Diagnosis Of Splenic Marginal Zone Lymphoma Research Articles

Deletion 7q Is Associated with KLF2 and NOTCH2 Mutations and Is Strongly Correlated with Splenic Marginal Zone Lymphoma but Also Found in Lymphoplasmacytic Lymphoma and Hairy Cell Leukemia Variant

Introduction: Deletion 7q (del(7q)) isa common cytogenetic aberration in lymphoma and has been associated with splenic marginal zone lymphoma (SMZL). Del(7q) has been proposed to distinguish SMZL from other forms of MZL, i.e. MALT lymphoma and nodal MZL. However, the value of del(7q) in the differential diagnosis of other lymphoid malignancies has not been elucidated. Furthermore, the overall increasing diagnostic and prognostic importance of somatic mutations in hematologic malignancies prompted us to analyze the mutational landscape in lymphomas with del(7q).Aims: To understand the role of del(7q) in lymphoma diagnosis, to define the minimal deleted region in del(7q) bearing lymphomas and to analyze co-occurring cytogenetic aberrations and co-mutations.Patients and Methods: From 2005 to 2017 a total of 5251 patients were diagnosed with lymphoma at our institution by flow cytometry, chromosome banding analysis (CBA) and FISH (2547 (48%) in bone marrow, 2704 (52%) in peripheral blood). Subject of the present study were 3917 patients who were selected based on an aberrant karyotype by (CBA) in order to exclude inclusion of false negative CBA due to limited lymphoma infiltration. To evaluate del(7q) as biological relevant primary hit, del(7q) had to be part of the major clone without a complex karyotype (≥3 abnormalities). 109/3917 patients met this criterion. CD5 negative lymphomas were diagnosed by flow cytometry according to the respective suggestive phenotype as SMZL or lymphoplasmacytic lymphoma (LPL). For 37/109 patients (34%) that had ≥ 20% of lymphoma infiltration by flow cytometry the diagnostic sample was available for array comparative genomic hybridization (aCGH). For 44/109 patients (40%) that had ≥10% infiltration by flow cytometry the diagnostic sample was available for sequencing of 63 genes frequently mutated in hematologic malignancies.Results: We found 109/3917 patients with a del(7q) by CBA (3%). Lymphoma diagnosis with del(7q) included the following eight entities as defined by flow cytometry at decreasing frequency: SMZL (59%), LPL (21%), B-cell prolymphocytic leukemia (6%), hairy cell leukemia variant (HCLv, 6%), chronic lymphocytic leukemia (CLL, 4%), mantle cell lymphoma (2%), aggressive lymphoma (2%), and follicular lymphoma (0.9%). The presence of del(7q) was significantly associated with SMZL, LPL and HCLv (each p<0.0001). Del(7q) was negatively correlated with CLL (p<0.0001). Recurrent cytogenetic aberrations that co-occurred with del(7q) include del(11q), trisomy 3 and dup(1q) in 9%, 3% and 2%, respectively.We analyzed 37/109 patients with aCGH and defined a minimal deleted region of 1.9 MB (Chr7; 128.973.948-130.908.181). Deleted genes in this region include KLF14 (kruppel-like factor 14) and a microRNA (MIR) cluster associated with tumor suppression (MIR182-96-183, MIR 29A, MIR96). The deletion was not entity specific, but 2/5 CLL samples showed a deletion outside the common region of the other lymphomas (7q35-q36.3 and 7q11.21-q21.2).In 44/109 patients the diagnostic sample was analyzed by gene panel sequencing (63 genes) to identify the mutational landscape of del(7q) lymphoma. We identified a total of 53 mutations in 19 different genes in 29/44 patients (66%). The top 10 mutated genes were: KLF2 (27%), NOTCH2 (23%), CXCR4 (9%), MYD88 (9%), NOTCH1 (7%), BIRC3 (7%), MAP2K1 (5%), NRAS (5%), TET2 (5%) and TP53 (5%). Co-occurring mutations in KLF2 and NOTCH2 were observed in 4/44 patients (9%).Somatic mutations in NOTCH2 (10/10) and/or KLF2 (12/12) were exclusively observed in SMZL, and MYD88 (4/4) mutations exclusively in LPL as described in the literature (Fig.). The presence of del(7q) and a mutation in KLF2 and/or NOTCH2 was highly predictive for the diagnosis of SMZL (p<0.0001). Moreover in the presence of del(7q) 18/44 analyzed patients (41%) had NOTCH2 or KLF2 mutations compared to 8% in the control cohort (p<0.0001).Conclusion: Our analysis shows that del(7q) is not restricted to SMZL and is in fact associated also with LPL and HCLv. There is a small common deleted region spanning 1.9 MB at 7q31.32q32.3 which is not entity specific and includes a MIR cluster associated with tumor suppression. Mutations in KLF2 and NOTCH2 were found to be associated with del(7q), which raises the possibility of a common mechanism that remains to be elucidated. Taken together del(7q) combined with somatic mutations in KLF2 and/or NOTCH2 is highly specific for SMZL. [Display omitted] DisclosuresHöllein:MLL Munich Leukemia Laboratory: Employment. Stengel:MLL Munich Leukemia Laboratory: Employment. Meggendorfer:MLL Munich Leukemia Laboratory: Employment. Fasan:MLL Munich Leukemia Laboratory: Employment. Kern:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership.

Superior outcome for splenectomised patients in a population-based study of splenic marginal zone lymphoma in Sweden.

Splenic marginal zone lymphoma (SMZL) is a rare low-grade B-cell lymphoma where associations with viral hepatitis and autoimmune and inflammatory diseases (AID) have been indicated. We aimed at assessing the prevalence of viral hepatitis and AID at SMZL diagnosis and outcome by treatment in a Swedish population-based study. A total of 277 SMZL patients registered in the Swedish Lymphoma Register in 2007-2017 were included. A history of viral hepatitis was reported in five (2%) patients and AID prior to SMZL in 72/240 (30%) patients. Treatment was given up front for 207 (75%) patients. Splenectomy with or without systemic treatment was performed in 119 (57%) and was associated with statistically significantly better overall survival [hazard ratio, HR=0·47 (95% confidence interval, CI: 0·23-0·93), P=0·03] and progression-free survival (HR=0·55, 95% CI: 0·35-0·86, P=0·008) compared to non-splenectomised patients in multivariable analyses. The up-front splenectomised group was younger and generally had a lower Ann Arbor stage, but also more frequently B symptoms and high lactate dehydrogenase than the non-splenectomised group. Viral hepatitis and AID history did not affect SMZL outcome. We report high incidence of AIDs and low incidence of viral hepatitis in this population-based study of SMZL. Splenectomy up front was associated with a favourable outcome.

Ofatumumab Is Active and Safe in Patients with Relapsed/Refractory Splenic Marginal Zone Lymphoma (SMZL): Results from the Interim Analysis of an Italian Multicenter Phase 2 Study (MORE trial)

INTRODUCTIONSplenic marginal-zone lymphoma (SMZL) is a rare disease for which treatment strategies are poorly defined due to the lack of prospective clinical trials and mostly rely on expert opinions. Results from single-center cohorts suggest that rituximab, the most widely available anti-CD20 monoclonal antibody (MoAb), can achieve long-term control of the disease without any need of combining chemotherapy. Ofatumumab is a fully humanised anti-CD20 MoAb and displays a favorable safety profile with lower incidence and milder infusion-related reactions (IRRs) when compared to rituximab. Given the significant efficacy observed in other relapsed/refractory (R/R) indolent lymphomas, we designed a multicenter phase 2 study in Italy to evaluate the activity and safety of ofatumumab monotherapy in patients with R/R SMZL, even after prior treatment with rituximab. Herein, we report preliminary results of a per-protocol interim analysis of the trial. METHODSKey eligibility criteria include: SMZL diagnosis; relapse after or refractoriness to at least one but no more than two lines of treatment; progressive disease requiring treatment due to splenomegaly, bulky lymph nodes and/or cytopenias. Patients might have received previous anti-CD20 MoAb; splenectomy and antiviral treatment (if HBV and/or HCV positive) were not considered in the previous treatment count. Ofatumumab was administered weekly for 8 weeks (1st dose: 300 mg; 2nd-8th dose: 1000 mg). The primary endpoint of the study was the complete remission (CR) rate and sample size should include 43 subjects, with an interim analysis planned on the first 15 patients. RESULTSAs of July 11th, 2018, 20 patients were enrolled at 5 Italian Centers and received at least one dose of study drug. Median age was 73.5 years (55-91), 10 were males. Sixteen patients (80%) have previously received rituximab treatment, in most cases in combination with chemotherapy (considering both first and second-line treatment, 4 BR, 5 R-CHOP, 3 R-CVP, 1 R-cladribine, 1 R-cyclophosphamide and 5 Rituximab monotherapy), with 3 rituximab-refractory and 2 splenectomized patients. These 20 patients were evaluated for safety, while 17 patients receiving the full treatment were assessable for activity according to the protocol. No patients experienced dose delays and/or dose reductions, only one patient discontinued treatment after 2 doses of study drug because of IRRs. Eighteen out of 20 patients experienced at least 1 adverse event (AE). The most frequent AEs of any grade are reported in Table 1. No grade 5 AEs were reported in the trial; 17 grade 3-4 AEs occurred including mainly neutropenia (7 events), thrombocytopenia (5 events, 4 grade 3-4) and IRRs (5 events, only 1 grade 3-4). Five SAEs occurred in 3 patients: hypersensitivity reactions (2 events, both related to the study drug), dyspnea (1, unrelated), pleural effusion (1, unrelated), chest pain occurring during the infusion (1, related).The overall response rate (ORR) in the 17 evaluable patients was 94% (16/17), with 9 (53%) CRs and 7 (41%) partial responses (PRs); importantly, the 3 rituximab-refractory patients achieved a response on ofatumumab (2 CR, 1 PR) (Figure 1). After a median follow-up of 20 months (8-33), 15 patients remain progression-free and 18 patients are still alive. Two patients (the only non-responsive case and the patient who prematurely withdrew from treatment after 2 doses because of IRRs) died because of disease progression at 9 and 20 months; both never received further treatment. The 1-year progression-free survival and overall survival were 86.7% and 100%, respectively. CONCLUSIONOfatumumab was active and safe in these elderly chemoimmunotherapy-treated patients with SMZL. IRRs were generally mild and easily manageable, even in a cohort of patients with a very high median age and a relevant comorbidity burden. The ORR and the CR rate compare favorably with data reported in the literature with rituximab monotherapy also considering that >75% of patients have been previously exposed to rituximab. Ofatumumab deserves to be further investigated to better understand its potential role in this setting. [Display omitted] DisclosuresGhia:Gilead: Honoraria, Research Funding; AbbVie, Inc: Honoraria, Research Funding; Acerta: Honoraria, Research Funding; BeiGene: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Sunesis: Honoraria, Research Funding; Janssen: Honoraria, Research Funding.

Molecular Subtypes of Splenic Marginal Zone Lymphoma (SMZL) Are Associated with Distinct Pathogenic Mechanisms and Outcomes - Interim Analysis of the IELSG46 Study

Molecular Subtypes of Splenic Marginal Zone Lymphoma (SMZL) Are Associated with Distinct Pathogenic Mechanisms and Outcomes - Interim Analysis of the IELSG46 Study

Splenic Marginal Zone Lymphoma in an East Mediterranean/Middle Eastern Population Cohort: Possible Association with Hepatitis B Instead of Hepatitis C Virus As an Etiologic and Prognostic Factor (ThREG-NHL01 Study)

Splenic marginal zone lymphoma (SMZL) is a rare disease. It constitutes less than 2% of lymphoid neoplasms. Chronic antigenic stimulation is frequently blamed in the pathogenesis of extranodal marginal zone lymphomas including SMZL. Chronic hepatitis C is frequently observed in SMZL patients. However these reports are largely from North America and Europe. Data from various countries with different hepatitis prevalence are lacking.In this multicenter cohort study we aimed to find out clinical characteristics of SMZL patients in Turkey including viral hepatitis status and treatment details. Data were gathered from voluntary centers under auspices of Hematolojik Onkoloji Dernegi using a SPSS database. Categorical and continuous data were expressed as ratio (%) and median (range) and they were compared by the Chi-square and Mann Whitney U tests, respectively. Survival analyses were computed by the Kaplan-Meier method. Overall survival (OS) was calculated from diagnosis to the date of mortality of any reason. Patients who did not die at last follow-up were censored at this time for OS computations. Parameters related to survival were investigated by Cox regression univariate and multivariate analyses.66 patients were reported from 8 tertiary care hematology/oncology centers. The diagnosis of SMZL was established by local hematopathologists. Data on baseline clinical characteristics are presented in table 1. Median follow-up duration was 20.4 months (0.3-208) (23 months for surviving patients). 13 patients died during follow-up. Median OS was not reached. Estimated 6 year survival was 59.5% (Figure 1). Older age, no splenectomy during follow-up, <90 x 103 platelet count, lower albumin, higher lactate dehydrogenase, higher b2-microglobulin and HBsAg positivity were associated with increased risk of death. Age, albumin and HBsAg positivity remained significant in multivariate analysis (table 2).HCV positivity was not observed in any patient in this East Mediterranean/Middle Eastern cohort. However 12.1% HBsAg and 32% HBsAg and/or anti-HBcAg positivities are higher than expected for our population. This finding should be confirmed in a larger cohort. Risk factors associated with worse prognosis were generally similar to those reported in European/North American populations. However, HBsAg positivity has not been reported as a risk factor previously. [Display omitted] [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

A Novel Hierarchical Prognostic Model Based on Clinical Feature and Cytogenetics for Splenic Marginal Zone Lymphoma

Background: Splenic marginal zone lymphoma (SMZL) is a rare indolent B-cell neoplasm, which often involved with spleen, bone marrow (BM), and sometimes involved with the peripheral blood. However, the clinical characteristics of Chinese SMZL patients remain elusive.. This present study is undertaken to systematically analyze the clinical and biological characteristics of SMZL in Chinese patients, and draw out an appropriate hierarchical prognostic model of SMZL in the rituximab era.Method: A total of 172 patients with newly diagnosed SMZL in Institute of hematology and blood disease hospital were retrospectively analyzed. Clinical characteristics, including flow cytometry analysis of tumor cells, immunohistochemistry, cytogenetics and molecular detection data were collected and IgHV mutation status, fluorescence in situ hybridization (FISH) data were carried out on patients with available samples.Result: The median age at diagnosis of 172 patients with SMZL was 57 years (range 25-81) and male having little prominence (52.3%). Using a homology cut-off value of 98% to the nearest germline gene, we observed mutated IGHV in 29 (74.4%) and unmutated IGHV in 10 (25.6%) of the 39 SMZL patients. The most frequently used fragments of IGHV gene were IGHV1-2 (25.6%), IGHV4-34 (15.4%), IGHV2-27 and IGHV3-30 (10.3% and 7.8% respectively). The 49.0% patients had HBV infection currently or before SMZL diagnosis, and 14.6% with active HBV infection. Chromosomal aberration was noted in 21.2% patients and 14.4% patients have complex karyotype (more than three aberrations). The FISH detection indicated that the cytogenetic aberrant of 13q- (Rb1/ D13S25), trisomy 12, 17p-(TP53) and t(14q32) was 9.8% (8/82), 9.6% (8/83), 4.7% (6/126) and 20.4% (19/93), respectively. Among those patients, 64 patients (41.6%) received rituximab-based immunochemotherapy as the first line treatment and other 37 patients (24.0%) with conventional chemotherapy treatment alone.With a median follow-up of 50.5 months (range, 6-214 months), the estimated 5-year failure-free survival (FFS) and overall survival (OS) rates were 74.6% and 80.8%, respectively. The 5-year FFS for patients with rituximab-based treatment was significantly prolonged than those rituximab-free treatment patients (89.9% vs 60.9%, P = 0.005). Based on the univariate analysis, the significant predictive parameters for shorter OS included hemoglobin level <11 g/dl (p=0.000), HBVs-Ag positivity (p=0.001), FLIPI 4-5 (p=0.000), trisomy 12 (p=0.004), chromosomal aberration (p=0.007), complex karyotype (p=0.001) and ECOG 2-4 (p=0.005). A Cox regression model of OS revealed that hemoglobin level <11 g/dl, HBV-Ag positivity, complex karyotype were the independent prognostic factors (p=0.045, 0.044 and 0.002, respectively). Of note, only HBVs-Ag positivity and complex karyotype aberrant had a negative influence on OS even after adjusted by rituximab treatment.Using above 3 independent variables, we identified a novel hierarchical prognostic model with three risk groups: low-risk group (39.2%) with no adverse factors, intermediate-risk group (38.6%) with one factor and high-risk group (22.1%) with 2 or 3 factors. The 5-year OS was 96.7%, 78% and 53.3%, respectively (p=0.000). The 5-year FFS was 95%, 67.5% and 39.4%, respectively (p=0.000). The novel hierarchical prognostic model showed an advanced c-index than the other risk models, including IPI, FLIPI and the tradition SMZL score significantly.Conclusion: Chinese patients with SMZL have distinct clinical characteristics. The novel prognostic index system composed of hemoglobin, HBVs-Ag and complex karyotype aberrant could effectively stratify the outcomes of patients with SMZL and appears to be a promising risk model for Chinese SMZL patients in the rituximab era. DisclosuresNo relevant conflicts of interest to declare.

Identification of splenic marginal zone lymphoma from B lymphoproliferative disorders by flow cytometry

The splenic marginal zone lymphoma (SMZL) is a relatively rare chronic B lymphoproliferative disease, which primarily manifest increase of peripheral blood lymphocyte count and/or scale, and splenomegaly, while the peripheral superficial lymph nodes are often not swollen. Therefore, the splenectomy are usually needed to confirm the diagnosis, but the majority of patients could not accept such management, resulting in early difficult diagnosis. This study was purposed to explore the more prior way for diagnosis based flow cytometry (FCM). Six patients with suspected diagnosis of SMZL were used as research objects, 10 healthy bone marrow donors and 10 cases of chronic lymphocytic leukemia (CLL), 3 cases of hairy cell leukemia (HCL), 3 cases of lymphatic plasma cell lymphoma/Waldenströ's macroglobulinemia (LPL/WM) were selected as control. The immunophenotype of bone marrow cells were analyzed and compared by FCM using a panel of antibodies including CD45, CD5, CD10, CD19, CD20, CD22, CD23, CD25, CD103, CD11c, CD123, κ,λ, Cyclin D1, and combined with bone marrow cell morphology. The results indicated that 6 cases of suspected SMZL showed a large increase of lymphocytes and splenomegaly. Because absence of peripheral lymphadenopathy, 6 patients did not suffer from lymph node biopsy, only 1 patient underwent diagnostic splenectomy. The immunophenotypes of bone marrow in patients and controls were analyzed by FCM, as a result, except for the healthy donors, varying degrees of abnormal mature B cell clones were found in bone marrow of all patients, and the further differentiation from other B-cell tumors was performed through CD5, CD10 expression and combination with other B-cell phenotype. All 6 cases of SMZL patients expressed CD19(+) and CD20(+), but CD10 expression was negative, 4 patients expressed CD5(-), 2 patients expressed CD5(+). The expressions of CD23, CD38, ZAP-70, CD11c, CD103, CD123, Cyclin D1 were negative. The morphological examination of bone marrow cells showed velutinous abnormal lymphocytes. Combined with clinical characteristics, 6 patients were diagnosed as SMZL, 1 patient suffered from splenectomy because of concurrent hypersplenism, and this postoperative pathologic examination confirmed the patient with SMZL. Ten cases of CLL mainly expressed CD5, CD23; 3 cases of HCL had more typical morphology of "hair like" in addition to CD11c, CD103 and CD123 positive; 3 cases of LPL/WM had significantly increased light chain restriction expression, IgM, plasmacytoid lymphocytes. It is concluded that the FCM immunophenotype analysis can be used as a powerful tools for clinical diagnosis of SMZL.

Bone Marrow Histopathology in the Diagnostic Evaluation of Splenic Marginal-zone and Splenic Diffuse Red Pulp Small B-cell Lymphoma

Primary splenic small B-cell lymphomas mostly comprise the distinct entity of splenic marginal-zone lymphoma (SMZL) and the provisional category of splenic lymphoma/leukemia unclassifiable, mainly represented by the hairy cell leukemia variant and splenic diffuse red pulp small B-cell lymphoma (SDRL). Until recently, histopathologic examination of splenectomy specimens was considered mandatory for the diagnosis of SMZL. However, nowadays, mainly because of advances in chemoimmunotherapy, splenectomy is performed much less frequently. We evaluated the diagnostic efficacy of bone marrow biopsy (BMB) histopathology in the diagnostic approach toward SMZL and SDRL and tested whether it may serve as a substitute for spleen histopathology in the differential diagnosis between these 2 entities. To this end, we conducted a paired assessment of BMB and spleen diagnostic samples from 46 cases with a diagnosis of SMZL (n=32) or SDRL (n=14) based on spleen histopathology. We demonstrate that detailed immunohistopathologic BMB evaluation offers adequate evidence for the confirmation of these entities and their differential diagnosis from other small B-cell lymphoma histotypes. Notably, the immunophenotypical profile of SMZL and SDRL was identical in both BMB and spleen specimens for 21 evaluated markers. Paired assessment of BMB and spleen specimens did not identify discriminating patterns of BMB infiltration, cytology, and/or immunohistology between SMZL and SDRL. Accordingly, bone marrow histopathology contributes significantly in confirming the diagnosis of SMZL and SDRL. However, presently it is not possible to distinguish SMZL from SDRL on the basis of BMB evaluation alone; hence, histopathologic examination of the spleen remains the "gold standard" approach.

Over 30% of Patients with Splenic Marginal Zone Lymphoma Express Distinctive Antigen Receptors Utilizing a Single Immunoglogulin Variable Gene: Implications for the Origin and Selection of the Neoplastic Cells

AbstractAbstract 634We systematically explored the immunoglobulin (IG) gene repertoire in 337 cases with splenic marginal-zone lymphoma (SMZL), by far the largest series yet. To resolve classification uncertainties, we included in the analysis only cases with a diagnosis of SMZL based on spleen histopathological findings or cases fulfilling the 2008 SBLG criteria (Matutes et al. Leukemia 2008). We here report that the IG heavy variable (IGHV) gene repertoire in SMZL is remarkably biased, with only three genes accounting for 45.8% of cases (IGHV1-2, 24.9%; IGHV4-34, 12.8%; IGHV3-23: 8.1%, respectively), significantly extending previous similar observations. Particularly for the IGHV1-2 gene, strong biases became evident at the level of utilization of different alleles, since 79/86 rearrangements (92%) utilized allele *04 vs. only 7/86 rearrangements (8%) that utilized allele *02. This is noteworthy, taking into consideration that these two alleles differ in a single nucleotide, leading to a single amino acid change in framework region (FR)-3. The repertoire biases became more pronounced when the analysis was focused on 171 rearrangements from 163 cases classified as SMZL based on splenic histopathology, according to the 2008 WHO criteria. Within this subgroup, 56/171 cases (32.7%) utilized IGHV1-2*04. Noticeably, only 1/17 cases with a diagnosis of splenic diffuse red pulp lymphoma utilized IGHV1-2*04 (p<0.02 for comparison to SMZL). The IGHV1-2*04 rearrangements carried significantly longer heavy complementarity-determining region-3 (VH CDR3) than all other cases (median, 22 vs. 17 amino acids, respectively; p<0.001). In addition, 52/79 IGHV1-2*04 cases (65.8%) employed one of the IGHD3-3, IGHD3-9 or IGHD3-10 genes. In 28/32 IGHV1-2*04/IGHD3 rearrangements, the IGHD gene was utilized in the same reading frame, leading to VH CDR3s with common “IGHD-derived” amino acid (AA) motifs. Using bioinformatics tools previously applied to CLL, biased associations of IGHV, IGHD and IGHJ genes with stereotyped VH CDR3s were identified in 25/345 sequences (7.2%). Noticeably, only 10/28 IGHV1-2*04/IGHD3-3 rearrangements with “IGHD-derived” VH CDR3 amino acid motifs could be assigned to “stereotyped” clusters. Despite exhibiting restricted usage of the IGHV1-2*04 and IGHD3-3 genes leading to great overall VH domain similarity, the remaining cases did not fulfill the established criteria for VH CDR3 “stereotypy”, as defined in other lymphoid malignancies, namely CLL. Based on somatic hypermutation (SHM) analysis, the sequences were divided into three groups: (i) truly unmutated (100% germline identity, GI): 46/345 sequences (13.3%); (ii) minimally/borderline mutated (97-99.9% GI): 130/345 sequences (37.7%); and (iii) significantly mutated (<97% identity): 169/345 sequences (49%). At the individual gene level, the distribution of rearrangements of IGHV genes according to SHM status varied significantly. In particular, 56/79 IGHV1-2*04 rearrangements (71%) were predominantly “borderline mutated”, whereas the majority (>67%) of rearrangements utilizing the IGHV3-23, IGHV3-30 and IGHV3-7 genes were “significantly mutated”; finally, IGHV4-34 gene rearrangements were evenly distributed to the three mutational subgroups. Shared (“stereotyped”) AA changes were identified for IGHV1-2*04 rearrangements, with certain FR2 and FR3 codons emerging as “hotspots” for recurrent, conservative AA changes. In conclusion, we demonstrate that more than 30% of cases with a histopathological diagnosis of SMZL on the spleen express IGHV1-2*04 receptors with unusually long VH CDR3s, biased usage of the IGHD3-3 gene, leading to shared “IGHD-derived” VH CDR3 motifs, and very precise molecular features of SHM. The biased expression of a distinctive germline-encoded VH specificity might be considered as evidence for heavy chain dominance in the clonogenic IG receptors in SMZL. These findings allude to selection by specific (super)antigenic element(s) in the pathogenesis of at least a major subset of SMZL. In addition, they raise the intriguing possibility that certain subtypes of SMZL could derive from progenitor cell populations adapted to particular antigenic challenges through cellular selection of VH domain specificities. Disclosures:No relevant conflicts of interest to declare.

Histopathological EXAMINATION of BONE MARROW Biopsy (BMB) IN Primary Splenic B CELL Lymphomas of Marginal-ZONE ORIGIN (PSMZL). A Reliable Substitute for Spleen Pathology?.

Abstract 1924Poster Board I-947According to the 2008 WHO Classification, PSMZLs mainly comprise splenic marginal-zone lymphoma (SMZL) and splenic diffuse B cell lymphoma/leukemia unclassifiable (SDLU). Until recently, histological examination of splenectomy specimens was considered as a prerequisite for the diagnosis of SMZL though, due to the recent advancement in chemo-immunotherapy therapies, splenectomy is no longer performed in most cases. We evaluated the diagnostic efficiency of BMB examination in the documentation of the diagnosis of PSMZLs and their differential diagnosis from mimickers, including other small B-cell lymphomas, and tested whether BMB may serve as a substitute for spleen microscopic examination in the differential diagnosis of SMZL from SDLU. The study group included 108 BMB samples from patients with a diagnosis of PSMZL based either on examination of splenectomy specimens (n= 46), or clinical presentation, cell morphology and flow cytometry analysis (n= 62). Histological and immunohistochemical results are summarized in Table 1. Molecular analysis of immunoglobulin genes showed that 10/21 analyzed CD27+ cases carried IGHV genes with more than 98% germline identity (unmutated), whereas 5/8 analyzed CD27- cases carried mutated IGHV genes. Furthermore, 7/14 analyzed SIgD+ cases carried mutated IGHV genes. Splenectomy specimens were available in 46/108 cases. Blinded histopathological examination of the spleens revealed 35 SMZL and 11 SDLU. Paired assessment of BMB and spleen specimens did not identify any discriminating pattern of BM infiltration and/or morphology between SMZL and SDLU; notably, the immunophenotypical profile of BMB and spleen specimens was identical when 14 different markers have been utilized (Table 1). In conclusion, our study documents the value of BMB histopathology in the diagnosis of PSMZLs and their differential diagnosis from other small B-cell lymphomas primarily or secondarily involving the spleen. Presently, it is not possible to distinguish SMZL from SDLU based on the only BMB histopathology. Finally, our results confirm and expand the considerable heterogeneity of PSMZL, which could reflect different activation status and/or different histogenesis of the clonogenic cells.Table 1Histology and immunohistochemistry.Pattern of infiltrationPure intrasinusoidal6/108Interstitial19/108Nodular4/108Diffuse8/108Mixed intrasinusoidal-interstitial39/108Nodular combined with other types32/108MorphologySmall lymphocytes105/108plasmacytic differentiation (PC)13/105onocytoid differentiation (MC)20/105Pure MC population3/108ImmunohistochemistryCD20+ CD79á+BCL2+108/108CD43+BCL6+CD10+CyclinD1+0/108CD5+7/98CD23+4//91CD5+CD23+0/91TRAP+31/58DBA44+59/93CD27+44/70SIgD+30/61SIgD+CD27+18/24 Disclosures:No relevant conflicts of interest to declare.

Transformation of Indolent Small B-Cell Lymphoma to Histiocytic Sarcoma: Report of Two Cases with Molecular/Genetic Evidence of Clonal Relationship Between Two Morphologically and Immunophenotypically Distinctive Neoplasms.

Abstract 3960Poster Board III-896 IntroductionRare cases of histiocytic sarcoma (HS) have been reported in association with indolent small B-cell neoplasms, either concurring with or following a small B-cell lymphoma. The biologic relationship between these two morphologically and immunophenotypically distinct neoplasms in same patients remains unclear, though recent data suggest a possible “transdifferentiation” from follicular lymphoma (FL) to HS. Patients and MethodsWe investigate the clonal relationship in two cases of B-cell lymphoma with subsequent HS, using immunohistochemical stains, PCR-based immunoglobulin heavy chain (IGH) gene rearrangement/sequencing analysis and interphase FISH study on formalin fixed, paraffin-imbedded tissue sections. ResultsCase 1 is a 62-year-old female with splenic marginal zone lymphoma (SMZL) who developed HS in a groin lymph node one year after the diagnosis of SMZL. PCR/sequence analysis of IGH gene showed a monoclonal rearrangement carrying identical DNA sequences of PCR products from the spleen with SMZL and the lymph node with HS. Case 2 is a 61-year-old female with a remote history of FL who developed supraclavicular lymphadenopathy and multiple other infiltrating foci. A supraclavicular lymph node biopsy demonstrated HS. PCR analysis detected a monoclonal rearrangement of the IGH gene and interphase FISH analysis revealed IGH/BCL-2 fusion, a genetic hallmark for FL. Although negative for other B-cell associated antigen markers, HSs show partial retention of primary neoplasms B-cell lymphomas' immunoprofiles, including expression of Oct-2 in both cases, and expression of bcl-6 and enhanced expression of bcl-2 in case 2. ConclusionThe data provide a genotypic evidence of common clonal origin between mature B-cell lymphoma and subsequent HS in the same patients, suggesting “transdifferentiation” to HS could occur in other small B-cell lymphoma, in addition to FL. The transformed HSs might have incompletely inherited primary neoplasms' expression signatures by retaining B-cell lymphomas' characteristic immunoprofile to certain extent. The exact mechanism governing the conversion of mature B-cell lymphoma to HS is largely a mystery and remains to be elucidated by more scientific studies, though a few pathways have been proposed for the process, including transdifferentiation, dedifferentiation and common progenitor models.TableAnalysis of Two Cases of Histiocytic Sarcoma Arising in Small B-cell LymphomaCase 1Case 2Primary neoplasmSMZLFLInterval between 1st and 2nd neoplasm (yrs)117--Immunohistochemical and other studiesLeukocyte common antigenCD45W+W+B-cell antigensCD20--CD79a--Pax-5--OCT-2W/M+W+BOB-1--T-cell antigensCD2--CD3--CD5--CD4W+W+CD8--Follicle center antigensCD10--Bcl-6-W/M+Histiocytic/dendritic cell antigensCD68++CD163++CD1a--CD21--CD23--CD35-ndS100F+F+LysozymeF+F+OthersMPO--Bcl-2-/W+Br+Ki-6720-30%15-25%EBER ISH--Genetic studiesIGH gene rearrangementClonalClonalFISH for IGH/BCL-2-+SMZL, splenic marginal zone lymphoma; FL, follicular lymphoma; +, positive; W+, weakly positive; W/M+, weakly to moderately positive; F+, focally positive; Br+, brightly positive; -, negative; nd, not done Disclosures:No relevant conflicts of interest to declare.

Splenic marginal zone lymphoma proposals for a revision of diagnostic, staging and therapeutic criteria

Since the initial description of splenic marginal zone lymphoma (SMZL) in 1992, an increasing number of publications have dealt with multiple aspects of SMZL diagnosis, molecular pathogenesis and treatment. This process has identified multiple inconsistencies in the diagnostic criteria and lack of clear guidelines for the staging and treatment. The authors of this review have held several meetings and exchanged series of cases with the objective of agreeing on the main diagnostic, staging and therapeutic guidelines for patients with this condition. Specific working groups were created for diagnostic criteria, immunophenotype, staging and treatment. As results of this work, guidelines are proposed for diagnosis, differential diagnosis, staging, prognostic factors, treatment and response criteria. The guidelines proposed here are intended to contribute to the standardization of the diagnosis and treatment of these patients, and should facilitate the future development of clinical trials that could define more precisely predictive markers for histological progression or lack of response, and evaluate new drugs or treatments.

Splenectomy for Splenic Marginal B-Cell Lymphoma.

Background: Splenic marginal zone lymphoma (SMZL) is an uncommon indolent B-cell malignancy usually involving the spleen, bone marrow and blood. Splenectomy is frequently performed for both diagnostic and therapeutic purposes, but it is unclear if it affects outcome. To further explore this issue, we reviewed clinical and pathological characteristics, and treatment outcomes of SMZL patients (pts) who underwent splenectomy in our institution.Methods: Medical records of pts who had splenectomy at the Cleveland Clinic and were diagnosed with a B-cell lymphoproliferative disorder between 1994 and 2004 were reviewed. Pathology slides were reviewed to confirm the diagnosis of SMZL by WHO criteria. Data collection included: clinical and biochemical characteristics at diagnosis including symptoms; reason for and date of splenectomy; hematological response following surgery; additional therapies other than surgery including rationale, regimen used and outcome; and follow-up data.Results: We identified 18 pts with SMZL having splenectomy in our institution. Twelve (67%) were females and 6 (33%) males. The median age was 65 years (range 43–85). At the time of diagnosis, 9 pts had splenic and bone marrow involvement; 8 splenic, bone marrow and nodal; 1 spleen involvement only. Four pts were treated with chemotherapy prior to splenectomy for presumed CLL, hairy-cell leukemia or unspecified B-cell lymphoproliferative disorder, but none achieved CR. None of the pts received radiation. Splenectomy was performed in 9 pts for diagnostic, and in 9 pts for therapeutic purposes. The most common reason for therapeutic splenectomy was cytopenia (n=5) and abdominal discomfort (n=4). Median follow-up from splenectomy to death or last follow-up is 30 months (range 1–99). Of the 9 pts who had splenectomy for diagnostic purposes the median time to subsequent systemic therapy (n=5) was 7 months (range 0–33). Of the 9 pts treated for therapeutic purposes abdominal symptoms resolved in all (n=4) and 4/5 with cytopenias achieved hematologic response. Seven of 9 pts with only spleen and marrow involvement, achieved complete hematologic remission following surgery lasting from 8+ to 46+months. Of 8 pts presenting with spleen and lymph node involvement, 6 had cytopenias that resolved in only 3 pts following splenectomy. Six of these 8 pts received chemotherapy after splenectomy with median time from surgery to systemic treatment of 16 months (range 3–60). One pt continues to have stable lymphadenopathy observed clinically for 33 months, and 1 pt had stable lymphadenopathy for 24 months and was subsequently lost to follow-up.Conclusion: Splenectomy, whether performed diagnostically or therapeutically, may result in long remissions in the absence of chemotherapy. Splenectomy appears to be a viable treatment alternative for SMZL.

Meningeal Lymphomatosis as the First Manifestation of Splenic Marginal Zone Lymphoma

Meningeal lymphomatosis (ML) as the first manifestation of a splenic marginal zone lymphoma (SMZL) is rare. The descriptions of only 2 cases with this complication, one of which had ML as the first manifestation, have been published to date. We describe a 53-year-old man, an ex-smoker, who presented with transitory episodes of bilateral loss of visual acuity. On examination, only papilledema and splenomegalia were observed. The hemogram showed a predominance of lymphocytes with a villous morphology. Cytochemical staining and an immunophenotypic analysis revealed a positive reaction to tartrate-sensitive acid phosphatase and B-lineage markers (CD19+, CD20+, CD79b+, surface immunoglobulin 3 expression, immunoglobulin D+, CD5-, CD23-, CD10-, CD25-, CD103-, and CD11c-). Magnetic resonance imaging of the brain showed tumoral infiltration in both optic nerves and in the cervicodorsal meninges. The cerebrospinal fluid examination revealed significant pleocytosis, and all lymphocytes had a phenotype identical to that of the peripheral blood, confirming the presence of ML. The bone marrow section also showed lymphocytes with an immunophenotype identical to that of the peripheral blood.A splenectomy confirmed the SMZL diagnosis. Treatment with corticosteroids and intrathecal chemotherapy was administrated; however, the response was not good, and the patient died. In this report, we discuss the other 2 cases and ML in B-cell chronic lymphoproliferative disorders.

Splenic marginal zone lymphoma with or without villous lymphocytes. Hematologic findings and outcomes in a series of 57 patients.

Splenic marginal zone lymphoma (SMZL) is a well defined pathologic entity. However, questions regarding the bone marrow infiltration rate, the minimal diagnostic data set, and therapy remain unanswered. Clinical-pathologic features and outcomes of 57 consecutive patients who had splenomegaly with no clinically significant lymphadenomegaly and who were diagnosed with SMZL with or without (+/-) villous lymphocytes (VL) were reviewed. SMVL +/- VL occurred mostly in elderly males (median age, 62 years +/- 10 years; male-to-female ratio, (1.85). Anemia was recorded in 49% of patients, and 30% of patients had moderate thrombocytopenia. Leukocytosis and leukopenia were found in 33% and 14% of patients, respectively, and typical VL were found in 84% of patients. Serology for hepatitis C virus infection was positive in 16% of patients, and a small monoclonal component was detected in 36% of patients. The bone marrow was infiltrated with an intrasinusoidal component in all patients. Thirteen patients were monitored using a watch-and-see policy, and they remained alive 1-5 years after diagnosis. Overall, 21 patients (36%) underwent splenectomy; and, in all patients, the diagnosis of SMZL was confirmed histologically in the surgical specimens. Twenty-five patients received single-agent therapy, which included either alkylators or pentostatine, and they achieved an overall response rate (ORR) of 65% and 87%, respectively: Polychemotherapy was administered to 6 patients (ORR, 83%). The median survival for all patients in the series was not reached, and it is expected that 70% of patients will be alive at 5 years. Up to 20% of patients who had SMZL +/- VL could be monitored using a watch-and-wait policy. The bone marrow intrasinusoidal infiltration pattern may be a valuable diagnostic hallmark, thus obviating diagnostic splenectomy. The issues regarding prognostic stratification and the best therapeutic strategy need to be addressed in properly designed, prospective trials.

Progression to large B-cell lymphoma in splenic marginal zone lymphoma: a description of a series of 12 cases.

Splenic marginal zone lymphoma (SMZL) is considered to be an indolent extranodal B-cell lymphoma. Despite its low aggressivity, histologic progression has been described in sporadic reports, although the frequency, characteristics, and underlying molecular abnormalities of this phenomenon are largely unknown. We review here the clinical, morphologic, immunohistochemical, and molecular features of a series of 12 SMZL cases that showed progression to large B-cell lymphoma (LBCL). The most frequent location of secondary LBCL was in peripheral lymph node. This occurred between 12 and 85 months after diagnosis of SMZL. However, in two cases LBCL was diagnosed at the initial stage of the disease (one spleen tumoral nodule and one hilar lymph node). The histologic and immunophenotypic features of these cases were similar to those of transformed LBCL at other sites. In four cases the immunoglobulin heavy chain gene polymerase chain study revealed the same rearrangement pattern in both primary and secondary tumors, thereby confirming their identity and excluding the possibility of a second malignancy. As is the case with other low-grade lymphoproliferative disorders, SMZL may undergo high-grade transformation. These 12 cases represent 13% of our series of SMZL with adequate follow-up. The incidence of large cell transformation in SMZL seems to be lower than in follicular lymphoma (25-60%) and mantle cell lymphoma (11-39%), although it is similar to the frequency of transformation in B-chronic lymphocytic lymphoma/small lymphocytic lymphoma (1-10%). The mean proliferative index (MIB1 staining) in initial SMZL specimens of cases with LBCL transformation was 28.6%, higher than that of MIB1 staining in the overall SMZL series (21.8%), although not statistically significantly so. p53 or p16INK4a inactivation in this series was observed in only one case, in contrast with the situation observed in chronic lymphocytic leukemia, follicular lymphoma, and mantle cell lymphoma. It seems that progression in SMZL is mainly independent of p53 or p16INK4a inactivation. The frequency of the 7q deletion in this series was 3 of 7 (42%). 7q loss may play an alternative role in the inactivation of the p53 and p16INK4a pathway, thereby favoring tumoral progression.

Splenic involvement by blastic mantle cell lymphoma (Large cell/anaplastic variant) mimicking splenic marginal zone lymphoma

The most cases of splenic marginal zone lymphoma (SMZL) seem to respond favorably to splenectomy. The diagnosis of this lymphoma is mainly based on the recognition of a micronodular pattern of splenic involvement with marginal zone differentiation. However, it is possible to find so-called “marginal zone differentiation“ in splenic involvement by other small B-cell lymphomas, particularly mantle cell lymphoma (MCL) and follicular lymphoma. We report a case of blastic MCL, large cell/anaplastic variant with a high level of clinical aggressiveness, showing biphasic cytology and a micronodular pattern which resembles SMZL. A single biopsy corresponding to this case shows two phases of tumoral progression in a MCL, a rare finding in MCL. In conclusion, the differential diagnosis of SMZL must take the possibility of a blastic MCL with biphasic cytology into account, as the case here. Am. J. Hematol. 62:242–246, 1999. © 1999 Wiley-Liss, Inc.

A marginal zone pattern may be found in different varieties of non-Hodgkin's lymphoma: the morphology and immunohistology of splenic involvement by B-cell lymphomas simulating splenic marginal zone lymphoma.

Splenic marginal zone lymphoma (SMZL) is characterized by a micronodular infiltrate of the splenic white pulp, centred on pre-existing follicles, with a peripheral rim of 'marginal' zone B-cells, always accompanied by a variable degree of red pulp infiltration. These histological features can be closely mimicked by a variety of other small B-cell lymphomas when they involve the spleen, which makes recognition of SMZL difficult. We therefore have compared the histopathological and immunohistochemical features of other non-Hodgkin's lymphoma (NHL) types with those of SMZL. We selected cases of splenic involvement by different types of B-cell lymphoma, including mantle cell lymphoma (MCL), follicular lymphoma (FL), immunocytoma (IM) and lymphocytic lymphoma (B-CLL). A micronodular pattern and marginal zone differentiation were both found to be frequently present in FL and MCL, and with lesser frequency in IM and B-CLL. The main morphological feature useful for differential diagnosis was the cytological composition of the white pulp tumoral nodules. SMZL is distinguished by characteristic dimorphic cytology, different from the monomorphic cytology of MCL, and the distinctive mixture of centroblasts and centrocytes which is the rule in FL. B-CLL could also be identified on the basis of the polymorphic cytology including small lymphocytes and prolymphocytes, whereas cases diagnosed as IM show prominent plasmacytic differentiation, lacking the features of the other lymphoma types. Immunohistochemistry was particularly useful for the differential diagnosis. Thus the recognition of MCL was facilitated by the identification of cyclin D1 and CD43 reactivity, while FL could be recognized by the lack of IgD expression or the distinctive pattern of Ki67 staining found in SMZL. B-CLL cells were CD23+, CD43+. The results of this study provide morphological and immunohistological information useful in the recognition of the different varieties of NHLs when involving the spleen and the differential diagnosis of SMZL.