Recognizing nodal marginal zone lymphoma: recent advances and pitfalls. A systematic review

MNDA expression and its value in differential diagnosis of B-cell non-Hodgkin lymphomas: a comprehensive analysis of a large series of 1293 cases

AIMS

MNDA (myeloid nuclear differentiation antigen) has been considered as a potential diagnostic marker for marginal zone lymphoma (MZL), but its utility in distinguishing MZL from other B-cell non-Hodgkin lymphomas (B-NHLs) and its clinicopathologic relevance in diffuse large B-cell lymphoma (DLBCL) are ambiguous. We comprehensively investigated MNDA expression in a large series of B-NHLs and evaluated its diagnostic value.

METHODS

MNDA expression in a cohort of 1293 cases of B-NHLs and 338  cases of reactive lymphoid hyperplasia (RLH) was determined using immunohistochemistry and compared among different types of B-NHL. The clinicopathologic relevance of MNDA in DLBCL was investigated.

RESULTS

MNDA was highly expressed in MZLs (437/663, 65.9%), compared with the confined staining in marginal zone B-cells in RLH; whereas neoplastic cells with plasmacytic differentiation lost MNDA expression. MNDA expression was significantly higher in mantle cell lymphoma (MCL, 79.6%, p = 0.006), whereas lower in chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL, 44.8%, p = 0.001) and lymphoplasmacytic lymphoma (LPL, 25%, p = 0.016), and dramatically lower in follicular lymphoma (FL, 5.2%, p < 0.001), compared with MZL. 29.6% (63/213) of DLBCLs were positive for MNDA. The cases in non-GCB group exhibited a higher rate of MNDA positivity (39.8%) compared to those in GCB group (16.3%) (p < 0.001), and MNDA staining was more frequently observed in DLBCLs with BCL2/MYC double-expression (50%) than those without BCL2/MYC double-expression (24.8%) (p = 0.001). Furthermore, there was a significant correlation between MNDA and CD5 expression in DLBCL (p = 0.036).

CONCLUSIONS

MNDA was highly expressed in MZL with a potential utility in differential diagnosis between MZL and RLH as well as FL, whereas its value in distinguishing MZL from MCL, CLL/SLL is limited. In addition, MNDA expression in DLBCL was more frequently seen in the non-GCB group and the BCL2/MYC double-expression group, and demonstrated a correlation with CD5, which deserves further investigation. The clinical relevance of MNDA and its correlation with the prognosis of these lymphomas also warrant to be fully elucidated.

[CD23 positive, BCL2 rearrangement-negative germinal centre lymphomas]

Acknowledgeing that the group of follicular lymphomas is to be regarded as very heterogeneous, a group of follicular lymphomas has been delineated in recent years that was characterised by an often diffuse growth (without formation of evident follicular structures) as well as expression of CD23 in the lymphoma cells and the absence of the classic BCL2 translocation. Further characteristics are a preferred inguinal localisation of the lymphomas and a localised stage with a good prognosis. Genetically, this lymphoma group is characterised by a high rate of either STAT6 or SOCS1 mutations.The ICC classification took this development into account by introducing the provisional entity CD23 positive, BCL2 rearrangement-negative germinal centre lymphoma. Further studies must now show how exactly this entity can be defined (combination of morphology, immunohistochemical phenotype, focus on genetic alterations) in order to pave the way towards a uniform classification and a better clinical characterisation of these cases - especially with regard to possible new therapeutic treatment options.

Marginal zone lymphoma: 2023 update on diagnosis and management

DISEASE OVERVIEW

Marginal zone lymphomas (MZL) are collectively the second most common type of indolent lymphoma.

DIAGNOSIS

Three subtypes of MZL are recognized: splenic, extranodal, and nodal. The diagnosis is secured following biopsy of an involved nodal or extranodal site demonstrating a clonal B-cell infiltrate with CD5 and CD10 negative immunophenotype most common. Some cases will features IgM paraprotein, but MYD88 L256P mutations are less frequent than in Waldenstrom macroglobulinemia. Prognostication Several prognostic models have been developed, including the MALT-IPI and the MZL-IPI. The latter is broadly applicable across MZL subtypes and incorporates elevated serum LDH, anemia, lymphopenia, thrombocytopenia and nodal or disseminated subtypes as independent predictors of outcome.

TREATMENT

We discuss suggested approach to therapy for both early and advanced-stage disease, with reference to chemo-immunotherapy, radiotherapy, and emerging treatments in relapsed/refractory disease such as BTK inhibitors.

Sclerotic marginal zone lymphoma: A case report

BACKGROUND

Marginal zone lymphoma (MZL) is an indolent non-Hodgkin B cell lymphoma with various architectural pattern including perifollicular, follicular colonization, nodular, micronodular, and diffuse patterns. A sclerotic variant has not been previously reported and represents a diagnostic pitfall.

CASE SUMMARY

A 66-year-old male developed left upper extremity swelling. Chest computed tomography (CT) in September 2020 showed 14 cm mass in left axilla. Needle core biopsy of axillary lymph node showed sclerotic tissue with atypical B lymphoid infiltrate but was non-diagnostic. Excisional biopsy was performed for diagnosis and showed extensive fibrosis and minor component of infiltrating B cells. Flow cytometry showed a small population of CD5-, CD10-, kappa restricted B cells. Monoclonal immunoglobulin heavy chain and light chain gene rearrangement were identified. Upon being diagnosed with MZL, patient was treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone and achieved complete remission by positron emission tomography/CT.

CONCLUSION

This is an important case report because by morphology this case could have easily been overlooked as non-specific fibrosis with chronic inflammation representing a significant diagnostic pitfall. Moreover, this constitutes a new architectural pattern. While sclerotic lymphomas have rarely been described (often misdiagnosed as retroperitoneal fibrosis), we do not know of any cases describing this architectural presentation of MZL.

De-Novo B-Cell Prolymphocytic Leukemia

B-cell prolymphocytic leukemia (B-PLL) is a rare B-cell neoplasm that typically presents with splenomegaly, a rising white blood cell count, and may or may not have B symptoms. The diagnosis usually requires a bone marrow biopsy and aspirate with flow cytometry and cytogenetic studies. At least 55% of the lymphocytes in the peripheral blood must be prolymphocytes to be defined as B-PLL. A thorough differential diagnosis would include mantle cell lymphoma, chronic lymphocytic leukemia (CLL) with prolymphocytes, hairy cell leukemia, and splenic marginal zone lymphoma. B-PLL is managed with regimens utilized for CLL, such as ibrutinib and rituximab but is tailored for each individual. The authors report a rare case of B-PLL in a patient with no known history of CLL. The authors discuss this entity in context of the 2017 and 2022 World Health Organization (WHO) classifications, the latter of which no longer recognizes B-PLL as a distinct entity. The authors hope that this article helps practitioners with the diagnosis and treatment of B-PLL. Perhaps with better recognition, and better documentation of histopathologic features of these rare cases going forward, it may prove to be a distinct entity again in future classifications.

Management of Marginal Zone Lymphoma: A Canadian Perspective

Marginal zone lymphomas (MZL) are a rare, heterogenous group of lymphomas, accounting for 5-17% of indolent non-Hodgkin lymphomas in the western world. They can be further divided into three subtypes: extranodal MZL, splenic MZL, and nodal MZL. These subtypes differ in clinical presentation and behavior, which influences how they are managed. There is currently no standard of care for the treatment of MZL, owing to the difficulty in conducting phase 3 randomized trials in MZL, and the fact that there are limited data on the efficacy of therapy in individual subtypes. Treatment practices are thus largely borrowed from other indolent lymphomas and are based on patient and disease characteristics, as well as access to therapy. This review summarizes the Canadian treatment landscape for MZL and how these therapies may be sequenced in practice.

The 5th edition of the World Health Organization Classification of Haematolymphoid Tumours: Lymphoid Neoplasms

We herein present an overview of the upcoming 5^th edition of the World Health Organization Classification of Haematolymphoid Tumours focussing on lymphoid neoplasms. Myeloid and histiocytic neoplasms will be presented in a separate accompanying article. Besides listing the entities of the classification, we highlight and explain changes from the revised 4^th edition. These include reorganization of entities by a hierarchical system as is adopted throughout the 5^th edition of the WHO classification of tumours of all organ systems, modification of nomenclature for some entities, revision of diagnostic criteria or subtypes, deletion of certain entities, and introduction of new entities, as well as inclusion of tumour-like lesions, mesenchymal lesions specific to lymph node and spleen, and germline predisposition syndromes associated with the lymphoid neoplasms.

Management of Extranodal Marginal Zone Lymphoma: Present and Upcoming Perspectives

Simple Summary

Extranodal marginal zone lymphoma distinguishes itself from other indolent lymphomas due to its unique pathophysiology and natural history. This is reflected in its management, where next to traditional treatment strategies such as observation, radiotherapy or chemotherapy, eradication of the causal agent and even surgery represent important aspects of therapy. This review focuses on the particular aspects of this indolent lymphoma that affect management and summarizes the current evidence and different guidelines.

Abstract

Extranodal marginal zone lymphoma (EMZL) encompasses a subgroup of non-Hodgkin lymphomas that often present with localized involvement and may manifest in a diversity of organs and tissues. EMZL pathogenesis is in some cases linked to chronic inflammation/infection, which may impose additional diagnostic and clinical challenges. The most studied and established connection is the presence of Helicobacter pylori in gastric EMZL. Due to its heterogeneity of presentation and intricate pathological features, treatment can be complex, and staging systems are decisive for the choice of therapy. Nevertheless, there is no consensus regarding the most suitable staging system, and recommendations vary among different countries. As a rule of thumb, in limited stages, a local therapy with surgery or radiation is the preferred option, and it is potentially curative. Of note, eradicating the causal agent may be an important step of treatment, especially in gastric EMZL, in which Helicobacter pylori eradication remains the first-line therapy for the majority of patients. In patients with more advanced stages, watch-and-wait is a valuable option, especially amongst those without clear indications for systemic therapy, and it may be carried on for several years. If watch-and-wait is not an option, systemic therapy may be needed. Even though several agents have been tested as monotherapy or in combination in recent years, there is no consensus regarding the first-line therapy, and decisions can vary depending on individual factors, such as age, clinical performance and stage. This review aims to discuss the several aspects of EMZL, including genetic milieu, pathogenesis and staging systems, that may influence the choice of therapy. In addition, we present a summary of evidence of several systemic therapies, compare different recommendations worldwide and discuss future perspectives and novelties in its therapy.

Follicular lymphoma presenting like marginal zone lymphoma: A case report

BACKGROUND

Follicular lymphoma (FL), a common type of indolent lymphoma, carries markers of the germinal center, and the rearrangement of the BCL-2 gene is regarded as an initiating event and a hallmark of the neoplasm. When FL has marginal zone differentiation, some marginal zone features are carried by the neoplasm.

CASE SUMMARY

A 54-year-old male with lymphadenopathy, splenomegaly and hyperlymphocytosis was diagnosed with FL with marginal zone differentiation. The tumor demonstrated different features in the bone marrow (BM) compared with the follicle of the lymph node (LN). Some component of the neoplasm mimicked marginal zone lymphoma, such as infiltrating the marginal zone of the LN, displaying a monocytoid shape and lacking the expression of CD10 in the BM. The diagnosis of FL was made due to the concurrent detection of BCL-2 rearrangement in the LN and BM.

CONCLUSION

Discordant pathological features in LN and BM could mislead diagnosis. When clinical and pathological manifestations are confusing in diagnosis, typical genetic abnormalities are decisive.

The Relevance of Additional Immunohistochemical Markers on the Differential Diagnosis of Small B-Cell Lymphomas: A Case-control Study

Objective:

Clinical and pathological differential diagnosis of small B-cell lymphomas (SBCLs) is still controversial and may be difficult due to their overlapping morphology, phenotype, and differentiation to plasma cells. We aimed to examine the expression of the immune receptor translocation-associated protein 1 (IRTA1), myeloid cell nuclear differentiation antigen (MNDA), lymphoid enhancer-binding factor-1 (LEF1), and stathmin 1 (STMN1) markers in SBCL cases involving different sites that may have plasma cell differentiation.

Materials and Methods:

We studied 154 tissue samples with lymphoma involvement from 116 patients and evaluated the staining distribution of the markers. Expressions were evaluated in 21 chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), 7 follicular lymphoma (FL), 14 nodal marginal zone lymphoma, 17 extranodal marginal zone lymphoma, 55 splenic marginal zone lymphoma, 22 marginal zone lymphoma-not otherwise specified, and 18 lymphoplasmacytic lymphoma/Waldenström macroglobulinemia cases by immunohistochemistry.

Results:

The results confirmed that LEF1 was the most sensitive and specific marker for CLL/SLL and STMN1 was the most sensitive and specific marker for FL (p<0.001). MNDA and IRTA1 were useful markers to distinguish marginal zone lymphomas.

Conclusion:

Our results suggest that LEF1 for CLL/SLL and STMN1 for FL are reliable markers. LEF1, MNDA, STMN1, and IRTA1 are helpful with other routinely used immunohistochemical markers in a diagnostic algorithm considering their limitations.

DNA Methylation-Based Classification of Small B-Cell Lymphomas: A Proof-of-Principle Study

Although most small B-cell lymphomas (SBCLs) can be diagnosed using routine methods, challenges exist. For example, marginal zone lymphomas (MZLs) can be difficult to rule-in, in large part because no widely-used, sensitive, and specific biomarker is available for the marginal zone cell of origin. In this study, it was hypothesized that DNA methylation array profiling can assist with the classification of SBCLs, including MZLs. Extramedullary SBCLs, including challenging cases, were reviewed internally for pathology consensus and profiled. By combining the resulting array data set with data sets from other groups, a set of 26 informative probes was selected and used to train machine learning models to classify 4 common SBCLs: chronic lymphocytic leukemia/small lymphocytic lymphoma, follicular lymphoma, mantle cell lymphoma, and MZL. Prediction probability cutoff was used to separate classifiable from unclassifiable cases, and show that the trained model was able to classify 95% of independent test cases (n = 264/279). The concordance between model predictions and pathology diagnoses was 99.6% (n = 262/263) among classifiable test cases. One validation reference test case was reclassified based on model prediction. The model was also used to predict the diagnoses of two challenging SBCLs. Although the differential examined and data on difficult cases are limited, these results support accurate methylation-based classification of SBCLs. Furthermore, high specificities of predictions suggest that methylation signatures can be used to rule-in MZLs.

Mutational landscape of marginal zone B-cell lymphomas of various origin: organotypic alterations and diagnostic potential for assignment of organ origin

This meta-analysis aims to concisely summarize the genetic landscape of splenic, nodal and extranodal marginal zone lymphomas (MZL) in the dura mater, salivary glands, thyroid, ocular adnexa, lung, stomach and skin with respect to somatic variants. A systematic PubMed search for sequencing studies of MZL was executed. All somatic mutations of the organs mentioned above were combined, uniformly annotated, and a dataset containing 25 publications comprising 6016 variants from 1663 patients was created. In splenic MZL, KLF2 (18%, 103/567) and NOTCH2 (16%, 118/725) were the most frequently mutated genes. Pulmonary and nodal MZL displayed recurrent mutations in chromatin-modifier-encoding genes, especially KMT2D (25%, 13/51, and 20%, 20/98, respectively). In contrast, ocular adnexal, gastric, and dura mater MZL had mutations in genes encoding for NF-κB pathway compounds, in particular TNFAIP3, with 39% (113/293), 15% (8/55), and 45% (5/11), respectively. Cutaneous MZL frequently had FAS mutations (63%, 24/38), while MZL of the thyroid had a higher prevalence for TET2 variants (61%, 11/18). Finally, TBL1XR1 (24%, 14/58) was the most commonly mutated gene in MZL of the salivary glands. Mutations of distinct genes show origin-preferential distribution among nodal and splenic MZL as well as extranodal MZL at/from different anatomic locations. Recognition of such mutational distribution patterns may help assigning MZL origin in difficult cases and possibly pave the way for novel more tailored treatment concepts.

Prospective Phase II trial of radiation therapy in localised non-gastric marginal zone lymphoma with prospective evaluation of autoimmunity and Helicobacter pylori status: TROG 05.02/ALLG NHL15

BACKGROUND

This Phase 2 multicentre trial in localised non-gastric marginal zone lymphoma (MZL) evaluated the effectiveness and safety of radiotherapy and documented markers of autoimmunity and Helicobacter pylori infection.

PATIENTS AND METHODS

Eligible patients had Stages I and II or paired-organ, non-gastric MZL. Bone marrow evaluation, autoantibody panel, and H. pylori evaluation were mandatory. Involved-field or involved-site radiotherapy was delivered to 24-30.6 Gy. Detected H. pylori infections underwent eradication.

RESULTS

Between 2006 and 2014, six centres enrolled 70 patients, and 68 commenced treatment. The median age was 59 (range: 23-84) years, and 31 (46%) were male. Overall, 55 patients had Stage I disease, nine patients had Stage II disease, and four patients had paired organ-confined disease. Involved extranodal sites with three or more cases were orbital (n = 18), conjunctiva (n = 13), lacrimal (n = 8), skin (n = 8), salivary (n = 7), and muscle (n = 4). Eight patients had primary nodal MZL. At the median follow-up of 5 years (range 0.7-9.4), progression-free survival and overall survival were 79% and 95%, respectively. One lymphoma-related death and two in-field failures (after 25 and 30 Gy, respectively) occurred. Distant relapse sites were skin (n = 2), lymph nodes (n = 2), duodenum, stomach, muscle, and conjunctiva (1 each). No paired-organ MZL relapsed. Apart from cataracts (n = 18), only three treatment-related late grade ≥3 adverse events occurred. Autoantibodies or autoimmune events were detected in 26 of 68 patients (38%). H. pylori infection was detected in 15 of 63 patients (24%) tested. Neither autoimmunity nor H. pylori was detected in 27 of 68 patients (40%).

CONCLUSIONS

Radiotherapy was a potentially curative treatment with low toxicity in localised non-gastric MZL. Autoimmunity, H. pylori infection or both were detected in 60% of patients.

Follicular lymphoma t(14;18)-negative is genetically a heterogeneous disease

Fifty-five cases of t(14;18)- follicular lymphoma (FL) were genetically characterized by targeted sequencing and copy number (CN) arrays. t(14;18)- FL predominated in women (M/F 1:2); patients often presented during early clinical stages (71%), and had excellent prognoses. Overall, t(14;18)- FL displayed CN alterations (CNAs) and gene mutations carried by conventional t(14;18)+ FL (cFL), but with different frequencies. The most frequently mutated gene was STAT6 (57%) followed by CREBBP (49%), TNFRSF14 (39%), and KMT2D (27%). t(14;18)- FL showed significantly more STAT6 mutations and lacked MYD88, NOTCH2, MEF2B, and MAP2K1 mutations compared with cFL, nodal marginal zone lymphoma (NMZL), and pediatric-type FL (PTFL). We identified 2 molecular clusters. Cluster A was characterized by TNFRSF14 mutations/1p36 alterations (96%) and frequent mutations in epigenetic regulators, with recurrent loss of 6q21-24 sharing many features with cFL. Cluster B showed few genetic alterations; however, a subgroup with STAT6 mutations concurrent with CREBBP mutations/16p alterations without TNFRSF14 and EZH2 mutations was noted (65%). These 2 molecular clusters did not distinguish cases by inguinal localization, growth pattern, or presence of STAT6 mutations. BCL6 rearrangements were demonstrated in 10 of 45 (22%) cases and did not cluster together. Cases with predominantly inguinal presentation (20 of 50; 40%) had a higher frequency of diffuse growth pattern, STAT6 mutations, CD23 expression, and a lower number of CNAs, in comparison with noninguinal cases (5.1 vs 9.1 alterations per case; P < .05). STAT6 mutations showed a positive correlation with CD23 expression (P < .001). In summary, t(14;18)- FL is genetically a heterogeneous disorder with features that differ from cFL, NMZL, and PTFL.

The Multifaceted Role and Utility of MicroRNAs in Indolent B-Cell Non-Hodgkin Lymphomas

Normal B-cell development is a tightly regulated complex procedure, the deregulation of which can lead to lymphomagenesis. One common group of blood cancers is the B-cell non-Hodgkin lymphomas (NHLs), which can be categorized according to the proliferation and spread rate of cancer cells into indolent and aggressive ones. The most frequent indolent B-cell NHLs are follicular lymphoma and marginal zone lymphoma. MicroRNAs (miRNAs) are small non-coding RNAs that can greatly influence protein expression. Based on the multiple interactions among miRNAs and their targets, complex networks of gene expression regulation emerge, which normally are essential for proper B-cell development. Multiple miRNAs have been associated with B-cell lymphomas, as the deregulation of these complex networks can lead to such pathological states. The aim of the present review is to summarize the existing information regarding the multifaceted role of miRNAs in indolent B-cell NHLs, affecting the main B-cell subpopulations. We attempt to provide insight into their biological function, the complex miRNA-mRNA interactions, and their biomarker utility in these malignancies. Lastly, we address the limitations that hinder the investigation of the role of miRNAs in these lymphomas and discuss ways that these problems could be overcome in the future.

Flow cytometry in the diagnosis of mature B-cell lymphoproliferative disorders

B-lineage lymphoproliferative disorders (LPD) are rather frequent diseases, associated with specific clinical or biological features but also sometimes of fortuitous discovery. Multiparameter flow cytometry plays a major role for a rapid diagnostic indication, on peripheral blood or bone marrow samples in most instances, guiding complementary analyses and allowing for the proper therapeutic management of patients. After describing the important pre-analytical precautions required for an adequate assessment, the immunophenotypic features of small-cell and large-cell lymphomas are described in this review. The ubiquitous expression of CD19 is a first mandatory gating step. A possible clonal proliferation is then suspected by the demonstration of surface immunoglobulin light chain restriction. The aberrant presence of CD5 allows to segregate chronic lymphocytic leukemia and mantle cell lymphoma in most cases. Other LPD exhibit specific immunophenotypic features. A table of useful markers and a decision tree are provided. Of note, immunophenotypic data should as much as possible be interpreted in an integrated manner, involving the patient's clinical and other biological features, and be completed by further chromosomal and/or molecular investigations.

Treatment outcomes of IgG4-producing marginal zone B-cell lymphoma: a retrospective case series

IgG4-producing marginal zone B-cell lymphomas (MZLs) have been recently proposed as a subtype of MZLs. Despite the abundant literature on pathophysiological features of this type of lymphoma, only a few retrospective studies pertaining to the treatment outcomes have been reported, and its prognosis remains unclear. We retrospectively analyzed seven patients with IgG4-producing MZLs diagnosed at our institute, with specific reference to treatment and outcomes. The median age was 69.0 years (55-79), and all were males. The median follow-up period was 66.6 months (8-121). All patients had localized disease; four patients had tumors of the ocular adnexa, whereas two had retroperitoneal tumors. Five patients were treated with irradiation (30 Gy/15 fr) (n = 4) or surgery (n = 1), resulting in tumor reduction. Two patients were treated by chemotherapy or irradiation. Among them, one commenced rituximab monotherapy, which led to an inadequate reduction of the tumor. Subsequent irradiation induced complete response (CR). The other patient experienced repeated relapses during follow-up and finally achieved CR by combination chemotherapy. Treatment was well tolerated in all cases, and none of the patients showed disease progression at the last follow-up visit. Our results indicate that the standard treatments for MZLs are generally appropriate for IgG4-producing MZL.

Expansion of PD1-positive T Cells in Nodal Marginal Zone Lymphoma: A Potential Diagnostic Pitfall

The diagnosis of nodal marginal zone lymphoma (NMZL) can be challenging, with the differential diagnosis including other low-grade B-cell lymphomas, reactive hyperplasia, and even some cases of peripheral T-cell lymphoma (PTCL). PTCL may have a perifollicular growth pattern mimicking NMZL. We and others have noted an atypical distribution of T-follicular helper (TFH) cells in some cases of NMZL. This study was prompted by the diagnosis of NMZL in several cases in which a marked increase of TFH cells, as determined by staining for programmed death-1 (PD1), had prompted suspicion for a diagnosis of PTCL. We analyzed PD1 staining in 48 cases of NMZL to characterize the extent and pattern of the PD1-positive infiltrate. Three main patterns of PD1 staining were identified: follicular pattern (peripheral, n=16; central, n=9; mixed, n=3), diffuse pattern (n=4), and a reduced or normal staining pattern in residual follicles (n=16). A comprehensive analysis of other TFH markers was undertaken in 14 cases with a high content of PD1-positive cells that were confirmed as B-cell lymphoma by clonality analysis. We describe in detail 5 of these cases in which PTCL was an initial consideration. This study illuminates the diverse immunohistochemical patterns encountered in NMZL and highlights a diagnostic pitfall important for diagnostic accuracy.

Long-Term Observation of the Progression From Nodal Marginal Zone Lymphoma to Diffuse Large B-Cell Lymphoma in a Dog

A 4-year and 10-month old female Pembroke Welsh Corgi presented with an enlarged right popliteal lymph node, and a histopathological diagnosis of nodal marginal zone lymphoma (nMZL) was made. After resection of the lymph node, follow-up observation was continued without chemotherapy. At 22 months after initial presentation, the dog developed enlargement of peripheral lymph nodes, and the histopathological diagnosis was late-stage nMZL. Multidrug chemotherapy induced clinical complete remission, but the tumor relapsed with enlargement of peripheral and abdominal lymph nodes 42 months after initial presentation. Second-round multidrug chemotherapy induced complete clinical remission again; however, the tumor relapsed with lymphadenopathy 47 months after initial presentation. The dog died 59 months after initial presentation, and postmortem examination revealed generalized lymphadenopathy; the histopathological diagnosis was diffuse large B-cell lymphoma (DLBCL). Polymerase chain reaction for antigen receptor gene rearrangements revealed that the nMZL and DLBCL samples were derived from the same B-lymphocyte clone.

[The prognostic significance of POD24 in 106 cases with splenic marginal lymphoma with bone marrow invasion]

目的

探讨24个月内疾病进展（POD24）对伴骨髓侵犯的脾边缘区淋巴瘤（SMZL）患者总生存的影响，比较POD24与非POD24患者的临床特征。

方法

回顾性分析2002年1月至2017年1月中国医学科学院血液病医院收治的有治疗指征且经过正规治疗的伴骨髓侵犯的SMZL患者，选取随访时间足以对POD24进行判断的患者（排除因非进展因素发生死亡的患者），进行预后评估及临床特征比较。

结果

共入组患者106例，中位年龄57（25～79）岁。①临床特征：全部患者均有骨髓侵犯和脾肿大，其中巨脾59.4％（63/106），肝大14.8％（15/101）；复杂核型22.7％（18/79），13q缺失5.1％（4/78），11q缺失1.3％（1/72），17p缺失2.5％（2/80），12号染色体三体（CEP12）7.5％（4/53）。②生存分析：单因素分析提示POD24、HGB<100 g/L以及CEP12为与总生存相关的不良预后因素；多因素分析提示仅POD24有独立预后意义［HR＝20.116（95％CI 2.226～181.820），P＝0.008］。③亚组分析：POD24患者较非POD24患者起病时纵隔淋巴结肿大的发生率（63.6％对18.9％，P＝0.005）及复杂核型发生率（50.0％对17.9％，P＝0.024）明显增高；腹腔淋巴结肿大、贫血、血小板减少、白蛋白下降以及乳酸脱氢酶增高的发生率在POD24患者中更高，与非POD24患者相比差异无统计学意义（P>0.05）。

结论

POD24为影响伴骨髓侵犯的SMZL患者总生存的独立预后不良因素，起病时伴纵隔淋巴结肿大及复杂核型的患者发生POD24比例更高。

Significance of CD10 protein expression in the diagnostics of follicular lymphoma: A comparison of conventional immunohistochemistry with flow cytometry supported by the establishment of BCL2 and BCL6 rearrangements

INTRODUCTION

Histopathological examination and immunohistochemistry (IHC) with a crucial role of CD10 expression remain a standard diagnostic tool in follicular lymphoma (FL). The results of IHC CD10 detection with different primary antibodies are not fully reproducible, but some reports show that flow cytometry (FCM) can be a reliable method of CD10 identification.

METHODS

The aim of the study was to compare results of CD10 expression in FL by IHC and FCM including immunophenotypic features in the context of the BCL2 and BCL6 alterations.

RESULTS

Out of 76 histopathologically diagnosed FL, a group of 25 cases had simultaneously FCM. Immunohistochemically 77.6% of cases were CD10-positive with comparable and reproducible results to FCM. Differences between the FCM expression of CD5/CD10/CD11c/CD25/CD43 and BCL2 overexpression (BCL2(+)^higher ) correlated with the BCL2 and BCL6 rearrangements (R) status. Lack of CD10 expression corresponded with the absence of BCL2R and higher MUM1 expression by IHC results but had no clinical impact on the long-time outcomes.

CONCLUSIONS

Immunohistochemistry staining is a comparable method to FCM assessment in the evaluation of CD10 expression and diagnosis of FL. Fine-needle aspiration biopsy/FCM (FNAB/FCM) could be a useful tool for verifying FL diagnosis and CD10 detection. Despite its heterogeneity, FL has a characteristic immunophenotype. BCL2R and BCL6R FL cases differ mainly in levels of BCL2 and CD10 with CD43 co-expression; BCL2(+)^higher by FCM correlates with BCL2R. Moreover, FNAB plays an important role in material provision for supportive karyotyping and BCL2R, BCL6R assessed by FISH.

Front-line management of indolent non-Hodgkin lymphoma in Australia. Part 2: mantle cell lymphoma and marginal zone lymphoma

Mantle cell lymphoma (MCL) and the marginal zone lymphoma (MZL) subtypes (nodal MZL, extra-nodal MZL of mucosa-associated lymphoid tissue (MALT lymphoma) and splenic MZL) are uncommon lymphoma subtypes, accounting for less than 5-10% of all non-Hodgkin lymphoma. The evidence base for therapy is therefore limited and enrolment into clinical trials is preferred. Outcomes for patients with MCL have been steadily improving mainly due to the adoption of more intense strategies in younger patients, the use of rituximab maintenance and the recent introduction of bendamustine in older patients. MZL is a more heterogeneous group of cancer with both nodal, extra-nodal and splenic subtypes. Extranodal MZL may be associated with autoimmune or infectious aetiologies, and can respond to eradication of the causative pathogen. Proton pump inhibitor plus dual antibiotics in Helicobacter pylori positive gastric MALT lymphoma is curative in many patients. Watchful waiting is appropriate in most patients with asymptomatic advanced stage disease, which tends to behave in a particularly indolent manner. Other options for symptomatic disease include splenectomy, chemoimmunotherapy with rituximab and, more recently, targeted therapies.

Risk of second primary papillary thyroid cancer among adult cancer survivors in the United States, 2000-2015

BACKGROUND

While radiotherapy is a major risk factor for thyroid cancer after childhood cancer, factors contributing to increased thyroid cancer risk after adulthood cancer remain unclear.

METHODS

We evaluated second primary papillary thyroid cancer (PTC) risk among 3,175,216 ≥ 1-year adult survivors of non-thyroid malignancies from US population-based cancer registries (2000-2015), using standardized incidence ratios (SIRs). Because heightened surveillance may increase detection of indolent thyroid tumors and earlier detection of advanced tumors, we examined SIRs by PTC stage and time since first cancer (latency).

RESULTS

SIRs for second primary PTC (N = 4333) were statistically-significantly 1.2-3.5-fold elevated overall and after 23/27 first cancer types evaluated, with generally similar risks for localized and regional/distant PTC. SIRs for regional/distant PTC (N = 1501) were highest after pancreatic (SIR = 3.7; 95% confidence interval [CI] = 1.9-6.5) and soft tissue (SIR = 4.2; 95%CI = 2.8-6.2) cancers, followed by melanoma, chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), diffuse large B-cell lymphoma, and larynx, kidney, and brain/central nervous system (SIRs = 2.0-2.9) cancers. SIRs typically decreased with increasing latency but remained statistically-significantly elevated for regional/distant-PTC ≥5 years after diagnosis of cancers of the rectum, pancreas, lung/bronchus, soft tissue, female breast, uterine corpus, prostate, and kidney, and after melanoma, Hodgkin lymphoma, CLL/SLL, and follicular lymphoma. Neither total nor regional/distant PTC were clearly associated with initial course of radiotherapy or chemotherapy.

CONCLUSIONS

PTC risk was elevated after a range of first primary adult cancers but was not clearly related to treatment. Although surveillance may contribute to elevated short-term risks of PTC, longer-term elevations in regional/distant PTC may be attributable to shared risk factors.

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.

Unclassifiable Isolated Monoclonal Lymphocytosis: Comprehensive Description of a Retrospective Cohort

According to the World Health Organization (WHO) classification, the nosology of B-cell neoplasms integrates clinical, morphological, phenotypic, and genetic data. In this retrospective analysis, we identified 18 patients with isolated neoplastic lymphocytosis that could not be accurately classified within the WHO classification. Most of them were asymptomatic at the time of diagnosis and the evolution was relatively indolent, as only five patients required treatment after a median follow-up of 48 months. The neoplastic B-cells expressed CD5 in most cases, but the Royal Marsden Hospital score was strictly below 3. Trisomy 12 was the most frequent cytogenetic abnormality. High-throughput sequencing highlighted mutations found in both chronic lymphocytic leukemia (CLL) and marginal zone lymphoma (MZL). Similarly, the immunoglobulin heavy chain variable region repertoire was distinct from those reported in CLL or MZL. However, as treatment choice is dependent on the correct classification of the lymphoproliferative disorder, a histological diagnosis should be performed in case patients need to be treated.

[Histopathological classification of chronic B-lymphoproliferative disorders]

Chronic lymphoproliferative disorders should be classified according to the revised 2016 WHO classification. Biopsies are not mandatory for all chronic lymphoproliferative disorders as blood or bone marrow cytologroachical approach can be sufficient for some lymphoma entities. Diagnostic is based on a multidiscplinary approach taking into account clinical presentation, histopathological, cytological, immunophenotypical features (immunohistochemistry and Flow cytometry) and molecular pattern (translocation by FISH, Mutations landscape by NGS, and genomic abnormalities by CGH array). An important heterogeneity of clinical presentation and prognosis arises within the same lymphoma subtype. Clinical evolution is characterized by relapses, cytological progression and transformation into diffuse large B cell lymphoma, aggressive lymphoma or high-grade lymphomas.

Monocytoid B cell lymphoma: A case report and evaluation

Lymphomas are a group of malignant blood cell tumors that develop from lymphocytes. Two main categories of lymphomas are Hodgkin and non-Hodgkin lymphomas (NHL), of which 90% are of the NHL type. The objectives of classifying is to help in the identification of homogenous group of well-defined entities and facilitating the recognition of uncommon diseases that further require classification as it affects prognosis and therapeutic implications. Nodal marginal zone lymphoma, also known as monocytoid B-cell lymphoma (MBCL), is an uncommon form of lymphoma representing 1.5%-1.8% of lymphoid neoplasms, with only rare reports in the literature that have attempted morphologic or immunophenotypic characterization. Specific markers for MBCLs are still lacking, so its diagnosis is based on exclusion of other small B-cell lymphomas. This article illustrates a case report of MBCL highlighting the intricacies and difficulties involved in establishing a diagnosis.

IRTA1 and MNDA Expression in Marginal Zone Lymphoma: Utility in Differential Diagnosis and Implications for Classification

Objectives

To evaluate the clinical utility of immune receptor translocation-associated protein 1 (IRTA1) and myeloid nuclear differentiation antigen (MNDA) expression in the diagnosis and classification of marginal zone lymphomas (MZLs).

Methods

IRTA1 was examined using a novel RNA in situ hybridization assay and MNDA expression determined by immunohistochemistry in 127 small B-cell neoplasms, including 80 cases of MZL.

Results

IRTA1 expression was detected in 31 (42%) of 74 MZLs vs one (2%) of 43 other small B-cell neoplasms (P < .001). MNDA staining was positive in 51 (64%) of 79 MZLs vs 21 (45%) of 46 non-MZLs (P = .06). MNDA expression was particularly uncommon in follicular lymphoma (3/14, 21%; P = .003 vs MZL). There was no association between MNDA and IRTA1 expression and the presence of monocytoid cytology. IRTA1 expression was less frequent in cases with a diffuse growth pattern.

Conclusions

IRTA1 and MNDA are useful markers in the differential diagnosis of MZLs.

A patient with a diagnosis of nodal marginal zone B-cell lymphoma and a t(2;14)(p24;q32) involving MYCN and IGH

Background

Nodal marginal zone B-cell lymphoma is a rare entity in which the cytogenetic findings are not well defined. The t(2;14)(p24;q32) has previously been reported in three patients with blastic mantle cell lymphoma and one patient with follicular lymphoma. This rearrangement has not been reported previously in a patient with a diagnosis of nodal marginal zone B-cell lymphoma.

Case presentation

We present a male patient who presented with lymphadenopathy. On the basis of his clinicoradiologic presentation, morphological appearances, immunophenotype and molecular findings he was determined to have a diagnosis of nodal marginal zone B-cell lymphoma. Cytogenetic analysis demonstrated a t(2;14)(p24;q32). Further FISH testing showed this rearrangement to involve the MYCN and IGH genes.

Conclusions

We present the first patient with a diagnosis of nodal marginal zone B-cell lymphoma with a t(2;14)(p24;q32). This rearrangement has been described in three other patients who have had a diagnosis of lymphoma. Our findings suggest this rearrangement is not specific to mantle cell lymphoma or follicular lymphoma. The number of cases described are still too low to draw firm conclusions regarding the nature of this rearrangement. In order to refine the clinical and prognostic picture of this finding, publication of further cases is required.

The current role of clinical flow cytometry in the evaluation of mature B-cell neoplasms

Flow cytometry (FC) has a well-established role in the diagnostic evaluation of mature B-cell neoplasms. Effective assessment for lineage associated antigens, aberrant antigen expression, and immunoglobulin light chain restriction requires a well-designed, optimized, and controlled FC assay. However, it is important for hematopathologists to know when flow cytometry has a more limited role, and other modalities, such as immunohistochemistry, cytogenetic and molecular testing, are more important. This review will discuss the features of an optimal FC assay for the evaluation of mature B-cell neoplasms, and the current role of FC in the diagnosis and sub-classification, prognostic assessment, identification of therapeutic targets, and assessment for disease response to therapy. © 2018 International Clinical Cytometry Society.

Antiphospholipid antibodies associated with nodal marginal zone lymphoma and its progression to diffuse large B-cell lymphoma-A case report

An association between autoimmune events, as well as the development of antiphospholipid (aPL) antibodies and lymphoproliferative disorders is well recognized. We present the patient with coagulation abnormalities and non-Hodgkin lymphoma (NHL), primarily diagnosed as nodal marginal zone B-cell lymphoma (NMZL), and in relapse as diffuse large B-cell lymphoma (DLBCL). In the follow-up period, the patient simultaneously developed different aPL antibodies. The presence of aPL antibodies in NHL is frequent but it is not common in the NMZL. The aim of the present case report is to highlight the possible underlying increase of aPL antibodies in NMZL patients with coagulation tests abnormalities.

Diagnosis of Lymphoid Lesions in Limited Samples: A Guide for the General Surgical Pathologist, Cytopathologist, and Cytotechnologist

OBJECTIVES

Advances in interventional techniques allow obtaining samples from most body sites through minimally invasive procedures that yield limited samples. We provide practical guidelines for diagnosis of lymphoid lesions in these samples.

METHODS

Guidelines for selection of biopsy site and triage of the specimen according to results of rapid on-site evaluation (ROSE), and description of the advantages and limitations of currently available ancillary studies are described, based on the experience of the authors, complemented by a comprehensive review of the literature.

RESULTS

Five diagnostic categories are observed at ROSE: (1) preponderance of small cells, (2) large cells, (3) mixed small and large cells, (4) blast-like cells, and (5) rare large pleomorphic cells. Detailed description of the diagnostic work-up and subsequent classification for each of these groups is provided.

CONCLUSIONS

A definitive diagnosis of lymphoid neoplasms in limited samples is possible in most cases through correlation of morphology, ancillary studies, and clinical scenario.

Recent advances in understanding the biology of marginal zone lymphoma

There are three different marginal zone lymphomas (MZLs): the extranodal MZL of mucosa-associated lymphoid tissue (MALT) type (MALT lymphoma), the splenic MZL, and the nodal MZL. The three MZLs share common lesions and deregulated pathways but also present specific alterations that can be used for their differential diagnosis. Although trisomies of chromosomes 3 and 18, deletions at 6q23, deregulation of nuclear factor kappa B, and chromatin remodeling genes are frequent events in all of them, the three MZLs differ in the presence of recurrent translocations, mutations affecting the NOTCH pathway, and the transcription factor Kruppel like factor 2 ( KLF2) or the receptor-type protein tyrosine phosphatase delta ( PTPRD). Since a better understanding of the molecular events underlying each subtype may have practical relevance, this review summarizes the most recent and main advances in our understanding of the genetics and biology of MZLs.

High-throughput sequencing of nodal marginal zone lymphomas identifies recurrent BRAF mutations

Nodal marginal zone lymphoma (NMZL) is a rare small B-cell lymphoma lacking disease-defining phenotype and precise diagnostic markers. To better understand the mutational landscape of NMZL, particularly in comparison to other nodal small B-cell lymphomas, we performed whole-exome sequencing, targeted high-throughput sequencing, and array-comparative genomic hybridization on a retrospective series. Our study identified for the first time recurrent, diagnostically useful, and potentially therapeutically relevant BRAF mutations in NMZL. Sets of somatic mutations that could help to discriminate NMZL from other closely related small B-cell lymphomas were uncovered and tested on unclassifiable small B-cell lymphoma cases, in which clinical, morphological, and phenotypical features were equivocal. Application of targeted gene panel sequencing gave at many occasions valuable clues for more specific classification.

Canine nodal marginal zone lymphoma: Descriptive insight into the biological behaviour

Canine nodal marginal zone lymphoma (nMZL) is classified as an indolent lymphoma. Such lymphomas are typified by low mitotic rate and slow clinical progression. While the clinical behaviour of canine splenic MZL has been described, characterized by an indolent course and a good prognosis following splenectomy, there are no studies specifically describing nMZL. The aim of this study was to describe the clinical features of and outcome for canine nMZL. Dogs with histologically confirmed nMZL undergoing a complete staging work-up (including blood analysis, flow cytometry [FC] on lymph node [LN], peripheral blood and bone marrow, imaging, histology and immunohistochemistry on a surgically removed peripheral LN) were retrospectively enrolled. Treatment consisted of chemotherapy or chemo-immunotherapy. Endpoints were response rate (RR), time to progression (TTP) and lymphoma-specific survival (LSS). A total of 35 cases were enrolled. At diagnosis, all dogs showed generalized lymphadenopathy. One-third was systemically unwell. All dogs had stage V disease; one-third also had extranodal involvement. The LN population was mainly composed of medium-sized CD21+ cells with scant resident normal lymphocytes. Histology revealed diffuse LN involvement, referring to "late-stage" MZL. Median TTP and LSS were 149 and 259 days, respectively. Increased LDH activity and substage b were significantly associated with a shorter LSS. Dogs with nMZL may show generalized lymphadenopathy and an advanced disease stage. Overall, the outcome is poor, despite the "indolent" designation. The best treatment option still needs to be defined.

B-Cell and Classical Hodgkin Lymphomas Associated With Immunodeficiency: 2015 SH/EAHP Workshop Report-Part 2

OBJECTIVES

The 2015 Workshop of the Society for Hematopathology/European Association for Haematopathology submitted small and large B-cell lymphomas (BCLs), including classical Hodgkin lymphoma (CHL), in the context of immunodeficiency.

METHODS

Clinicopathologic and molecular features were studied to explore unifying concepts in malignant B-cell proliferations across immunodeficiency settings.

RESULTS

Cases submitted to the workshop spanned small BCLs presenting as nodal or extranodal marginal zone lymphoma and lymphoplasmacytic lymphoma, Epstein-Barr virus (EBV) positive in 75% of cases. Submitted large BCLs formed a spectrum from diffuse large B-cell lymphoma (DLBCL) to CHL across immunodeficiency settings. Additional studies demonstrated overexpression of PD-L1 and molecular 9p24 alterations in the large BCL spectrum and across different immunodeficiency settings.

CONCLUSIONS

Small BCLs occur in all immunodeficiency settings, and EBV positivity is essential for their recognition as immunodeficiency related. Large BCLs include a spectrum from DLBCL to CHL across all immunodeficiency settings; immunohistochemical and molecular features are suggestive of shared pathogenetic mechanisms involving PD-L1 immune checkpoints.

B-cell Non-Hodgkin Lymphomas with Plasmacytic Differentiation

B-cell non-Hodgkin lymphomas with plasmacytic differentiation are a diverse group of entities with extremely variable morphologic features. Diagnostic challenges can arise in differentiating lymphoplasmacytic lymphoma from marginal zone lymphoma and other low-grade B-cell lymphomas. In addition, plasmablastic lymphomas can be difficult to distinguish from diffuse large B-cell lymphoma or other high-grade lymphomas. Judicious use of immunohistochemical studies and molecular testing can assist in appropriate classification.

Nodal marginal zone lymphoma: Clinical features, diagnosis, management and treatment

Nodular marginal zone lymphoma (NMZL) is a small B-cell lymphoma involving only lymph nodes and is the least common form of MZL constituting about 10% of cases. Patients usually present with advanced disease which must be distinguished from extranodal MZL with lymph node spread. NMZL shares cytological and immunophenotypic features with MALT and splenic MZL, but has a less favorable prognosis than these two categories. It occurs mostly in adults and pediatric cases are rare. Different therapeutic approaches have been used in NMZL, but because of the small patient numbers involved, more definitive treatment is still anticipated. Recent studies suggest that it probably represents a separate entity within the broader indolent lymphoma category. In NMZL there is an emerging need to utilize novel agents, already available for indolent lymphomas. Prospective studies are required to evaluate their therapeutic efficacy for NMZL in the future.

Transformation of marginal zone lymphoma (and association with other lymphomas)

Marginal zone lymphomas (MZL) are a diverse group of indolent lymphoproliferative disorders that comprise three subtypes: nodal, splenic and mucosal associated marginal zone lymphomas (MALT). Histologic transformation (HT) to an aggressive lymphoma is a rare event that can occur in any subtype, and at lower frequency compared to other indolent non Hodgkin lymphomas (NHL) like follicular lymphoma. There are few data directly associated with risk and prognosis of transformation in MZL. However, recent advances in the understanding of molecular and genetic features of MALT have contributed to an evolving appreciation of HT in this disease. Optimal treatment of HT of MZL remains unknown. Much of the approach to managing transformed MZL is extrapolated from other indolent NHLs.

Molecular pathogenesis of splenic and nodal marginal zone lymphoma

Genomic studies have improved our understanding of the biological basis of splenic (SMZL) and nodal (NMZL) marginal zone lymphoma by providing a comprehensive and unbiased view of the genes/pathways that are deregulated in these diseases. Consistent with the physiological involvement of NOTCH, NF-κB, B-cell receptor and toll-like receptor signaling in mature B-cells differentiation into the marginal zone B-cells, many oncogenic mutations of genes involved in these pathways have been identified in SMZL and NMZL. Beside genetic lesions, also epigenetic and post-transcriptional modifications contribute to the deregulation of marginal zone B-cell differentiation pathways in SMZL and NMZL. This review describes the progress in understanding the molecular mechanism underlying SMZL and NMZL, including molecular and post-transcriptional modifications, and discusses how information gained from these efforts has provided new insights on potential targets of diagnostic, prognostic and therapeutic relevance in SMZL and NMZL.

A Basic Approach to Lymph Node and Flow Cytometry Fine-Needle Cytology

According to the World Health Organization (WHO), the new classification of lymphomas is mainly based on morphological, immunophenotypical, and molecular criteria. Consequently, this new approach has led from the substantial role that architecture played in the past to a secondary panel highlighting the role of fine-needle biopsy (FNB). Applied together with other ancillary techniques, such as flow cytometry (FC), FNB is a potential tool for the diagnosis of lymphomas, and enlarged lymph nodes represent an excellent target for the implementation of this technique. Despite the difficulties inherent in this technology, which might pose problems in differential diagnosis, in the majority of cases this joint work allows an accurate diagnosis of malignancy and even correct subcharacterization in routine lymphomas. Additionally, in selected cases, other molecular techniques like FISH and PCR can also be performed on FNB specimens, helping in the characterization and diagnosis of lymphomas. In this review, we discuss the basic aspects of the combination of FNB cytology and FC in the diagnosis and subclassification of lymphomas. The preanalytical phase is extensively discussed. The advantages, disadvantages, and technical limitations of this joint work are addressed in general and in terms of the accurate subclassification of lymphomas.

Recurrent mutations in genes involved in nuclear factor-κB signalling in nodal marginal zone lymphoma-diagnostic and therapeutic implications

AIMS

To investigate the spectrum of mutations in 20 genes involved in B-cell receptor and/or Toll-like receptor signalling resulting in activation of nuclear factor-κB (NF-κB) in 20 nodal marginal zone lymphomas (NMZLs), 20 follicular lymphomas (FLs), and 11 cases of B-cell lymphoma, unclassifiable (BCL-u).

METHODS AND RESULTS

Nodal marginal zone lymphomas were diagnosed according to strict criteria, including the expression of at least one putative marginal zone marker (MNDA and/or IRTA1). Cases that showed features of NMZL but did not fulfil all criteria were included as BCL-u. All FLs were required to have a BCL2 rearrangement. Mutations were found in: nine NMZLs, with recurrent mutations in TNFAIP3 and CD79B; 12 FLs, with recurrent mutations in TNFRSF14, TNFAIP3, and CARD11; and five cases of BCL-u, with recurrent mutations in TNFRSF14. TNFRSF14 mutations were present in FL and BCL-u, but not in any of the NMZLs. In the BCL-u group, TNFRSF14 mutations clustered with a FL immunophenotype.

CONCLUSIONS

These results suggest that TNFRSF14 mutations point towards a diagnosis of FL, and can be used in the sometimes difficult distinction between NMZL and FL, but to apply this in diagnostics would require confirmation in an independent cohort. In addition, the presence or absence of specific mutations in pathways converging on NF-κB could be important for decisions regarding targeted treatment.