sialadenitis that is associated with the autoimmune disease Sjögren's syndrome. It occasionally develops in patients who do not have a history of autoimmune disease. When mucosa-associated lymphoid tissue lymphoma occurs in the salivary gland, as in other extranodal sites such as the stomach, it is usually an indolent neoplasm that tends to remain localized for long periods of time, even without treatment. Eventually, however, the tumor may disseminate or transform to a higher grade. The histologic distinction of myoepithelial sialadenitis from low-grade B-cell mucosa-associated lymphoid tissue lymphoma can be a difficult diagnostic challenge and many of these lesions continue to be ambiguously diagnosed as "pseudolymphoma." Immunophenotypic or flow cytometric analysis may be useful in showing an aberrant phenotype or immunoglobulin light-chain restriction, which helps to support a diagnosis of malignant lymphoma in most cases. Molecular genetic analysis for immunoglobulin gene rearrangements also may be useful in showing monoclonality, although the exact significance of this finding in some cases remains controversial.

Prospective long-term endoscopic and histologic follow-up of gastric lymphoproliferative disease of early stage IE low-grade B-cell mucosa-associated lymphoid tissue type following Helicobacter pylori eradication treatment.

Long-term endoscopic and histologic follow-up of Stage IE gastric lymphoproliferative disease of the low-grade B-cell mucosa-associated lymphoid tissue (MALT) type following cure of H. pylori was undertaken. Clinical and endoscopic features (age, race, endoscopic appearance, cure of H. pylori and duration of follow-up) were also evaluated as potential prognostic indicators for complete or near-complete regression of low-grade MALT lymphoma. Sixty-eight MALT lymphoma patients prospectively underwent H. pylori eradication. follow-up at periodic intervals with endoscopy and extensive mucosal biopsy protocol on 65 patients ranging from 12 weeks up to 73 months (mean +/- SD of 22.5+/-15.8 months) has been completed. H. pylori was eradicated in 89.2% of MALT lymphoma patients with complete histologic regression noted in 58.5%, near-complete regression in 18.5%, partial in 4.6%, and no change in 18.5%. Univariate analysis revealed two factors predictive of complete and/or near complete MALT lymphoma regression, H. pylori cure (p=0. 001) and duration of follow-up (p=0.001). Stepwise logistic regression also demonstrated that both H. pylori cure (p<0.0001) and duration of follow-up (p<0.02) were independently associated with complete and near complete MALT lymphoma regression. Age, race, and endoscopic appearance were not predictive of regression. We conclude that this lymphoproliferative disease predictably undergoes complete to near-complete histologic regression at variable rates following cure of H. pylori in a majority of patients.

Efficacy of single-agent chemotherapy in low-grade B-cell mucosa-associated lymphoid tissue lymphoma with prominent gastric expression.

The treatment of low-grade B-cell mucosa-associated lymphoid tissue (MALT) lymphoma with prominent gastric expression is controversial. Total gastrectomy has been proposed, but is associated with significant morbidity. The aim of this monocentric study was to assess the efficacy of continuous oral chemotherapy with a single alkylating agent. Twenty-four consecutive patients, 13 men and 11 women, were studied. Their mean age was 51 years (range, 22 to 79). Low-grade B-cell MALT lymphoma was diagnosed by histologic and immunohistologic examination of endoscopic biopsies. Seventeen patients had stage I disease and seven stage IV disease, with lung and gastric involvement. Two of these seven patients also had bone marrow involvement. The alkylating agent (cyclophosphamide or chlorambucil) was administered orally and daily for periods of 12 to 24 months. The median follow-up time was 45 months (range, 14 months to 14 years). Complete remission was obtained in 18 patients (75%) after a median treatment duration of 12 months. Five patients relapsed; two of them were successfully re-treated, and one died of MALT lymphoma that had transformed into large-cell lymphoma. Chemotherapy was stopped after 24 months for six patients who only achieved a partial remission; two of them required further treatment for progressive disease (surgery for a small-bowel localization in one case and cyclophosphamide rechallenge in the other). Nine patients had neutropenia that required a reduced chemotherapy dosage. In low-grade MALT lymphoma with prominent gastric expression, continuous monochemotherapy may constitute an efficient alternative to gastrectomy, regardless of disease stage.

ＭＡＬＴリンパ腫

The distinctive low-grade B-cell mucosa-associated lymphoid tissue lymphoma (MALToma) of the extranodal lymphoid tissue has been well characterized in recent years. One hundred cases of gastrectomized primary gastric lymphomas, 30 cases of surgically resected primary intestinal lymphomas and five cases of autopsied pulmonary lymphomas were examined clinicopathologically. Fortyone cases of gastric lymphomas, nine cases of intestinal lymphomas and four cases of pulmonary lymphomas were classified as MALToma by using Isaacson's classification. Morphological feature of MALToma was lymphoepithelial lesion. All of gastric MALTomas were found out in advanced stage. Pulmonary lymphoma cases were not diagnosed correctly during life. Metastasis in gastrointestinal tract and serous membrane were seen in four cases of pulmonary MALToma. Tumor cells of MALTomas share an identical phenotype with splenic marginal zone B-cells. We examined the experimental gastric ulcer of rat by using immunohistochemistry. Centrocyte-like cells foci were observed in the ulcer bed, which express the phenotypical characters as same as splenic marginal zone B-cells. We discussed the cytopathological features of MALToma from the viewpoint of B-cell lineages.