Clonal relationship of extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue involving different sites

Marginal zone lymphoma of extranodal sites: A review with an emphasis on diagnostic pitfalls and differential diagnosis with reactive conditions

Marginal zone lymphoma of the mucosa-associated lymphoid tissue (MALT lymphoma) represents 8% of all B-cell lymphomas and it is the most common small B-cell lymphoma arising at extranodal sites. The gold-standard test to establish a diagnosis of MALT lymphoma remains histopathologic analysis with the aid of immunohistochemistry (IHC) and/or flow cytometry immunophenotypic analysis. MALT lymphoma represents a progression from a persistent chronic inflammatory process, and therefore distinguishing MALT lymphoma from chronic inflammation by histopathology may be challenging in some cases. Despite recent trends to consider IGH rearrangement/clonality as a confirmatory diagnostic test of MALT lymphoma, this method is far from ideal for this purpose since a positive or a negative result does not necessarily confirm or exclude that a process is lymphoma or reactive. This test must be correlated with the morphologic findings. Moreover, MALT lymphoma may arise in association with underlying autoimmune conditions where clonal lymphoid populations are not uncommonly detected. Therefore, we believe that an integrated approach including detailed morphologic review in combination with IHC and/or flow cytometry is best to establish a diagnosis of MALT lymphoma in most cases. We present helpful morphologic tips to avoid potential diagnostic pitfalls at some of the most common extranodal sites, including the stomach, ocular adnexa/conjunctiva, salivary gland, lung, thymus, breast, thyroid, small and large intestine and the dura. The differential diagnosis of MALT lymphoma with IgG4-related disease is also discussed.

The usefulness of serial ultrasound in thyroid mucosa-associated lymphoid tissue lymphoma

BACKGROUND

Mucosa-associated lymphoid tissue (MALT) lymphoma is an extranodal lymphoma with an indolent natural course. The thyroid gland is an uncommon site of involvement. We aimed to investigate serial ultrasound features and the disease progression during the clinical course of thyroid MALT lymphoma.

METHODS

We searched our hospital's pathology database (5,418 patients with thyroid malignancy) between January 2000 and July 2022. The medical records and serial ultrasounds of 11 patients with 12 thyroid MALT lymphoma foci were analyzed retrospectively.

RESULTS

An enlarging neck mass, dyspnea, B symptoms, and neck lymphadenopathy were seen at diagnosis in 9 (9/11, 81.8%), 3 (3/11, 27.3%), 2 (2/11, 18.2%), and 9 (9/11, 81.8%) cases, respectively. Eleven cases were concomitant Hashimoto thyroiditis. Common ultrasound features included bilateral or unilateral asymmetric goiter or large, solid, and very hypoechoic nodules (11/12, 91.7%) interspersed with linear, reticular hyperechoic, and enhanced posterior echoes (11/12, 91.7%), and neck lymph node involvement (10/11, 90.9%). The Thyroid Imaging and Reporting Data System (TIRADS) categories showed higher diagnostic accuracy (11/12, 91.7%) than real-time ultrasound (2/12, 16.7%) in evaluating thyroid lesions for recommendation of fine-needle aspiration (FNA). Serial ultrasound showed self-limiting changes in three cases, relapse in three cases after subtotal thyroidectomy and chemotherapy, large cell transformation (LCT) in one case after left lobectomy, partial remission in one case, and complete remission after chemo/radiation in four cases; progression to enlarged thyroid nodules occurred in three cases without treatment, with no obvious change observed after diagnosis. Three patients died during follow-up.

CONCLUSION

On sonograms, solid large thyroid nodules or goiter with very hypoechoic and enhanced posterior echoes in the setting of Hashimoto thyroiditis should raise suspicion for MALT lymphoma. TIRADS categories can improve the ultrasound diagnostic efficacy for malignancy. Serial ultrasound examinations demonstrated self-limiting and indolent natures of thyroid MALT lymphoma.

Primary Nondural Central Nervous System Marginal ZoneB-Cell Lymphoma of the Mucosa-Associated Lymphoid Tissue Type Mimicking CNS Inflammatory Diseases

Marginal zone B-cell lymphomas (MZBCLs) are non-Hodgkin lymphomas arising from postgerminal center marginal zone B cells. MZBCLs are subclassified into extranodal, nodal, and splenic MZBCLs. Primary nondural central nervous system (CNS) MZBCLs of the mucosa-associated lymphoid tissue (MALT) type are among the extranodal examples. Their clinicopathological features are not well characterized. Therefore, the clinicopathological features of 8 primary nondural CNS MZBCLs of the MALT type were assessed to establish their pathological diagnostic criteria. Histologically, all cases of primary nondural CNS MZBCLs of the MALT type showed perivascular expansive monotonous proliferation of small atypical B lymphoid cells with plasma cell differentiation, low Ki-67 labeling index, and minimal invasion from the perivascular space. In addition, no vascular changes such as glomeruloid changes, obliterative fibrointimal proliferation, and intramural lymphocytic infiltration were seen. These key histological characteristics should be considered when diagnosing cases that are suspected to be primary nondural CNS MZBCLs of the MALT type. Additionally, regarding PCR for the detection of immunoglobulin heavy variable gene and T-cell receptor γ gene rearrangements, the former is detected, but the latter is not detected in all cases. Therefore, PCR detection including sequence analysis should be added when diagnosing difficult cases based on the key histological characteristics.

Clonal relationship in multisited mucosa-associated lymphoid tissue lymphomas: a single-centre experience

Clonal heterogeneity in multisited or recurrent lymphoid neoplasms is a phenomenon that has been increasingly studied in recent years. However, in mucosa-associated lymphoid tissue (MALT) lymphomas it remains largely unexplored. Patients diagnosed at our institution with multisited MALT lymphoma, from January 2009 to October 2018, were studied. Molecular studies were performed for the detection of clonally rearranged immunoglobulin by polymerase chain reaction.In all, 91 patients were included. Of those, 28 had a multisited disease and in 16 clonality studies were done. In eight cases, multifocal involvement was synchronous and in eight metachronous. Patients with non-gastric gastrointestinal tract involvement tended to disseminate within the same tract, without observing other specific dissemination patterns. Four cases (25%) had clonal heterogeneity at the different organs involved. All patients with late relapses (two patients) had different clones. The majority of patients with multisited MALT lymphomas presented with the same clone in the different involved organs, identifying a different clone in those with late relapses. These patients could represent de novo neoplasms, rather than a relapse. This could mean that some individuals might have a genetic predisposition to develop this type of lymphoma and it could also have clinical implications regarding therapeutic decisions.

Marginal zone B-cell lymphoma: lessons from Western and Eastern diagnostic approaches

Marginal zone B-cell lymphomas (MZLs) are a group of clinically indolent B-cell lymphomas postulated to derive from memory B lymphocytes in the 'marginal zone' of secondary lymphoid tissue. Today, MZL is recognised as a nosological umbrella term encompassing distinct entities with some shared phenotypic and genotypic features, including extranodal marginal zone B-cell lymphoma (EMZL) or mucosa-associated lymphoid tissue (MALT) lymphoma, splenic MZL, and nodal MZL, accounting for approximately 70%, 20%, and 10% of MZLs, respectively. These lymphomas share some phenotypic and genotypic features and have some variants and related provisional diseases, but are different in regards to their clinical and molecular characteristics. In addition, they are frequently associated with chronic antigenic stimulation represented either by infectious agents, particularly bacteria and viruses, or autoimmune diseases as exemplified by Sjögren syndrome, Hashimoto thyroiditis, and newly recognised IgG4-related disease. Furthermore, several chromosomal translocations have been identified in EMZL. In this review, we will focus on the updated histopathological criteria and the main problems with differential diagnoses in order to aid the diagnostic approach in our routine practice.

Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue in the oromaxillofacial head and neck region: A retrospective analysis of 105 patients

Background

Extranodal marginal zone B‐cell lymphoma of mucosa‐associated lymphoid tissue (MALT lymphoma) in the oromaxillofacial head and neck region is rare, with limited data available. This retrospective study explored the clinical features, stage, treatment, and prognosis of this disease.

Methods

Overall, 105 patients with MALT lymphomas in the oromaxillofacial head and neck region were included in this retrospective analysis. SPSS 22.0 software package was used for data analysis and a two‐tailed P value of ≤.05 was considered statistically significant. Primary endpoints of the study were the complete response (CR) rate, overall survival (OS), and progression‐free survival (PFS).

Results

About 52% of the patients had long‐term xerostomia, autoimmune diseases, or chronic parotitis and 81% had diseases involving the large salivary glands. Ann Arbor staging of the patients was as follows: stages I/II, 73 patients and stages III/IV, 32 patients. In the 97 patients followed up, CR rate after initial treatment was 80%. Tumor progression was observed in 12 patients and 14 patients died. There was a significant difference between the rate of CR in localized (87%) and disseminated (67%) lymphoma patients (P = .02). The 5‐ and 10‐year PFS of the localized lymphoma patients were both 91%, whereas those of the disseminated lymphoma patients were 83% and 65%, respectively (P = .03). The 5‐year PFS rates of the chemotherapy and non‐chemotherapy groups in the disseminated lymphoma patients were 85% and 73% (P = .04). Meanwhile, the 5‐year PFS rates of the rituximab and non‐rituximab groups in the disseminated lymphoma patients were 100% and 70% (P = .03). In multivariate analysis, MALT Lymphoma International Prognostic Index (MALT‐IPI) was an independent prognostic factor affecting OS, whereas Ann Arbor staging affected PFS.

Conclusions

This study suggests that the outcome after initial treatment of MALT lymphomas in the oromaxillofacial head and neck region is satisfactory and that this disease progresses slowly. The CR rate and PFS of localized lymphoma patients are better than those of disseminated lymphoma patients. Systemic treatment (chemotherapy or rituximab) may improve PFS in disseminated disease patients. MALT‐IPI and Ann Arbor staging are independent prognostic factors.

Mucosa-associated lymphoid tissue lymphoma with metachronous involvement of the palpebral conjunctiva and bronchus: A case report

A 61-year-old woman with a history of palpebral conjunctival mucosa-associated lymphoid tissue (MALT) lymphoma, treated with rituximab, was referred to the authors' hospital after follow-up positron emission tomography/computed tomography revealed ¹⁸F-fluoro-2-deoxy-d-glucose uptake in a tumor located in the left main bronchus. The diagnosis of MALT lymphoma was made by pathological and immunohistochemical findings homologous to previous palpebral conjunctival lesion via bronchoscopic biopsy. The disease was controlled with rituximab, cyclophosphamide, oncovin, and prednisolone (i.e., R-COP) chemotherapy. Although MALT lymphoma occurs in several organs, metachronous occurrence in the palpebral conjunctiva and bronchus is especially rare, and careful check-up is required to monitor for occurrence of systemic relapse.

Simultaneous Occurrence of Colonic Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma (MALToma) and Lung Cancer

Colonic MALToma accounts for 2.5% of all MALTomas. MALToma can be associated with certain chronic infections, autoimmune disorders, Waldenstrom's macroglobulinemia, and old age. Synchronous MALTomas can occur in multiple organs. Simultaneous occurrence of colonic MALToma and colon cancer has been reported. A case of colonic MALToma and lung cancer is described here.

Evaluation of the diagnostic value of immunoglobulin clonal gene rearrangements in patients with parotid gland MALT lymphoma using BIOMED-2 protocol

OBJECTIVES

The aim of this study was to evaluate the diagnostic value of immunoglobulin (Ig) clonal gene rearrangements for mucosa-associated lymphoid tissue (MALT) lymphoma of the parotid gland.

STUDY DESIGN

We collected and retrospectively analyzed clinical data of 21 patients referred to our institution between 2009 and 2017. Eight patients had been primarily diagnosed MALT lymphoma of the parotid gland and the remaining patients with lymphoepithelial lesion. Paraffin-embedded tissues were chosen for extracting genomic DNA and multiplex primer polymerase chain reaction amplification by using BIOMED-2 primers. Polymerase chain reaction amplification products were analyzed by heteroduplex analysis.

RESULTS

Generally, 17 patients were identified to have parotid gland MALT lymphoma; 47.06% of them had Sjögren syndrome. The sensitivity of IGH VH-J_H FR1, FR2, FR3, IGK Vκ-Jκ, and IGK (Vκ-Kde and intron-Kde) as targets was 76.47%, 82.35%, 88.24%, 29.41%, and 35.29%, respectively. The sensitivity of combined application of the above-mentioned 3 IGH primers as targets was 100%. The sensitivity of combined application of the above two IGK primers as targets was 58.82%.

CONCLUSIONS

Ig clonal gene rearrangements assays using BIOMED-2 protocol can be a highly reliable diagnostic method for parotid gland MALT lymphoma. For patients with Sjögren syndrome along with histologically benign lymphoepithelial lesion, identification of Ig clonal gene rearrangements is important for routine differential diagnosis.

Concurrent gastric and pulmonary mucosa-associated lymphoid tissue lymphomas with pre-existing intrinsic chronic inflammation: a case report and a review of the literature

Herein, we report a rare case of concurrent gastric and pulmonary mucosa-associated lymphoid tissue (MALT) lymphomas. A 65-year-old man who had been diagnosed with Helicobacter pylori-positive gastric MALT lymphoma received eradication therapy and achieved complete remission. During follow-up, he developed de novo pulmonary MALT lymphoma as a sequela of pulmonary tuberculosis, accompanied by recurrent gastric MALT lymphoma. Polymerase chain reaction (PCR) products of the CDR3 region of the immunoglobulin heavy chain gene showed an overall polyclonal pattern with bands at 400 base pairs (bp) and 200 bp predominant in the pulmonary tissue, as well as two distinctive bands in the gastric tissue at 400 bp and 200 bp. This case suggests that multiorgan lymphomas are more likely to be independent from each other when they are far apart, involve different organ systems, and have independent precipitating factors.

Molecular and cytogenetic characterization of expanded B-cell clones from multiclonal versus monoclonal B-cell chronic lymphoproliferative disorders

Chronic antigen-stimulation has been recurrently involved in the earlier stages of monoclonal B-cell lymphocytosis, chronic lymphocytic leukemia and other B-cell chronic lymphoproliferative disorders. The expansion of two or more B-cell clones has frequently been reported in individuals with these conditions; potentially, such coexisting clones have a greater probability of interaction with common immunological determinants. Here, we analyzed the B-cell receptor repertoire and molecular profile, as well as the phenotypic, cytogenetic and hematologic features, of 228 chronic lymphocytic leukemia-like and non-chronic lymphocytic leukemia-like clones comparing multiclonal (n=85 clones from 41 cases) versus monoclonal (n=143 clones) monoclonal B-cell lymphocytosis, chronic lymphocytic leukemia and other B-cell chronic lymphoproliferative disorders. The B-cell receptor of B-cell clones from multiclonal cases showed a slightly higher degree of HCDR3 homology than B-cell clones from mono clonal cases, in association with unique hematologic (e.g. lower B-lymphocyte counts) and cytogenetic (e.g. lower frequency of cytogenetically altered clones) features usually related to earlier stages of the disease. Moreover, a subgroup of coexisting B-cell clones from individual multiclonal cases which were found to be phylogenetically related showed unique molecular and cytogenetic features: they more frequently shared IGHV3 gene usage, shorter HCDR3 sequences with a greater proportion of IGHV mutations and del(13q14.3), than other unrelated B-cell clones. These results would support the antigen-driven nature of such multiclonal B-cell expansions, with potential involvement of multiple antigens/epitopes.

Role of Helicobacter pylori in gastric mucosa-associated lymphoid tissue lymphomas

Mucosa-associated lymphoid tissue (MALT) lymphoma is an indolent extranodal marginal zone B-cell lymphoma, originating in acquired MALT that is induced in mucosal barriers as part of a normal adaptive immune response to a chronic immunoinflammatory stimulus, most notably chronic infection by Helicobacter pylori (H. pylori). This antigenic stimulation initially leads to lymphoid hyperplasia; the acquisition of additional genetic aberrations culminates in the activation of intracellular survival pathways, with disease progression due to proliferation and resistance to apoptosis, and the emergence of a malignant clone. There are descriptions of MALT lymphomas affecting practically every organ and system, with a marked geographic variability partially attributable to the epidemiology of the underlying risk factors; nevertheless, the digestive system (and predominantly the stomach) is the most frequently involved location, reflecting the gastrointestinal tract’s unique characteristics of contact with foreign antigens, high mucosal permeability, large extension and intrinsic lymphoid system. While early-stage gastric MALT lymphoma can frequently regress after the therapeutic reversal of the chronic immune stimulus through antibiotic eradication of H. pylori infection, the presence of immortalizing genetic abnormalities, of advanced disease or of eradication-refractoriness requires a more aggressive approach which is, presently, not consensual. The fact that MALT lymphomas are rare neoplasms, with a worldwide incidence of 1-1.5 cases per 10⁵ population, per year, limits the ease of accrual of representative series of patients for robust clinical trials that could sustain informed evidence-based therapeutic decisions to optimize the quality of patient care.

Ocular adnexal non-Hodgkin's lymphoma: a review of epidemiology and risk factors

Ocular adnexal non-Hodgkin's lymphoma (NHL), the most common form of ophthalmic NHL, has a unique incidence pattern showing a steady and rapid increase in the past few decades, nearly equal rates among both genders, and predominance among Asians/Pacific Islanders. No major cause for ocular adnexal NHL has been identified, although infectious agents, immune disorders and genetic/epigenetic factors have all been implicated in its etiology. Identifying putative risk factors and biologic mechanisms leading to carcinogenesis in ocular adnexal NHL may enable implementation of effective preventive and/or therapeutic approaches for this malignancy. This article summarizes current knowledge on epidemiology of ocular adnexal NHL and the role of various potential risk factors in its etiology.

Renal small B-cell lymphoma with plasmacytic differentiation presenting with monoclonal gammopathy and disseminated intravascular coagulation syndrome

Primary renal lymphomas are very rare. However, the kidney may be a site of metastasis, usually from a disseminated aggressive lymphoma. A 58-year-old woman was brought to the medical facility due to acute mental confusion, severe hypotension, septic shock, and signs of disseminated intravascular coagulation. Laboratory tests showed severe leukopenia, renal failure, altered liver function, and elevated serum lactate dehydrogenase levels. Protein electrophoresis revealed hypergammaglobulinemia with a monoclonal peak of IgG lambda. The clinical outcome was fulminant and the patient died less than 24 hours after admission. Autopsy revealed an indolent B-cell lymphoma with extensive plasmacytic differentiation infiltrating the right renal sinus and involving the submandibular and sublingual glands, cervical and peri-aortic lymph nodes, multiple microscopic foci in pituitary and adrenal glands, lung, breast, liver, thyroid, and bone marrow. Numerous IgG4-positive plasma cells were detected by immunohistochemistry although other histological features of IgG4-related disease were missing. There was also extensive hemorrhagic necrosis of the adrenal glands and purulent cystitis, which was probably responsible for the septic shock. The authors concluded that the kidney was most likely the primary site of the indolent lymphoma, as that was the site with the largest tumor mass. Infiltration of other organs was considered as dissemination of the disease. The differential diagnosis with mucosa-associated lymphoid tissue and lymphoplasmacytic lymphoma is discussed.

Stage IV intramucosal gastric marginal zone B cell lymphoma of mucosa-associated lymphoid tissue type

A 45-year-old woman with no symptoms underwent upper gastrointestinal endoscopy. A discolored area was noted at the greater curvature of the gastric upper body. Endoscopic ultrasonography demonstrated thickening of the second sonographic layer indicating that the depth of invasion was confined to the mucosa. A urea breath test and anti-Helicobacter pylori antibody test were negative. A computed tomography scan showed a consolidation at the right lung. Gastric biopsy and transbronchial lung biopsy (TBLB) demonstrated a monotonous proliferation of atypical small lymphocytes. A diagnosis of gastric marginal zone B cell lymphoma of mucosa-associated lymphoid tissue type (MALT lymphoma) was made. The clinical stage was stage IV. A genetic analysis showed rearrangement of the joining region of the immunoglobulin heavy chain gene and identical clones in both lesions. An API2-MALT1 fusion gene was detected in the gastric lesion. After H. pylori eradication treatment, combination treatment with rituximab plus CHOP (R-CHOP) was performed; 6 months later an endoscopy revealed complete disappearance of the lesion. Multiple gastric biopsies showed no infiltrating atypical lymphocytes. Similarly, the lesion in the lung showed complete remission (CR) on CT and TBLB. This report shows that a gastric MALT lymphoma located in the mucosa and disseminated to the lung maintained CR by R-CHOP.

Multiple mucosa-associated lymphoid tissue organs involving marginal zone B cell lymphoma: organ-specific relationships and the prognostic factors. Consortium for improving survival of lymphoma study

According to a previous review, multiple mucosa-associated lymphoid tissue (MALT)-organs involving marginal zone B cell lymphomas (MZLs) are present in 10-30% of patients. However, the clinical features and specific relationships among involved organs are yet to be clearly identified. In this study, we conducted retrospective analyses of multiple MALT organs involving MZLs (MM-MZLs) to identify their clinical features, treatment, prognosis, and specific relationships among involved organs. For analysis, between June 1987 and June 2009, a total of 55 patients from 17 different institutions in Korea, all of whom were histologically diagnosed with MM-MZL, were included in this study. MM-MZL was defined as MZL involving more than 2 different MALT organs. Multiple involvements within one MALT organ (e.g. both side ocular lesions, multiple lung nodules, and multiple stomach lesions, etc.) were excluded from this study. The male/female ratio of the 55 patients was 41/14. The median age of our subjects was 59 years (range 30-82 years). MM-MZL without lymph node (LN) was detected only in 9 patients (36.2%). Bone marrow (BM) involvement was observed in 17 patients (30.9%). The most common site of involvement was the gastrointestinal (GI) tract (25 patients, 45.5%) followed by the lung (40%), Waldeyer's ring (WR) (27.3%), and ocular area (25.5%). Ocular MZLs were commonly accompanied with WR- or lung-MZLs. GI-MZLs were WR or GI-MZLs. Lung-MZLs were frequently observed with ocular and GI-MZLs. WR-MZLs were ocular or GI-MZLs. A total of 53 patients were treated, and 2 on watchful wait. As much as 48 patients received chemotherapy-based treatment. Among them, CR or PR was achieved in 38 patients (79.2%, 95% CI 67-91%). Median time to progression (TTP) was 2.3 years (95% CI 1.4-3.2 years). Cause-specific overall survival (OS) did not reach the median value. The 5-year OS rate was 84.9%. MM-MZLs tend to be an indolent disease, characterized by prolonged survival with frequent relapses. The majority of cases could be controlled effectively via chemotherapy-based treatment, and prolonged survival was achieved in those patients. The GI, lung, WR, and ocular area were commonly presented with other MALT site MZLs, and an organ-specific relationship appears to be relevant to MM-MZLs.