Molecular diagnostics in low-grade gastric marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue type after Helicobacter pylori eradication therapy

Extranodal and splenic small B-cell lymphoma

Although almost any non-Hodgkin lymphoma can involve the spleen or an extranodal site as part of more widely disseminated disease, there is a group of small B-cell lymphomas that specifically arise in these locations. These are important to recognise as some appear to have a behaviour and prognosis that is distinct from their nodal counterparts. In addition, there are entities that are specific to extranodal locations (such as extranodal marginal zone lymphoma) and to the red or white pulp of the spleen. In this review, the characteristics of these entities will be presented as well as clues to help distinguish lymphoma from reactive infiltrates in extranodal sites and measure to distinguish between small B-cell lymphomas encountered in the spleen and at extranodal locations.

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.

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.

Clinicopathologic features of surgically resected primary gastric lymphoma

AIM: To analyze the clinicopathologic characteristics of surgically resected gastric lymphoma patients.

METHODS: We retrospectively analyzed 57 surgically resected gastric lymphoma patients, dividing them into 2 subgroups: Low grade MALToma (the LG group), High grade MALToma and Diffuse large B cell lymphoma (the HG group).

RESULTS: The numbers of patients were: 20 in the LG group, 37 in the HG group. The diagnostic rate of gastroscopy was 34.8% at primary diagnosis and 50% including differential diagnoses. The positive rates of H pylori were similar between the 2 groups (68% vs 77%). Multiple lesions were found in 19.3%. The proportion of mucosal and submucosal lesions was 80.0%(16/20) in the LG group, and 24.3%(9/37) in the HG group (P<0.001). Lymph node invasion rates were 10.5%(2/19) in the LG group and 44.1%(15/34) in the HG group (P = 0.031). The numbers of recurred patients were none in the LG group, and 8 in the HG group. By univariant analysis, group (P = 0.024) and TNM stage (stage I, II vs stages III, IV, P = 0.002) were found to be the significant risk factors. There was a tendency of higher recurrence rate in the subtotal gastrectomy group than in the total gastrectomy group (P = 0.50).

CONCLUSION: The HG groups had a more advanced stage and a higher recurrence rate than the LG group. Although there was no difference between subtotal and total gastrectomies, more careful assessments of multiplicities and radical resections with lymph node dissections seem to be needed because of multiplicity and LN invasion even in LG group.

B-cell monoclonality is associated with lymphoid follicles in gastritis

The gold standard for diagnosis of gastric MALT lymphoma is histopathology. Polymerase chain reaction-based assays to detect the expansion of monoclonal B cells have also been used to corroborate the diagnosis. However, there are conflicting data on monoclonal B-cell expansion in gastritis. We asked about its frequency in graded gastritis cases. Lymphocytic infiltration in gastric biopsies was graded according to Wotherspoon in 129 cases. The histologic diagnosis ranged from normal gastric mucosa to suspicious for gastric MALT lymphoma. To search for a monoclonal B-cell population, a semi-nested polymerase chain reaction strategy was used for amplification of rearranged VDJ sequences of the immunoglobulin heavy chain gene. Of 106 evaluable samples, 18 were found to be monoclonal. The detection of a monoclonal B-cell population was strongly associated with the presence of lymphoid follicles. In cases with lymphoid follicles, detection of monoclonality was independent of Wotherspoon grading; there is no significant difference between cases being suspicious for lymphoma and those not. We found B-cell monoclonality to be a more frequent than expected finding in gastritis and to be strongly associated with the presence of lymphoid follicles; thus, its presence is of little significance in patient management.

Clinicopathologic study of mucosa-associated lymphoid tissue lymphoma in gastroscopic biopsy

AIM: To explore and discuss the clinicopathologic characteristics of mucosa-associated lymphoid tissue (MALT) lymphoma in gastroscopic biopsy specimen.

METHODS: A retrospective study of 26 cases of lymphoma diagnosed by gastroscopic biopsy during 1999 to 2001 from gastroscopy files of Xijing Hospital was made. The diagnostic criteria were adopted according to the new classification of non-Hodgkin's lymphoma.

RESULTS: Twenty-six cases of primary gastric lymphoma consisting of 15 men and 11 women, aged between 23 to 76 years were recruited from 6225 cases who received gastroscopy. All of them were diagnosed by both endoscopic findings and histological examinations. Histologically, 23 cases were MALToma (low grade) and 3 cases lymphoblastic lymphoma (high grade). Immunohistochemically, all cases were CD20 positive, while CK and EMA were negative.

CONCLUSION: The majority of the cases of primary low-grade gastric lymphoma have morphologic and clinical features that justify their inclusion in the category of low-grade lymphoma of mucosa associated lymphoid tissue.