Immunophenotypic variations in mantle cell lymphoma

The Use of CD200 in the Differential Diagnosis of B-Cell Lymphoproliferative Disorders

Background: B-Cell Lymphoproliferative Disorders (B-LPDs) are a group of heterogenous disorders characterised by the accumulation of B-cells in peripheral blood, bone marrow, lymph nodes and spleen. They have a variable disease course and outcome and many share similar features making differential diagnosis challenging. Therefore, accurate diagnosis is fundamental in particular for determining treatment options. Immunophenotyping by flow cytometry plays a crucial role in the diagnosis of B-LPDs. However, overlapping immunophenotyping patterns exist and the use of novel monoclonal antibodies has become increasingly important in immunophenotyping analysis. More recently differential expression of CD200 has been reported in various B-LPDs and that CD200 may improve the differentiation between chronic lymphocytic leukaemia (CLL) and mantle cell lymphoma (MCL). In this study CD200 expression is evaluated in different B-LPDs. Methods: A total of 100 samples were collected and analysed by immunophenotyping flow cytometry over a period of 1 year (2017-2018), by a panel of monoclonal antibodies including CD200. The percentage of CD200 and its expression intensity was evaluated and compared between different groups of B-LPDs. Results: All of the 50 cases of CLL expressed CD200 with moderate to bright intensity, 6 MCL cases lacked the expression of CD200. Furthermore, all 5 cases of hairy cell leukaemia (HCL) expressed CD200. Out of all B-LPDs evaluated, CD200 expression in HCL cases was noted to be the brightest. The other 39 cases were not found to be B-LPDs. Conclusion: CD200 has an important role in differentiating CLL from MCL, HCL has a consistent bright expression of CD200. By adding CD200 to the combinations of markers in routine testing panel, Immunophenotyping by flow cytometry can be an effective tool in the diagnosis of B-LPDs especially in cases with atypical immunophenotyping pattern. Our result support that CD200 can be added to routine testing panel as it is useful in differentiating them.

Unveiling the Prognostic Significance of BCL6+/CD10+ Mantle Cell Lymphoma: Meta-Analysis of Individual Patients and Systematic Review

Mantle cell lymphoma (MCL) is a type of non-Hodgkin lymphoma (NHL) characterized by a hallmark translocation of t (11; 14). CD10 negativity has been used to differentiate MCL from other NHL types; however, recently, there has been an increase in the number of reported cases of CD10-positive MCL. This warrants further investigation into this rarer immunophenotype and its clinical significance. BCL6, which is a master transcription factor for the regulation of cell proliferation and key oncogene in B cell lymphomagenesis, has been reported to have co-expression with CD10 in MCL. The clinical significance of this aberrant antigen expression remains unknown. We conducted a systematic review by searching four databases and selected five retrospective analyses and five case series. Two survival analyses were conducted to determine if BCL6 positivity conferred a survival difference: 1. BCL6+ vs. BCL6- MCL. 2. BCL6+/CD10+ vs. BCL6-/CD10+ MCL. Correlation analysis was conducted to determine if BCL6 positivity correlated with the Ki67 proliferation index (PI). Overall survival (OS) rates were performed by the Kaplan-Meier method and log-rank test. Our analyses revealed that BCL6+ MCL had significantly shorter overall survival (median OS: 14 months vs. 43 months; p = 0.01), BCL6+/CD10+ MCL had an inferior outcome vs. BCL6+/CD10- MCL (median OS: 20 months vs. 55 months p = 0.1828), BCL6+ MCL had significantly higher percentages of Ki67% (Ki67% difference: 24.29; p = 0.0094), and BCL6 positivity had a positive correlation with CD10+ status with an odds ratio 5.11 (2.49, 10.46; p = 0.0000286). Our analysis showed that BCL6 expression is correlated with CD10 positivity in MCL, and BCL6 expression demonstrated an inferior overall survival. The higher Ki67 PI in BCL6+ MCL compared to BCL6- MCL further supports the idea that the BCL6+ immunophenotype may have prognostic value in MCL. MCL management should consider incorporating prognostic scoring systems adjusted for BCL6 expression. Targeted therapies against BCL6 may offer potential therapeutic options for managing MCL with aberrant immunophenotypes.

Unusual Presentation of Leukemic-Phase Mantle Cell Lymphoma: A Case Report

Mantle cell lymphoma (MCL) is a rare subtype of B-cell lymphoma that can present in a variety of ways, including the leukemic phase, where it can occasionally be mistaken for acute leukemia due to the unusually high or rapidly growing number of leukocytes and the presence of circulating cancer cells that are morphologically similar to leukemic blasts in myeloid or acute lymphoblastic leukemia. We present the case of an 83-year-old Yemeni woman with multiple comorbidities who presented with abdominal pain and constitutional symptoms. She was found to have diffuse lymphadenopathy on clinical and radiological assessments. Her white blood cell count at presentation was 221 × 10⁹/L with marked monocytosis (72.8%). Lymph node biopsy and bone marrow studies, including CCND1/IGH molecular studies, confirmed MCL, the pleomorphic subtype. The patient was deemed unfit for standard-of-care chemotherapy and was started on single-agent rituximab with a slow introduction to ibrutinib but succumbed to death after two weeks of ibrutinib 280 mg daily. This case serves as a reminder to keep an open mind and take into account atypical disease presentations when formulating differential diagnoses to prevent late diagnosis and any unnecessary intervention that can postpone appropriate therapy.

Clinicopathologic Features and Treatment of CD10-Positive Mantle Cell Lymphoma: A Case Report and Review of Literature

Mantle cell lymphoma (MCL) is a rare and aggressive non-Hodgkin’s B cell lymphoma characterized by the translocation t(11;14) (q13;32) and overexpression of CCND1. MCL is immunophenotypically identified as CD20⁺, CD5⁺, CyclinD1+, CD43⁺, CD10⁻, BCL6⁻, and CD23⁻. It is often distinguished from B cell lymphomas of germinal center cell origin by the absence of CD10 expression. Here we report the unique clinicopathologic features of a patient with CD10⁺ MCL with gastrointestinal involvement and review current literature identifying this unique immunophenotype.

Clinical and biological features of mantle cell lymphoma patients with co-expression of CD10 and BCL-6: a retrospective study

Background

Mantle cell lymphoma (MCL) with co-expression of CD10 and BCL-6 was scarcely reported, and its biological features were largely remained unknown. Thus, this study aimed to describe the clinical and biological features, as well as outcome of MCL patients with co-expression of CD10 and BCL-6.

Methods

A total of 104 cases of MCL who were admitted to our hospital between January 2011 and October 2018 were recruited. Those patients were diagnosed according to the 2016 World Health Organization (WHO) classification system for tumors of the hematopoietic and lymphoid tissues, in compliance with the results of cytomorphology and immunohistochemical analysis. Patients were followed up through telephone interviews, medical records. Differences in age, gender, leukocyte count, lactate dehydrogenase (LDH) level, beta-2 microglobulin (β2-MG) level and results of immunohistochemistry were analyzed. Then the event-free survival (EFS) rate and overall survival (OS) rate were performed by the Kaplan-Meier method and log-rank test.

Results

The results showed that, in total, 5 patients had superficial lymph node enlargement, 2 patients suffered from abdominal discomfort, and 1 patient’s red blood cell (RBC) count was abnormal at the time of diagnosis. All patients were in stage IV, 75% had bone marrow involvement, and 75% and 100% of patients had elevated levels of LDH and β2-MG, respectively. Three classic genes and five variants were involved in the 8 patients. MCL patients with the co-expression of CD10 and BCL-6 had higher Ki-67 index, white blood cell (WBC) count, LDH level, and β2-MG level than those of without co-expression of CD10 and BCL-6 (P=0.025, 0.038, 0.015, and 0.021, respectively). Besides, MCL patients with CD10 and BCL-6 co-expression had shorter OS and EFS (χ²=6.401 and 5.975; P=0.011 and 0.015, respectively), indicating patients’ susceptibility to get complex karyotype and TP53 abnormality.

Conclusions

MCL patients with co-expression of CD10 and BCL-6 were more likely to have bone marrow involvement, higher Ki-67 index, increased WBC count, and elevated levels of LDH and β2-MG at the time of diagnosis, then might has complex cytogenetic and poor prognosis.

How to Diagnose and Treat CD5-Positive Lymphomas Involving the Spleen

Patients with CD5-expressing lymphomas presenting with splenomegaly are frequently diagnosed with chronic lymphocytic leukemia. The most important differential diagnosis is mantle cell lymphoma, both in its classical and leukemic, non-nodal forms, given its prognostic and therapeutic implications. Other small B-cell neoplasms that frequently involve the spleen and occasionally express CD5 include the splenic marginal zone lymphoma, hairy cell leukemia and, rarely, lymphoplasmacytic lymphoma. The frequency of CD5 positivity depends in part on the sensitivity of the detection methods employed. Usually, a combination of morphological, immunophenotypic and molecular findings allows for a precise sub-classification of CD5-positive, low-grade B-cell lymphomas of the spleen. Some of these tumors may display a mixture of small and larger B cells, raising the possibility of more aggressive lymphomas, such as diffuse large B-cell lymphomas (DLBCL). Approximately 5-10% of DLBCL are CD5-positive and some may manifest as primary splenic lesions. When available, the morphology of DLBCL in the splenic tissue is distinctive and a leukemic picture is very rare. In conclusion, the appropriate morphological and clinical context assisted by flow cytometry panels and/or immunohistochemistry allows the differential diagnosis of CD5-positive, non-Hodgkin, B-cell lymphomas involving the spleen.

Detailed characterization of the transcriptome of single B cells in mantle cell lymphoma suggesting a potential use for SOX4

Mantle cell lymphoma (MCL) is a malignancy arising from naive B lymphocytes with common bone marrow (BM) involvement. Although t(11;14) is a primary event in MCL development, the highly diverse molecular etiology and causal genomic events are still being explored. We investigated the transcriptome of CD19⁺ BM cells from eight MCL patients at single-cell level. The transcriptomes revealed marked heterogeneity across patients, while general homogeneity and clonal continuity was observed within the patients with no clear evidence of subclonal involvement. All patients were SOX11⁺CCND1⁺CD20⁺. Despite monotypic surface immunoglobulin (Ig) κ or λ protein expression in MCL, 10.9% of the SOX11 + malignant cells expressed both light chain transcripts. The early lymphocyte transcription factor SOX4 was expressed in a fraction of SOX11 + cells in two patients and co-expressed with the precursor lymphoblastic marker, FAT1, in a blastoid case, suggesting a potential prognostic role. Additionally, SOX4 was found to identify non-malignant SOX11^– pro-/pre-B cell populations. Altogether, the observed expression of markers such as SOX4, CD27, IgA and IgG in the SOX11⁺ MCL cells, may suggest that the malignant cells are not fixed in the differentiation state of naïve mature B cells, but instead the patients carry B lymphocytes of different differentiation stages.

Clinicopathological and Immunohistochemical Profile of Mantle Cell Lymphoma: An Institutional Experience

Introduction

Mantle cell lymphoma (MCL) is a biologically aggressive B-cell non-Hodgkin lymphoma (NHL) with distinctive morphologic, immunophenotypic, and molecular characteristics. Differentiation from other chronic lymphoproliferative disorders is essential for prognostication.

Aim

This paper aims to study the clinicopathological features of MCL with emphasis on immunohistochemical features and disease correlation.

Method

To do so, clinicopathological characteristics from 21 cases of MCL (14 males, seven females, M:F=2:1) diagnosed in the last five years i.e. 2015 to 2020, were retrospectively reviewed and correlated with immunohistochemistry (IHC) data. Particularly those pertaining to cyclin D1, SRY-box transcription factor 11 (SOX11), cluster of differentiation (CD) 5, CD23, MIB E3 ubiquitin protein ligase 1 (MIB1), tumor protein 53 (TP53), c-myelocytomatosis oncogene product (c-MYC), multiple myeloma oncogene 1 (MUM1), mouse double minute 2 homolog (MDM2), and Epstein-Barr virus latent membrane protein 1 (EBV-LMP1) expression with its aberrations.

Observations

This study shows that MCL constituted 4.2% (21/500) of all NHLs with a mean age of 57.5 years (median 60 years, range 30 to 80 years). The disease was nodal in 19, and extranodal in the remaining two cases. 14 of 21 (67%) had generalized lymphadenopathy and 71% had bone marrow (BM) involvement. The nodal involvement was diffuse in 9/17 (53%), 8/21 (38%) had a blastoid morphology, and an in-situ MCL pattern was not seen in any of the cases selected for the study. Cyclin D1 immunoexpression correlated well with SOX11; CD5-negative in five cases; and CD23-positive in three cases. TP53 and c-MYC expression were noted in 17/19 (89.4%) and 8/17 (47%), respectively. MUM1 registered positive in six cases. None of the cases showed immunopositivity for MDM2 and EBV-LMP1.

Conclusion

In essence, this study indicates that morphological and immunophenotypic subclassification of mantle cell lymphoma with a wider panel of IHC markers is essential for understanding disease biology and better prognostication.

The relative expression levels of CD148 and CD180 on clonal B cells and CD148/CD180 median fluorescence intensity ratios are useful in the characterization of mature B cell lymphoid neoplasms infiltrating blood and bone marrow - Results from a single centre pilot study

INTRODUCTION

The categorization of mature B cell neoplasms (MBN) infiltrating blood and bone marrow are met with difficulties. The inclusion of CD148 and CD180 in the routine flow cytometry/FCM panels has been suggested to refine the diagnosis. We studied the discriminatory ability of CD148 and CD180 median fluorescence intensity(MFI), CD148/CD180 ratio and their expression relative to T cells (CD148^ab/T , CD180^ab/T ), neutrophils (CD148^ab/gr , CD180^ab/gr ) and normal B cells (CD148^ab/n , CD180^ab/n ) in the differentiation of mature B cell neoplasms (MBN) especially non-chronic lymphocytic leukaemia (CLL).

METHODOLOGY

The flow cytometric (FCM) expression of CD148 and CD180 was studied prospectively in 102 patients (non-CLL; n = 72); diagnosed by a comprehensive panel of immunophenotypic and cytogenetic studies. The MFI and ratios were statistically compared across MBNs by Mann-Whitney U test. Cut-off values, sensitivity and specificity were calculated for significant parameters by receiver operator characteristic curve.

RESULTS

CD180MFI > 4.35 showed 100% sensitivity and 90.9% specificity for a diagnosis of marginal zone lymphoma (MZL) while, CD148/180 > 5.15 was 100% specific and 81.8% sensitive for lymphoplasmacytic lymphoma. CD148^ab/T (>4.3; 100% specificity, 83.4% sensitivity) and CD148^ab/gr (>1.1; 100% sensitivity, 90% sensitivity) were useful for differentiating blastoid-mantle cell lymphoma/MCL from diffuse large B cell lymphoma; while CD148MFI (≥20.25), CD148^ab/T (>3.35) and CD148^ab/gr (>0.95) showed >90% specificity and sensitivity for distinguishing MCL from CLL. Pairwise analysis also showed a good discriminant function of various parameters for distinguishing SMZL from other MBNs like FL, MCL as well as CLL.

CONCLUSIONS

The current study shows an excellent utility of CD148MFI, CD180MFI, their ratio and relative expression levels in the subcategorization of immunophenotypically related MBNs.

What lies beneath: Cutaneous involvement of mantle cell lymphoma underlying an insect-bite-like reaction

Mantle cell lymphoma (MCL) is an uncommon subtype of mature B-cell non-Hodgkin lymphoma characterized by specific morphologic, immunophenotypic, and genetic characteristics, namely the t(11;14)(q13;q32) chromosomal translocation with resultant cyclin D1 overexpression. MCL has a generally aggressive course and is often widely disseminated at the time of diagnosis. Skin involvement is exceedingly rare and is seldom the first manifestation of MCL. We present a case of MCL in an 84-year-old man with cutaneous involvement as the first manifestation, discovered incidentally after biopsy of a persistent nodule believed to be an insect bite. This case not only serves to raise awareness of the possibility of MCL presenting in the skin but also to point out that MCL can have lesions with both an insect-bite-like reaction and a deeper dermal MCL infiltrate.

Genetic heterogeneity and prognostic impact of recurrent ANK2 and TP53 mutations in mantle cell lymphoma: a multi-centre cohort study

The molecular features of mantle cell lymphoma (MCL), including its increased incidence, and complex therapies have not been investigated in detail, particularly in East Asian populations. In this study, we performed targeted panel sequencing (TPS) and whole-exome sequencing (WES) to investigate the genetic alterations in Korean MCL patients. We obtained a total of 53 samples from MCL patients from five Korean university hospitals between 2009 and 2016. We identified the recurrently mutated genes such as SYNE1, ATM, KMT2D, CARD11, ANK2, KMT2C, and TP53, which included some known drivers of MCL. The mutational profiles of our cohort indicated genetic heterogeneity. The significantly enriched pathways were mainly involved in gene expression, cell cycle, and programmed cell death. Multivariate analysis revealed that ANK2 mutations impacted the unfavourable overall survival (hazard ratio [HR] 3.126; P = 0.032). Furthermore, TP53 mutations were related to worse progression-free survival (HR 7.813; P = 0.043). Among the recurrently mutated genes with more than 15.0% frequency, discrepancies were found in only 5 genes from 4 patients, suggesting comparability of the TPS to WES in practical laboratory settings. We provide the unbiased genetic landscape that might contribute to MCL pathogenesis and recurrent genes conferring unfavourable outcomes.

Genetic mutations and features of mantle cell lymphoma: a systematic review and meta-analysis

Mantle cell lymphoma (MCL) is an incurable rare subtype of non-Hodgkin lymphoma and is subject to relapse and therapeutic resistance. Molecular aberrations in MCL affect pathogenesis, prognosis, and therapeutic response. In this systematic review, we searched 3 databases and selected 32 articles that described mutations in MCL patients. We then conducted a meta-analysis using a Bayesian multiregression model to analyze patient-level data in 2127 MCL patients, including prevalence of mutations. In tumor or bone marrow samples taken at diagnosis or baseline, ATM was the most frequently mutated gene (43.5%) followed by TP53 (26.8%), CDKN2A (23.9%), and CCND1 (20.2%). Aberrations were also detected in IGH (38.4%) and MYC (20.8%), primarily through cytogenetic methods. Other common baseline mutations were NSD2 (15.0%), KMT2A (8.9%), S1PR1 (8.6%), and CARD11 (8.5%). Our data also show a change in mutational status from baseline samples to samples at disease progression and present mutations of interest in MCL that should be considered for future analysis. The genes with the highest mutational frequency difference (>5%) are TP53, ATM, KMT2A, MAP3K14, BTK, TRAF2, CHD2, TLR2, ARID2, RIMS2, NOTCH2, TET2, SPEN, NSD2, CARD11, CCND1, SP140, CDKN2A, and S1PR1. These findings provide a summary of the mutational landscape of MCL. The genes with the highest change in mutation frequency should be included in targeted next-generation sequencing panels for future studies. These findings also highlight the need for analysis of serial samples in MCL. Patient-level data of prevalent mutations in MCL provide additional evidence emphasizing molecular variability in advancing precision medicine initiatives in MCL.

Mantle cell lymphoma

MCL is a well-characterized generally aggressive lymphoma with a poor prognosis. However, patients with a more indolent disease have been reported in whom the initiation of therapy can be delayed without any consequence for the survival. In 2017 the World Health Organization updated the classification of MCL describing two main subtypes with specific molecular characteristics and clinical features, classical and indolent leukaemic nonnodal MCL. Recent research results suggested an improving outcome of this neoplasm. The addition of rituximab to conventional chemotherapy has increased overall response rates, but it did not improve overall survival compared to chemotherapy alone. The use of intensive frontline therapies including rituximab and consolidation with autologous stem cell transplantation ameliorated response rate and prolonged progression-free survival in young fit patients, but any impact on survival remains to be proven. Furthermore, the optimal timing, cytoreductive regimen and conditioning regimen, and the clinical implications of achieving a disease remission even at molecular level remain to be elucidated. The development of targeted therapies as the consequence of better understanding of pathogenetic pathways in MCL might improve the outcome of conventional chemotherapy and spare the toxicity of intense therapy in most patients. Cases not eligible for intensive regimens, may be considered for less demanding therapies, such as the combination of rituximab either with CHOP or with purine analogues, or bendamustine. Allogeneic SCT can be an effective option for relapsed disease in patients who are fit enough and have a compatible donor. Maintenance rituximab may be considered after response to immunochemotherapy as the first-line strategy in a wide range of patients. Finally, since the optimal approach to the management of MCL is still evolving, it is critical that these patients are enrolled in clinical trials to identify the better treatment options.

Pleomorphic Mantle Cell Lymphoma of the Tongue Base Presenting With Dysphagia

Objectives

We aim to increase awareness of pleomorphic mantle cell lymphoma as a rare, but aggressive form of lymphoma with propensity for recurrence in secondary locations.

Methods

We report the case of a 70-year-old man who presented with chronic post-nasal drainage, dysphagia, and voice changes caused by a tongue base mass.

Results

Partial excision and pathology showed a pleomorphic mantle cell lymphoma, and radiation treatment was completed. A regional recurrence was detected 3 years later and treated with radiation. He had no evidence of disease 17 months after treatment of the recurrence and is under close surveillance.

Conclusions

Pleomorphic mantle cell lymphoma is an aggressive subtype of non-Hodgkin lymphoma that can affect the head and neck. Confirming the diagnosis with immunotyping and genotyping from fresh specimens can guide appropriate treatment and then close clinical follow-up.

Immunophenotypic Characterization of Canine Splenic Follicular-Derived B-Cell Lymphoma

Marginal zone lymphoma (MZL) and mantle cell lymphoma (MCL) belong to a subgroup of indolent B-cell lymphomas most commonly reported in the canine spleen. The goal of this study was to characterize the immunophenotype of splenic MZL and MCL in comparison to their human counterparts. Ten MCLs and 28 MZLs were selected based on morphology. A tissue microarray was generated, and expression of CD3, CD5, CD10, CD45, CD20, CD79a, Pax-5, Bcl-2, Bcl-6, cyclin D1, cyclin D3, MCL-1, MUM-1, and Sox-11 was evaluated. Neoplastic cells in all MCLs and MZLs were positive for CD5, CD20, CD45, CD79a, and BCL2 and negative for CD3, CD10, Bcl-6, cyclin D1, and cyclin D3. Positive labeling for Pax-5 was detected in 8 of 10 MCLs and 26 of 28 MZLs. Positive labeling for MUM-1 was detected in 3 of 10 MCLs, and 27 of 28 MZLs were positive for MUM-1. No MCLs but 8 of 24 MZLs were positive for MCL-1. Canine splenic MZL and MCL have a similar immunophenotype as their human counterparts. However, human splenic MCL overexpresses cyclin D1 due to a translocation. A similar genetic alteration has not been reported in dogs. In addition, in contrast to human MZL, canine splenic MZL generally expresses CD5. Following identification of B vs T cells with CD20 and CD3, a panel composed of BCL-2, Bcl-6, MUM-1, and MCL-1 combined with the histomorphological pattern can be used to accurately diagnose MZL and MCL in dogs. Expression of Bcl-2 and lack of MCL-1 expression in MCL may suggest a therapeutic benefit of BCL-2 inhibitors in canine MCL.

An integrated flow cytometry analysis of 286 mature B cell neoplasms identifies CD13 as a useful marker for diagnostic subtyping

INTRODUCTION

CD13 is a myeloid associated antigen, which may be expressed by a subset of B cell lymphomas; however, the significance of its expression along with other B cell associated antigens is not well characterized.

METHODS

Two hundred and eighty-six mature B cell neoplasms with flow cytometric analysis performed at the time of diagnosis were identified. Expression of CD13, CD45, CD19, CD20, CD5, CD10, CD38, CD22, CD23, FMC7, and kappa and lambda light chains was assessed for each case and correlated with clinicopathologic features.

RESULTS

CD13 expression was associated specifically with cases of lymphoplasmacytic lymphoma (LPL) (16/26)- and FMC7-positive chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) (11/30). No cases of follicular lymphoma (FL) expressed CD13 (0/48). Across all B cell neoplasms, CD13 expression positively correlated with FMC7 co-expression and kappa light chain restriction and negatively correlated with CD10 co-expression and lambda light chain restriction. No significant association of CD13 with overall or disease free survival in B cell neoplasms was seen.

CONCLUSION

CD13 expression is present more often in LPL- and FMC7-positive CLL/SLL than other mature B cell lymphoma subtypes and absent in cases of FL and may be a useful feature for diagnostic subtyping.

Immunophenotypic Variations in Mantle Cell Lymphoma and Their Impact on Clinical Behavior and Outcome

Context.—

Immunophenotypic variations in mantle cell lymphoma (MCL) from the classic CD5+/CD10−/CD23−/FMC-7+ immunophenotype have been reported in the literature, but correlation with clinical behavior and outcome has not been fully studied.

Objective.—

To investigate clinicopathologic and prognostic differences between immunophenotypically aberrant MCL and immunophenotypically typical MCL.

Design.—

We evaluated differences in clinical presentation, laboratory parameters, prognostic indices, response to initial treatment, and progression-free and overall survival between patients with aberrant MCL and patients with immunophenotypically typical MCL.

Results.—

There were 158 patients with newly diagnosed cyclin D1 or t(11;14)(q13;q32)+ MCL identified in the original search, of which, 29 patients (18%) showed immunophenotypic aberrancies, with CD23 coexpression being the most common. When compared with 33 randomly selected patients with immunophenotypically typical MCL, statistically significant differences were seen in white blood cell counts (P = .02), in the presence of absolute lymphocytosis (P = .03), in the MCL International Prognostic Index score (P = .02), and in response to initial treatment (P = .04). The “immunophenotypic status” of the MCL was the only independent factor associated with response to treatment (P = .05), but not with the MCL International Prognostic Index score, absolute lymphocytosis, or white blood cell count. No significant differences were seen for progression-free or overall survival.

Conclusions.—

Immunophenotypic variations in MCL are associated with differences in clinical presentation and response to therapy when compared with immunophenotypically typical MCL. However, with current intensive frontline immunochemotherapy, immunophenotypic aberrations do not appear to affect progression-free or overall survival.

A Unique Case of Blastoid Variant of Mantle Cell Lymphoma with an Aberrant CD5-/CD10+/Bcl-6+/CD56+ Immunophenotype: A Case Report

The neural adhesion molecule CD56 is normally expressed on natural killer cells and subsets of T cells and is commonly found in hematolymphoid neoplasms. Expression of CD56 is very rare in B-cell lymphoma and most reported CD56-positive cases were diffuse large B-cell lymphomas. Cases of CD56-positive mantle cell lymphoma (MCL) have not previously been described in the literature. We present a case of CD56-positive MCL. To the best of our knowledge, this is the first case report of MCL expressing CD56.

Mantle cell lymphoma in the era of precision medicine-diagnosis, biomarkers and therapeutic agents

Despite advances in the development of clinical agents for treating Mantle Cell Lymphoma (MCL), treatment of MCL remains a challenge due to complexity and frequent relapse associated with MCL. The incorporation of conventional and novel diagnostic approaches such as genomic sequencing have helped improve understanding of the pathogenesis of MCL, and have led to development of specific agents targeting signaling pathways that have recently been shown to be involved in MCL. In this review, we first provide a general overview of MCL and then discuss about the role of biomarkers in the pathogenesis, diagnosis, prognosis, and treatment for MCL. We attempt to discuss major biomarkers for MCL and highlight published and ongoing clinical trials in an effort to evaluate the dominant signaling pathways as drugable targets for treating MCL so as to determine the potential combination of drugs for both untreated and relapse/refractory cases. Our analysis indicates that incorporation of biomarkers is crucial for patient stratification and improve diagnosis and predictability of disease outcome thus help us in designing future precision therapies. The evidence indicates that a combination of conventional chemotherapeutic agents and novel drugs designed to target specific dysregulated signaling pathways can provide the effective therapeutic options for both untreated and relapse/refractory MCL.

CD10-positive mantle cell lymphoma: clinicopathologic and prognostic study of 30 cases

Mantle cell lymphoma is usually negative for CD10 which is useful in distinguishing MCL from other CD10 + B cell lymphomas. Here we assessed the clinicopathologic features of 30 cases of CD10+ MCL, the largest series to date in the English literature, and compared them with a group of 212 typical MCL cases (CD5+, CD10-negative, CD23-negative, cyclin D1+). The 30 patients with CD10+ MCL included 17 men and 13 women with a median age of 68 years. Compared with CD10-negative MCL, patients with CD10+ MCL showed a lower male predominance (p = 0.01), more often had a diffuse growth pattern (p = 0.04) and blastoid/pleomorphic morphology (p < 0.0001), and more often showed BCL6 expression (p = 0.009). In all MCL patients, CD10 expression was not associated with overall survival (OS) (p = 0.16). However, in more aggressive subsets of MCL patients including those with high Ki67 (> 60%), blastoid/pleomorphic morphology, or high MCL International Prognostic Index (MIPI), CD10 expression was associated with a worse OS (p = 0.003, 0.04, and 0.001, respectively). High Ki67 (> 60%), blastoid/pleomorphic morphology, and high MIPI were also been identified as poor prognostic factors patients with in CD10+ MCL (p = 0.001, 0.0003, and 0.01, respectively). In summary, CD10+ MCL more often has a diffuse growth pattern, blastoid/pleomorphic morphology, and BCL6 expression. In MCL patients with a high Ki-67 (> 60%), blastoid/pleomorphic morphology, or high MIPI, CD10 expression contributes to an even worse prognosis. MCL should be included in the differential diagnosis of CD10 + B cell lymphomas.

Mantle cell lymphoma: involvement of nodal and extranodal sites in the head and neck, with multifocal oral lesions

Mantle cell lymphoma (MCL) is a malignant B-cell neoplasm, which comprises monomorphic and small- to medium-sized mantle zone-derived lymphoid cells. It is characterized by chromosomal translocation t(11;14)(q13;q32) and CCND1 truncation, resulting in cell cycle deregulation. It is an aggressive type of non-Hodgkin lymphoma with a propensity to present with extranodal involvement. This study shows the case of an 80-year-old Caucasian male who complained of a 2-month progressive swelling on the right side of his face. The magnetic resonance imaging exam showed multifocal involvement of the head and neck, including oral manifestations, bilateral parotid glands, palate, tongue, and floor of the mouth. An incisional biopsy of the tumor mass was performed. The morphological and immunophenotypic findings were consistent with the diagnosis of MCL. The patient died 4 months later, without any chance of undergoing a therapeutic approach. Although MCL is a rare condition, it should be subjected to a differential diagnosis when affecting the maxillofacial area. Imaging exams and both immunohistochemical and morphological analyses are needed to reach the correct diagnosis. Here, we present an unusual MCL with multifocal involvement of the head and neck.

Aberrant expression of CD10 and BCL6 in mantle cell lymphoma

AIMS

Mantle cell lymphoma (MCL) is characterized by distinctive histological and molecular features. Aberrant expression of BCL6 and CD10 has been reported occasionally, but the biological features of such cases are largely unknown. This study aimed to define the epidemiological, histological and cytogenetic characteristics of BCL6 and CD10-positive MCLs, also investigating possible biological features.

METHODS AND RESULTS

A total of 165 cases of cyclin D1 and t(11;14)(q13;q34)-positive MCLs were studied for CD10 and BCL6 immunohistochemical expression, which was documented in 26 of 165 (15.8%) cases (BCL6 17 of 165; CD10 11 of 165; BCL6 and CD10 co-expression two of 165). CD10-positivity was significantly more frequent in females (63.3%; P < 0.01). Either expression correlated significantly with higher mean proliferation index and higher prevalence of MUM1 positivity (P < 0.05). Fluorescence in-situ hybridization (FISH) for BCL6 (3q27) gene derangements was performed on the BCL6- and CD10-positive cases and 98 matched controls: amplifications were documented more frequently in BCL6-positive than -negative cases (50.0% versus 19.4% of cases) (P < 0.05). The mutational status of the variable immunoglobulin heavy chain genes (IGVH) was investigated by Sanger sequencing: five of the six successfully tested cases (83.3%) showed no somatic hypermutations.

CONCLUSIONS

Aberrant CD10 and BCL6 expression defines a subset of MCLs with higher mean Ki-67 index and higher prevalence of MUM1 expression. BCL6 protein positivity correlates with cytogenetic aberrations involving the BCL6 gene. Although examined successfully in few cases, the high prevalence of unmutated IGVH genes also points at a pregerminal cell origin for these phenotypically aberrant cases.

The Role of CD200 and CD43 Expression in Differential Diagnosis between Chronic Lymphocytic Leukemia and Mantle Cell Lymphoma

Objective:

Atypical chronic lymphocytic leukemia (CLL) is most frequently confused with mantle cell lymphoma (MCL). Several markers may contribute to the diagnosis of CLL. However, there is no consensus on which markers are needed to be used in flow cytometry for the diagnosis of CLL. The aim of the present study was to investigate the role of CD43 and CD200 markers in the differential diagnosis between CLL and MCL.

Materials and Methods:

To address this issue, 339 consecutive patients with CLL and MCL were included in the flow cytometry lymphoproliferative disease panel for evaluation of CD43 and CD200 expressions, but not in the Matutes scoring system.

Results:

CD200 was expressed in 97.3% of atypical CLL cases, whereas it was dimly expressed in only 6.1% of MCL cases. CD43 expression was 95.7% in atypical CLL cases. In the MCL cases, its expression rate was 39.4%.

Conclusion:

CD43 and CD200 were found to be more valuable markers than CD22, CD79b, and FMC7. CD43 and CD200 could also be considered as definitive markers in atypical CLL patients, for whom the Matutes scoring system remains ineffective.

Cutaneous mantle cell lymphoma: a clinicopathologic review of 10 cases

Cutaneous mantle cell lymphoma (MCL) is exceedingly rare, almost always occurring as a dissemination of systemic MCL. To date, only 32 cases have been described. We report a series of 10 cases of MCL in the skin, and provide a comprehensive clinicopathologic review with clinical follow-up. Our cases occurred in older individuals (mean age = 70) and were more frequently in men (90%). Half of them presented in the head and neck region as a mass/nodule, and the remainder in the trunk and extremities as nodules. All patients have stage IV disease. In two of the 10 cases (20%) the cutaneous lesions preceded the diagnosis of disseminated disease. In two of the seven cases with available clinical follow-up information (33%) the skin was immediately involved after the diagnosis of MCL, and in three of the seven the skin was the first site of recurrence (mean interval = 57 months). The mean time to recurrence of the disease was 45.4 months and the overall survival was 66.3 months. Histologically six out of 10 cases (60%) had either pleomorphic or blastoid morphology (four out of 10 and two out of 10, respectively). The mean number of mitoses per 10 high-power fields was 18.44. While nine out of 10 cases expressed cyclin-D1, one case was not positive for cyclin-D1 but did label with SOX-11. Limited cytogenetic data showed trisomy 14 in one case, in addition to the t(11;14) translocation.

Clinicopathologic features and management of blastoid variant of mantle cell lymphoma

The blastoid variant of mantle cell lymphoma (MCL), which accounts for less than one-third of MCL, may arise de novo or as a transformation from the classical form of MCL. Blastoid variant, which predominantly involves men in their sixth decade, has frequent extranodal involvement (40-60%), stage IV disease (up to 85%) and central nervous system (CNS) involvement. Diagnosis relies on morphological features and is challenging. Immunophenotyping may display CD23 and CD10 positivity and CD5 negativity in a subset. Genetic analysis demonstrates an increased number of complex genetic alterations. Blastoid variant responds poorly to conventional chemotherapy and has a short duration of response. Although the optimal therapy remains to be established, CNS prophylaxis and the use of aggressive immunochemotherapy followed by autologous stem cell transplant may prolong the remission rate and survival. Further studies are crucial to expand our understanding of this disease entity and improve the clinical outcome.

Flow cytometric analysis of lymphoid enhancer-binding factor 1 in diagnosis of chronic lymphocytic leukemia/small lymphocytic lymphoma

OBJECTIVES

Nuclear overexpression of lymphoid enhancer-binding factor 1 (LEF1) assessed by immunohistochemistry has been shown to be highly associated with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) among small B-cell lymphomas. The purpose of this study was to evaluate the utility of flow cytometric analysis of LEF1 in the diagnosis of CLL/SLL.

METHODS

Normal peripheral blood was used to validate the test. Flow cytometric analysis of LEF1 was performed in 64 patient samples qualitatively and quantitatively by comparing the staining intensity and the ratios of the median fluorescence intensities (MFIs) of LEF1 in B cells of interest to the internal reference cell populations. The results were correlated with the pathologic diagnosis.

RESULTS

Proper sample processing ensured sufficient separation of positive LEF1 staining in T cells from negative staining in normal B and natural killer (NK) cells. Qualitative analysis of patient samples showed that all 25 cases of CLL/SLL but none of the other small B-cell lymphomas were positive for LEF1. Using a B/NK MFI ratio of 1.5 and B/T MFI ratio of 0.45 separated CLL/SLL cases from non-CLL lymphomas.

CONCLUSIONS

Flow cytometric analysis of LEF1 is sufficient to differentiate CLL/SLL from other small B-cell lymphomas and may serve as a useful tool in the diagnosis of CLL/SLL.

Detection of minimal residual disease in mantle cell lymphoma-establishment of novel eight-color flow cytometry approach

BACKGROUND

Minimal residual disease (MRD) detection is an essential tool for therapy response assessment in a considerable number of hematooncologic disorders, including mantle cell lymphoma (MCL). Flow cytometry (FCM) ranks among the most effective approaches, which allows rapid sample processing and compete successfully with highly sensitive molecular methods like polymerase chain reaction. Because FCM is ordinarily applied to detect MRD in B-lineage diseases like chronic lymphocytic leukemia, a similar method could be used in MCL. We decided to test our novel eight-color FCM approach in MCL MRD detection.

METHODS

Using an eight-color FCM protocol designed by us, the expression of 24 selected surface antigens in a cohort of 30 patients with newly diagnosed leukemic MCL and 20 normal controls were compared to establish markers that can reliably distinguish normal B-lymphocytes from the MCL population. The sensitivity of the designed protocol was tested using serial dilution studies.

RESULTS

Although MCL presents high immunophenotypic variability, the combination of CD20/23/5/19/200/62L/3/45 seems to be very favorable in flow cytometric MRD measurement.

CONCLUSIONS

Our eight-color FCM protocol could easily detect MRD in MCL patients, and reaches a sensitivity of up to 2 × 10(-4) .

Atypical case of B-cell Chronic Lymphocytic Leukemia presenting with extreme hyperleukocytosis / Hiperleucocitoză extremă într-un caz atipic de leucemie limfatică cronică cu celulă B

Very few cases of chronic lymphocytic leukemia (CLL) presenting with extreme hyperleukocytosis are reported in the literature. We describe the case of a 66 years old woman, with newly diagnosed CLL presenting with extreme hyperleukocytosis of 774.2 x 109/liter, Rai stage III and Binet stage C. The patient has no comorbidities and the CIRS score (cumulative illness rating scale) is well below 6, with normal creatinine clearance. Some other interesting aspects related with this case are the atypical immunophenotype, the expression of Cyclin D1, and the B hepatitis viral infection, which made her diagnosis and treatment challenging. The patient was tested for NOTCH1 mutation and it was positive. There is important evidence that NOTCH1 mutations are associated with rapidly progressive disease and resistance to treatment. The distinction of CLL from mantle cell lymphoma (MCL) is not always easy because some MCLs may mimic CLL clinically, histologically, and/or phenotypically. The hepatitis B prophylaxis for viral reactivation was not available an in the end the patient was treated only with fludarabine and cyclophosphamide, without rituximab. CD200 should be introduced in the routine panel for flow cytometry to distinguish CLL from mantle cell lymphoma and NOTCH1 mutation is associated with poor prognosis and should be evaluated at diagnosis. CLL with extreme hyperleukocytosis presentation is very rare and sometimes an atypical CLL may represent a diagnostic pitfall.

Cytopathology in the diagnosis of lymphoma

FNA is a simple, safe, and an inexpensive sampling technique that plays an important role in the evaluation of lymphadenopathy. The key to enhancing the accuracy of FNA diagnosis of lymphoma is the multi parameter approach in which the cytomorphologic features are evaluated in correlation with the results of ancillary studies and clinical context. A full understanding of the current lymphoma classification, clinical features associated with each lymphoma subtype and the impact of the diagnosis on patient management is essential in FNA diagnosis of lymphoma. It is also important to recognize the limitations of FNA in the primary diagnosis of some subtypes of lymphoma, and tissue biopsy should be recommended for a definitive diagnosis and subclassification in such cases.

CD200 has an important role in the differential diagnosis of mature B-cell neoplasms by multiparameter flow cytometry

BACKGROUND

Multiparameter flow cytometry is a useful tool for the diagnostic evaluation of mature B-cell neoplasms (MBN). Recently, it has been shown that CD200 may improve the distinction between chronic lymphocytic leukemia (CLL; CD200+) and mantle cell lymphoma (MCL; CD200-), but the role of CD200 expression in atypical CLL and other MBN remains to be established.

METHODS

To address this issue, we investigated the expression of CD200 in 159 consecutive cases of MBN.

RESULTS

CD200 was strongly expressed in CLL and was revealed to be an excellent marker to distinguish CLL from MCL, even in cases of atypical CLL. However, lack of CD200 was not an exclusive finding of MCL, being also observed in other MBNs. Furthermore, CD200 was highly expressed in hairy cell leukemia, being useful in the differential diagnosis of lymphomas with villous lymphocytes. Herein, we propose an algorithm to classify CD5+ MBNs based on the expression of CD200, CD11c, heavy chain immunoglobulins, and Matutes score.

CONCLUSIONS

These results expand the understanding of the CD200 expression in MBNs, giving further support for the inclusion of this marker in the routine investigation by flow cytometry.

Transformation of indolent mantle cell lymphoma to pleomorphic mantle cell lymphoma: case report and review of clinical and morphologic variants

We report a case of indolent mantle cell lymphoma with progression to pleomorphic mantle cell lymphoma 8 years after initial presentation. The first lymph node biopsy showed expanded mantle zones composed of uniformly small B lymphocytes. A cyclin D1 immunohistochemical stain was negative and the patient was observed. Eight years later, the patient developed symptomatic splenomegaly. Microscopic examination of the spleen revealed expanded mantle zones with an increased number of large cells with irregular nuclear contours. Immunohistochemistry for cyclin D1 was positive. A repeat cyclin D1 immunohistochemical staining performed on the initial lymph node biopsy was positive, indicating an inadequate initial study. Immunoglobulin heavy-chain gene rearrangement studies confirmed clonal identity. A revised diagnosis of indolent mantle cell lymphoma with progression to pleomorphic mantle cell lymphoma was rendered. The differential diagnosis of mantle cell lymphoma, including clinical and morphologic variants, is discussed.

Chronic lymphocytic leukemia/small lymphocytic lymphoma with cyclin D1 positive proliferation centers do not have CCND1 translocations or gains and lack SOX11 expression

Cyclin D1 expression, usually absent in chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), has been described in the proliferation centers (PC) of some CLL/SLL. The prevalence of this finding is uncertain, as is the explanation for its occurrence and whether these cases have any other unique features. Cyclin D1 immunohistochemical staining was therefore investigated in 57 extramedullary CLL/SLL biopsies. In 6 cases, cyclin D1 immunofluorescence followed by CCND1 fluorescence in situ hybridization (FISH) and PC targeted analysis was performed using a Bioview Duet system. Excluding the prospectively selected cases that had the targeted FISH studies, cyclin D1+ PC were identified in 20% of cases. The cyclin D1+ CLL did not appear pathologically or phenotypically distinctive, though 46% had an interfollicular growth pattern. The cyclin D1+ PCs were SOX11- and lacked CCND1 translocations and gains in 5 of 5 informative cases. The recognition of cyclin D1 expression in PC of a significant minority of CLL/SLL can be a diagnostic aid and should not lead to the diagnosis of focal mantle cell lymphoma.

Establishment and characterization of therapy-resistant mantle cell lymphoma cell lines derived from different tissue sites

Mantle cell lymphoma (MCL) is a rare but aggressive form of B cell non-Hodgkin lymphoma in which therapy resistance is common. New therapeutic options have extended survival in refractory MCL but have not provided durable remission. Tools are needed to assess the molecular and genetic changes associated with therapy resistance. Therefore, therapy-resistant MCL cell lines were established from the liver, kidney and lungs of human Granta 519-bearing NOD-SCID (non-obese diabetic-severe combined immunodeficiency) mice following treatment with CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) chemotherapy in combination with bortezomib. The cytomorphologies, immunophenotypes, growth patterns in semi-solid agar, cytogenetic profiles and gene expression differences between these cell lines were characterized to identify major changes associated with therapy resistance. Therapy-resistant cell lines exhibit more aggressive growth patterns and markedly different gene expression profiles compared to parental Granta 519 cells. Thus, these stable therapy-resistant cell lines are useful models to further study the molecular basis of drug resistance and to identify clinically relevant molecular targets in MCL.

Early lesions in lymphoid neoplasia: Conclusions based on the Workshop of the XV. Meeting of the European Association of Hematopathology and the Society of Hematopathology, in Uppsala, Sweden

The increasing use of immunophenotypic and molecular techniques on lymphoid tissue samples without obvious involvement by malignant lymphoma has resulted in the increased detection of "early" lymphoid proliferations, which show some, but not all the criteria necessary for a diagnosis of malignant lymphoma. In most instances, these are incidental findings in asymptomatic individuals, and their biological behaviour is uncertain. In order to better characterize these premalignant conditions and to establish diagnostic criteria, a joint workshop of the European Association for Haematopathology and the Society of Hematopathology was held in Uppsala, Sweden, in September 2010. The panel reviewed and discussed more than 130 submitted cases and reached consensus diagnoses. Cases representing the nodal equivalent of monoclonal B-cell lymphocytosis (MBL) were discussed, as well as the "in situ" counterparts of follicular lymphoma (FL) and mantle cell lymphoma (MCL), topics that also stimulated discussions concerning the best terminology for these lesions. The workshop also addressed the borderland between reactive hyperplasia, and clonal proliferations such as pediatric marginal zone lymphoma and pediatric FL, which may have very limited capacity for progression. Virus-driven lymphoproliferations in the grey zone between reactive lesions and manifest malignant lymphoma were covered. Finally, early manifestations of T-cell lymphoma, both nodal and extranodal, and their mimics were addressed. This workshop report summarizes the most important conclusions concerning diagnostic features, as well as proposals for terminology and classification of early lymphoproliferations and tries to give some practical guidelines for diagnosis and reporting.

Histopathology of mantle cell lymphoma

Mantle cell lymphoma (MCL) is a relatively rare lymphoma, accounting for less than 10% only of all lymphomas. Its morphology is quite homogeneous, but it varies strikingly in about 10% of the cases, making the diagnosis of MCL challenging for histopathologists. The definition of the disease was greatly influenced by the discovery of the translocation t(11;14)(q13,q32), which juxtaposes the cyclin D1 and the immunoglobulin heavy chain genes and is present in the vast majority of MCL cases. The introduction of monoclonal antibodies for the detection of cyclin D1 expression into the diagnostic procedure substantially improved the reproducibility and reliability of the pathological diagnosis. However, new challenges for histopathologists have arisen over the last years, among which are the detection of cyclin D1-negative MCL cases and clinically relevant prognostic subgroups.

Is there a role for "watch and wait" in patients with mantle cell lymphoma?

Up to one third of patients with mantle cell lymphoma (MCL) may be observed for a period of months to years before developing indications for therapy. Importantly, observational studies suggest that this approach has no apparent negative impact on their overall survival. Although there is broad agreement on which patients require early therapy, identification of patients with less aggressive disease can be challenging. Clinical tools such as the Mantle Cell International Prognostic Index (MIPI) and Ki67 are effective at predicting survival but may not always correspond with indications for treatment. Research tools such as the proliferative signature are attractive but have yet to be evaluated in this context. Physicians, therefore, must make decisions regarding therapy based on the best available evidence. In the absence of evidence that treatment necessarily influences long-term survival, it may be reasonable to observe selected patients for a period of time prior to making definitive treatment-related decisions. Collaborative efforts are required to better understand the pathophysiology of the disease and potentially identify patients amenable to "watch and wait." Similarly, patients with less aggressive MCL may be an ideal group in which to evaluate novel treatment approaches.

Diagnostic usefulness and prognostic impact of CD200 expression in lymphoid malignancies and plasma cell myeloma

The membrane glycoprotein MRC OX-2 (CD200) is expressed in several lymphoid malignancies. However, the diagnostic usefulness and potential prognostic importance of CD200 expression have not been rigorously examined. We show that CD200 is uniformly expressed in chronic lymphocytic leukemia (CLL) and absent in mantle cell lymphoma (MCL). It is important to note that expression of CD200 is retained even in CLLs with immunophenotypic aberrancies, making CD200 a particularly useful marker for discrimination between these cases and MCL. CD200 is expressed in nearly all precursor B-lymphoblastic leukemias, with aberrant overexpression or underexpression compared with normal B-cell progenitors in 55% of cases. More than 70% of plasma cell myelomas (PCMs) expressed CD200, and loss of CD200 expression in PCM may be associated with more clinically aggressive disease. CD200 is expressed in several hematolymphoid neoplasms. Analysis of its expression has several diagnostic and potentially prognostic applications in the flow cytometric evaluation of lymphoid malignancies.

Nuclear overexpression of lymphoid-enhancer-binding factor 1 identifies chronic lymphocytic leukemia/small lymphocytic lymphoma in small B-cell lymphomas

Lymphoid-enhancer-binding factor 1 (LEF1), coupling with β-catenin, functions as a key nuclear mediator of WNT/β-catenin signaling, which regulates cell proliferation and survival. LEF1 has an important role in lymphopoiesis, and is normally expressed in T and pro-B cells but not mature B cells. However, gene expression profiling demonstrates overexpression of LEF1 in chronic lymphocytic leukemia, and knockdown of LEF1 decreases the survival of the leukemic cells. So far, the data on LEF1 expression in B-cell lymphomas are limited. This study represents the first attempt to assess LEF1 by immunohistochemistry in a large series (290 cases) of B-cell lymphomas. Strong nuclear staining of LEF1 was observed in virtually all neoplastic cells in 92 of 92 (100%) chronic lymphocytic leukemia/small lymphocytic lymphomas including two CD5- cases, with strongest staining in cells with Richter's transformation. LEF1 also highlighted the morphologically inconspicuous small lymphocytic lymphoma component in three composite lymphomas. All 53 mantle cell lymphomas, 31 low-grade follicular lymphomas and 31 marginal zone lymphomas, including 3 CD5+ cases, were negative. In 12 grade 3 follicular lymphomas, LEF1 was positive in a small subset (5-15%) of cells. Diffuse large B-cell lymphoma, however, demonstrated significant variability in LEF1 expression with overall positivity in 27 of 71 (38%) cases. Our results demonstrate that nuclear overexpression of LEF1 is highly associated with chronic lymphocytic leukemia/small lymphocytic lymphoma, and may serve as a convenient marker for differential diagnosis of small B-cell lymphomas. The expression of β-catenin, the coactivator of LEF1 in WNT signaling, was examined in 50 chronic lymphocytic leukemia/small lymphocytic lymphomas, of which 44 (88%) showed negative nuclear staining. The findings of universal nuclear overexpression of LEF1 but lack of nuclear β-catenin in the majority of chronic lymphocytic leukemia/small lymphocytic lymphoma suggest that the pro-survival function of LEF1 in this disease may be independent of WNT/β-catenin signaling.

Discordant lymphoma consisting of splenic mantle cell lymphoma and marginal zone lymphoma involving the bone marrow and peripheral blood: a case report

Introduction

Discordant lymphomas are rare entities characterized by the simultaneous presence of two distinct types of lymphomas in different anatomic sites. We describe a very rare case of simultaneous occurrence of splenic mantle cell lymphoma and marginal zone lymphoma involving the bone marrow and peripheral blood.

Case presentation

We report the case of a 60-year-old asymptomatic Caucasian woman in whom discordant lymphomas were discovered when a slight lymphocytosis and a conspicuous splenomegaly were observed. The different morphological, immunophenotypical and immunohistochemical features found in the different pathologic samples obtained from peripheral blood, bone marrow and spleen sections made it possible to differentiate two types of non-Hodgkin B-cell lymphomas: a mantle cell lymphoma infiltrating the spleen and a marginal zone lymphoma involving both the bone marrow and peripheral blood. Since a similar IgH gene rearrangement was found both in the bone marrow and in the spleen, the hypothesis of a common origin, followed by a different clonal selection of the neoplastic lymphocytes may be taken into consideration.

Conclusion

Our case emphasizes the usefulness of investigating simultaneous specimens from different anatomic sites from the same patient and the relevant diagnostic role of splenectomy.