B-cell monoclonality is associated with lymphoid follicles in gastritis

Lymphoproliferative Disorders of the Gastrointestinal Tract

CONTEXT

- The diagnosis of gastrointestinal lymphoproliferative disorders can be challenging because of the small size of biopsies and the wide spectrum of lymphoproliferative disorders that may be encountered.

OBJECTIVE

- To review the spectrum of lymphoproliferative disorders involving the gastrointestinal tract, highlighting potential pitfalls.

DATA SOURCES

- Peer-reviewed articles and clinical experience.

CONCLUSIONS

- Interpretation of lymphoid infiltrates in gastrointestinal biopsies requires synthesis of morphologic, immunophenotypic, molecular genetic, and clinical information. Knowledge of indolent lymphoproliferative disorders that may mimic aggressive lymphomas will help in preventing misdiagnoses.

Management of Suspicious Mucosa-Associated Lymphoid Tissue Lymphoma in Gastric Biopsy Specimens Obtained during Screening Endoscopy

It is often difficult to differentiate gastric mucosa-associated lymphoid tissue (MALT) lymphoma from Helicobacter pylori-associated follicular gastritis, and thus, it becomes unclear how to manage these diseases. This study aimed to explore the management strategy for and the long-term outcomes of suspicious gastric MALT lymphoma detected by forceps biopsy during screening upper endoscopy. Between October 2003 and May 2013, consecutive subjects who were diagnosed with suspicious gastric MALT lymphomas by screening endoscopy in a health checkup program in Korea were retrospectively enrolled. Suspicious MALT lymphoma was defined as a Wotherspoon score of 3 or 4 upon pathological evaluation of the biopsy specimen. Of 105,164 subjects who underwent screening endoscopies, 49 patients with suspicious MALT lymphomas who underwent subsequent endoscopy were enrolled. Eight patients received a subsequent endoscopy without H. pylori eradication (subsequent endoscopy only group), and 41 patients received H. pylori eradication first followed by endoscopy (eradication first group). MALT lymphoma development was significantly lower in the eradication first group (2/41, 4.9%) than in the subsequent endoscopy only group (3/8, 37.5%, P = 0.026). Notably, among 35 patients with successful H. pylori eradication, there was only one MALT lymphoma patient (2.9%) in whom complete remission was achieved, and there was no recurrence during a median 45 months of endoscopic follow-up. H. pylori eradication with subsequent endoscopy would be a practical management option for suspicious MALT lymphoma detected in a forceps biopsy specimen obtained during screening upper endoscopy.

Russell body gastritis/duodenitis: a case series and description of immunoglobulin light chain restriction

Russell body esophago-gastro-duodenitis is an unusual form of chronic inflammation, with only 22 cases being reported in PubMed. However, the prevalence and clinical significance remain unknown. This report describes the clinico-pathological characteristics of nine cases of Russell body gastritis (RBG) and one case of Russell body duodentitis (RBD), with nonspecific endoscopic appearance. The Mott cells (plasma cells with Russell bodies) showed κ light chain restriction in eight gastritis cases and λ light chain restriction in the duodentitis case, and there were no histological features that suggested lymphoma. Thus, a diagnosis of monoclonal RBG/RBD was made. Helicobacter pylori infection was found in 55.6% of RBG cases and in the RBD case. And, the clinical follow-up evaluations were uneventful. This report is the first study to describe this benign disease entity with monoclonality on a large-scale basis. In addition, the monoclonality of Mott cells cannot be used as evidence of an existing neoplastic lesion, and taken together, these findings may indicate a reactive process.

Lymphoproliferative disorders of the gastrointestinal tract: a review and pragmatic guide to diagnosis

CONTEXT

The gastrointestinal tract is the most common site of extranodal lymphomas. Although all histologic categories of malignant lymphoma develop in the gastrointestinal tract, large B-cell lymphomas predominate, followed by extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT) type; the latter is especially prevalent in stomach. The acceptance of extranodal marginal zone lymphoma of MALT type as a clinicopathologic entity has reduced the number of cases that formerly were interpreted as florid lymphoid hyperplasia ("pseudolymphoma"). Nonetheless, the distinction of lymphoid hyperplasia from a lymphoma of MALT type in small biopsy specimens remains problematic.

OBJECTIVE

To assess the relevant morphologic, immunologic, molecular, and genetic properties of gastrointestinal lymphomas and to present a feasible tactic for diagnosis, expressly for small biopsy specimens.

DATA SOURCES

Case-derived material and literature review using PubMed (National Library of Medicine).

CONCLUSIONS

Most gastrointestinal lymphomas are readily amenable to an unqualified diagnosis, primarily those cases consisting of monomorphic large cells whether of B- or T-cell lineage, including cases associated with enteropathy. Diagnosis for infiltrates dominated by small lymphocytes remains taxing, as the differential diagnosis embraces not only MALT lymphoma and lymphoid hyperplasia but also mantle cell lymphoma, follicular lymphoma, and chronic lymphocytic leukemia/small lymphocytic lymphoma. Adherence to strict morphologic criteria is the standard for diagnosis, but these criteria should be augmented by immunologic studies together with judicious use of molecular techniques to determine clonality. In establishing a diagnosis of gastric marginal zone lymphoma of MALT type, determination of t(11;18)(q21;q21) status may be required since this translocation has clinical ramifications.

t(11;18)(q21;q21) in extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue in stomach: a study of 48 cases

Gastric extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MZL-MALT) is speculated to be immune mediated and is notable for responding to treatment by Helicobacter pylori eradication. However, the gastric MZL-MALT with t(11;18)(q21;q21) has been shown to be resistant to treatment by H. pylori eradication. We studied the molecular, immunohistochemical, and histological aspects of 48 cases of gastric MZL-MALT and used a reverse transcription real-time PCR assay to assess the presence of a t(11;18)(q21;q21) in formalin-fixed, paraffin-embedded tissue. Florescence in situ hybridization for t(11:18)(q21;q21) was used to confirm the real-time PCR results. Three distinct morphological subtypes were recognized: monocytoid, small lymphocytic, and plasmacytoid. Morphology, immunophenotype, and immunoglobulin heavy chain (IgH) gene rearrangement were correlated with the results of the t(11:18)(q21;q21) assay. Of the 48 analyzed cases, 15 (31%) were positive for t(11;18)(q21;q21) and 33 (69%) were monoclonal for IgH gene rearrangement. Of the 15, 13 (87%) cases with t(11;18)(q21;q21) translocation showed IgH gene rearrangement by PCR. Of the 33 t(11;18)(q21;q21)-negative cases tested, 20 cases (61%) showed IgH gene rearrangement. The 15 t(11;18)(q21;q21) translocation-positive cases had either monocytoid (12 of 15) or small lymphocytic morphology (3 of 15). Aberrant expression of CD43 was observed in 8 of 15 (53%) t(11;18)(q21;q21)-positive cases and 21 of 31 (68%) t(11;18)(q21;q21)-negative cases. Our data show that t(11;18)(q21;q21)-positive MZL-MALTs frequently show monocytoid morphology, less often small lymphocytic morphology, and not purely plasmacytoid morphology. Identification of a t(11;18)(q21;q21) by reverse transcription real-time PCR is highly specific for MZL-MALT and helps in the diagnosis of MZL-MALT. Studying the correlation between this translocation and morphological features may increase our understanding of the role of this translocation in the pathogenesis and the clinical behavior of gastric MZL-MALT.

Lyme disease mimicking central nervous system lymphoma

A 33-year-old male presented with a complaint of intermittently blurred vision and right facial weakness. MRI of the brain and orbits revealed numerous cranial nerve abnormalities. There were no focal brain or spinal cord lesions. Cerebral spinal fluid flow cytometry revealed a monoclonal population of B-lymphoid cells. No other evidence of disease was found. Serum Lyme antibody was reported to be IgM positive. Therapy with ceftriaxone, was followed by improvement in his symptoms. Although flow cytometry is a useful tool in distinguishing malignancy from inflammatory disorders it does not always establish the diagnosis of malignancy by itself.

Mucosa-associated lymphoid tissue (MALT) lymphoma: a practical guide for pathologists

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is the third most common non-Hodgkin lymphoma subtype, accounting for around 6-8% of all non-Hodgkin lymphomas in the Western hemisphere. Although MALT lymphomas are clinically indolent, the disease is typically chronic, requiring long-term clinical surveillance and, often, repeated biopsies. Pathologists thus play a central role in the diagnosis and management of these patients. The optimal diagnosis and management of a MALT lymphoma requires careful integration of morphological, immunohistochemical and molecular information, together with close cooperation with the clinician treating the patient. This review discusses recent developments in the molecular pathogenesis of MALT lymphoma and provides strategies for integrating this information into daily pathological practice.

Clonality analyses in gastric MALT (mucosa-associated lymphoid tissue)

B-cell clonality, assessed by PCR for amplification of the VDJ region of the immunoglobulin heavy chain gene (IgH), is used to support the diagnosis of gastric mucosa-associated lymphoid tissue (MALT) lymphoma (GML). It has also been described in simple gastritis cases, without any histological hint for lymphoma, especially in the presence of lymphoid follicles. We analyzed a randomly selected series of 130 gastric biopsies with histologically described lymphoid follicle formation and investigated these for the prevalence of B-cell clonality using different PCR-based methods to discuss its usefulness in the differential diagnosis of GML. A seminested PCR for the IgH gene was performed and evaluated by agarose gel electrophoresis, GeneScan technique, and melting-curve analysis. The majority of cases revealed histologically chronic active Helicobacter pylori gastritis. Monoclonality was detected in 7.5% (10 of 130) and 7% (9 of 130) of samples using GeneScan technique and melting-curve analysis, respectively. In eight of eight samples investigated, monoclonality was not demonstrated in deeper sections of the same biopsy using GeneScan technique, favoring the diagnosis of a reactive process rather than overt lymphoma. Electrophoresis proved more difficult to interpret and revealed clonal cases in 14% (18 of 130). We conclude that GeneScan technique and melting curve analysis are the methods of choice for clonality analysis in gastric biopsies. Analyses of different deep sections with advanced PCR technology might be the method of choice for future analyses. In our opinion, the question of whether detected monoclonality can be interpreted as malignant lymphoma is still open.

Long-term follow-up of gastric MALT lymphoma after Helicobacter pylori eradication

PURPOSE

Cure of infection induces remissions in most patients with early stage Helicobacter pylori- (Hp) positive gastric MALT (mucosa-associated lymphoid tissue) lymphoma (GML). We tracked the long-term stability of remissions in this prospective, multicenter trial.

PATIENTS AND METHODS

In 120 patients with stage I(1E) disease, we performed sequential endoscopic-bioptic follow-up after Hp eradication and polymerase chain reaction of the rearranged immunoglobulin heavy chain gene. The status of t(11;18) was assessed in 65 patients.

RESULTS

Median follow-up was 75 months (range, one to 116). Five-year survival was 90%. Eighty percent of patients (96 of 120) achieved complete histologic remission (CR). Eighty percent of CRs are in continuous complete histologic remission (CCR). Three percent of CR patients (three of 96) relapsed and were referred for alternative treatment. Seventeen percent of CR patients (16 of 96) showed histologic residual disease (RD) during follow-up; a watch-and-wait strategy was applied, and all entered into a second CR. After a median follow-up of 63 months, 14 of 52 analyzed patients reaching CR showed ongoing B-cell monoclonality. Fifteen percent of GMLs were t(11;18) positive. Both t(11;18) and ongoing monoclonality were associated with a significantly higher risk for no response or relapse (P =.004, P =.007), but also present in patients in CCR. Early gastric cancer was diagnosed in three cases during follow-up.

CONCLUSION

Cure of Hp infection results in CCR in most patients. Histologic RD, B-cell monoclonality, and t(11;18) were present in a considerable number of CR patients. A watch-and-wait strategy is justified when close follow-up is guaranteed.

Molecular analysis of B-cell clonality in Helicobacter pylori gastritis

The aim of our study was to identify PCR-detectable clonal B-cell population in Helicobacter pylori gastritis and assess their relation to the Wotherspoon-Isaacson (W-I) grade for gastric lymphoid infiltrates. Amplified DNA was obtained from thirty four H. pylori positive gastritis dyspeptic patients and thirty four H. pylori negative matched controls. Clonal bands were observed in 6 (2/17 W-I Grade 1, 2/13 W-I Grade 2, and 2/4 W-I Grade 3 lesions) and polyclonal smears in 24 cases (15 W-I Grade 1, 7 W-I Grade 2, and 2 W-I Grade 3). Four additional W-I Grade 2 samples with clonal bands were associated with background polyclonal smear and were not reproducible. Clonal bands were not recorded in controls. B-cell clonality was not related to W-I grades. We conclude that certain H. pylori positive gastritis patients show PCR-detectable monoclonality, which is independent of the W-I grade of gastritis and cannot be taken as evidence of an existing neoplastic lesion.

Lymphocytic gastritis-like T cell lymphoma: molecular evidence of an unusual recurrence

This report describes a patient with a gastric biopsy specimen showing histomorphological and immunohistochemical appearances indistinguishable from those usually present in lymphocytic gastritis, a rare condition of unknown aetiology with a distinctive phenotype. The patient had a history of a biopsy confirmed T cell non-Hodgkin lymphoma at two anatomical sites (bladder and stomach), which was subsequently treated. Molecular analysis of the T cell receptor (TCR) gamma chain gene rearrangements showed a distinct monoclonal T cell population in the bladder and gastric biopsies. The same analysis in the lymphocytic gastritis-like biopsy sample showed a monoclonal population with identical base pair size to that identified in the other specimens. This report highlights the importance of TCR gene rearrangement analysis in the diagnosis of unusual gastric inflammation, and the use of capillary electrophoresis based polymerase chain reaction in the follow up of lymphoproliferative disorders.

The role of molecular studies in lymphoma diagnosis: a review

Lymphoma classification is based on a multiparametric approach to diagnosis, in which clinical features, morphology, immunophenotype, karyotype and molecular characteristics are important to varying degrees. While in most cases, a diagnosis can be confidently established on the basis of morphology and immunophenotype alone, a small proportion of diagnostically difficult cases will rely on molecular studies to enable a definitive diagnosis. This review discusses the various molecular techniques available including Southern blotting (SB), polymerase chain reaction (PCR), fluorescence in situ hybridisation (FISH)--including multicolour-FISH/spectral karyotyping and comparative genomic hybridisation--and also gene expression profiling using cDNA microarray technology. Emphasis is given to the analysis of antigen receptor gene rearrangements and chromosomal translocations as they relate to lymphoma diagnosis and also in the setting of minimal residual disease (MRD) detection and monitoring. Laboratories performing these tests need to have expertise in these areas of testing, and there is a need for greater standardisation of molecular tests. It is important to know the sensitivity and specificity of each test as well as its limitations and the pitfalls in the interpretation of results. Above all, results of molecular testing should never be considered in isolation, and must always be interpreted in the context of clinical and other laboratory data.

Helicobacter pylori and gastric malignancies

Clinical outcomes of Helicobacter pylori infection are diverse and caused by the variability of H. pylori virulence factors, host susceptibility, environmental factors and their interactions. Prospective epidemiological studies have clearly shown the relationship between H. pylori infection and gastric cancer. In addition, studies in animal models such as Mongolian gerbils with or without the addition of low-dose chemical carcinogens demonstrated that H. pylori infection can develop gastric carcinoma. Experimental studies have shown that virulence factors of H. pylori interact with gastric epithelial cell signaling related to carcinogenesis. While the effect of H. pylori eradication on prevention of such tumors in chronic H. pylori carriers is still controversial, progress has been made in therapy especially of gastric lymphoma with well tolerated chemotherapeutic regimen.