Cells Of Nodular Lymphocyte-predominant Hodgkin Lymphoma Research Articles

MEF2B is the ideal immunohistochemical marker to highlight neoplastic LP cells in nodular lymphocyte-predominant Hodgkin lymphoma.

MEF2B is the ideal immunohistochemical marker to highlight neoplastic LP cells in nodular lymphocyte-predominant Hodgkin lymphoma.

Tumour cell characteristics and microenvironment composition correspond to clinical presentation in newly diagnosed nodular lymphocyte-predominant Hodgkin lymphoma.

Different studies have characterized the microenvironment and its prognostic impact in classic Hodgkin lymphoma whereas such analyses are pending for nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL). We thus investigated characteristics of tumour cells and microenvironment in NLPHL and evaluated possible correlations with the clinical presentation. Lymph node samples from 152 NLPHL patients who had first-line treatment within the randomized German Hodgkin Study Group HD16-HD18 trials were available and analysed with regard to IgD status and nuclear size of the tumour cells as well as presence of PD1-positive follicular T helper cells and CD163-positive macrophages in the microenvironment. While large tumour cell nuclei and high numbers of PD1-positive follicular T helper cells in the microenvironment were more common in patients presenting with early/intermediate stages than in patients with advanced-stage disease (p< 0.0001, unpaired t-test; p= 0.0022, Mann-Whitney test), no differences between risk groups were observed in terms of the IgD status of the tumour cells and the content of CD163-positive macrophages in the microenvironment. PD1-positive follicular T helper cells were present in both cases with typical and variant growth patterns and rosetting around the tumour cells was observed in 96% of patients, indicating an important role of PD1-positive follicular T helper cells in NLPHL.

Nodular Lymphocyte-predominant Hodgkin Lymphoma With Nodular Sclerosis: An Underrecognized Feature Associated With Pattern D.

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) with unusual features, including some that can overlap morphologically with classic Hodgkin lymphoma (CHL), have been described. Herein, we describe 12 cases of NLPHL with fibrous bands and capsular fibrosis resembling, in part, nodular sclerosis (NS) CHL. Seven of 12 cases harbored Reed-Sternberg-like cells, further suggestive of CHL, but all cases lacked associated eosinophils and/or plasma cells in the background. In this cohort, all cases had areas of so-called pattern D (nodular T-cell rich) as a sole component in 7 (58%) cases or as a hybrid pattern along with pattern E (diffuse T-cell/histiocyte-rich) in 5 (42%) cases. The immunophenotype of the large neoplastic cells in these cases supported their being lymphocyte predominant cells of NLPHL, positive for CD20, CD79a, and OCT2, and negative for CD15 and CD30. However, PAX5 was weak in 9 of 11 cases similar to Hodgkin/Reed-Sternberg cells in CHL. We conclude that some cases of NLPHL are associated with fibrous bands and capsular fibrosis and resemble, in part, NS CHL. In our experience, NLPHL with NS-like features occurs in 10% to 15% of cases of NLPHL and is associated with a variant pattern (D and/or E). In addition, all patients in this cohort were not treated before biopsy, suggesting that the prominent sclerosis in these cases is inherent to disease biology. Recognition of NLPHL with NS-like features further expands the morphologic spectrum of NLPHL and helps avoid potential misdiagnosis as CHL.

Nodular Lymphocyte-Predominant Hodgkin Lymphoma: Review of Current Literature and Case Discussion.

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare subset of Hodgkin lymphoma (HL). It has a distinct clinical and pathological presentation. Unlike classic HL, where the predominant malignant cells are Reed Sternberg cells, the malignant cells in NLPHL are known as lymphocyte predominant (LP) cells, with their own unique immunohistochemistry antigen expression and staining pattern. Based on risk stratification and staging of the disease, treatment can range from active surveillance in asymptomatic patients with no organ compromise or bulky disease, to aggressive chemotherapeutic agents in advanced disease. Guidelines on which of these chemotherapy regimens would offer the most benefit to our patients are limited due to lack of randomized-controlled studies. Majority of the current prospective data on treatment were inclusive of both HL and NLPHL. Thus, the regimens employed in treatment of NLPHL are similar to the ones used in HL, though NLPHL is often viewed as its own distinct entity. This article aims to review the current literature and future advances on treatment of this rare disease.

The NLPHL Tumor Microenvironment Is Markedly Enriched in the Tigit and PD-1 Signalling Axes Compared to Classical Hodgkin Lymphoma

The NLPHL Tumor Microenvironment Is Markedly Enriched in the Tigit and PD-1 Signalling Axes Compared to Classical Hodgkin Lymphoma

Treatment of Early-Stage Nodular Lymphocyte-Predominant Hodgkin Lymphoma: A Subgroup Analysis of the Randomized German Hodgkin Study Group HD16 Study

Background:Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare lymphoma entity accounting for approximately 5% of all Hodgkin lymphoma (HL) cases. Pathological and clinical characteristics differ from classical HL (cHL). In contrast to cHL, the malignant cells in NLPHL are consistently positive for CD20 but stain negative for CD30. The clinical course of NLPHL is usually indolent and patients present with early-stage disease more frequently than in cHL.Patients and Methods:We investigated characteristics and outcomes of 85 patients with NLPHL (stage IB and stage II without risk factors) who had treatment within the randomized German Hodgkin Study Group HD16 study for early-stage HL. Results were compared to those from 495 cHL patients (stage IB and stage II without risk factors) treated within the same study. Patients were randomized between standard treatment consisting of 2 cycles of ABVD followed by consolidation radiotherapy and treatment guided by interim positron emission tomography after 2 cycles of ABVD (PET-2). PET-2-guided treatment consisted of 2 cycles of ABVD alone for patients with a negative PET-2 and 2 cycles of ABVD followed by consolidation radiotherapy for patients with a positive PET-2 (defined as a Deauville score ≥ 3). Progression-free survival (PFS) and overall survival (OS) were analyzed using the Kaplan-Meier method including 95%-confidence intervals (95%-CI) and hazard ratios (HR) obtained from Cox regression models. Analyses were performed descriptively.Results:Overall, 62/85 NLPHL patients (73%) were male as compared to 254/495 cHL patients (51%) (p=0.0002). The median age was 37 years (range: 19-71 years) among patients with NLPHL and 36 years (range: 18-75 years) among patients with cHL (p=0.4380). Information on the histopathological growth pattern was available for 67/85 NLPHL patients of which 44 (66%) had a typical growth pattern. The PET-2 was positive in 39/85 NLPHL patients (46%) and in 171/495 cHL patients (35%) (p=0.0507). After a median observation time of 64 months, the 5-year PFS was 90.3% (95%-CI: 83.8-96.7%) for all 85 NLPHL patients and 90.8% (95%-CI: 88.1-93.5%) for all 495 cHL patients (HR=1.1; 95%-CI: 0.5-2.1). The 5-year PFS rates for PET-2-positive NLPHL (n=39) and cHL (n=171) patients were 89.3% (95%-CI: 79.4-99.2%) and 91.6% (95%-CI: 87.2-96%) (HR= 1.3; 95%-CI: 0.5-3.5), respectively. The 5-year PFS rates for PET-2-negative NLPHL (n=46) and cHL (n=324) patients were 91% (95%-CI: 82.7-99.4%) and 90.4% (95%-CI: 87-99.4%) (HR=0.85; 95%-CI: 0.3-2.4), respectively. PET-2-negative NLPHL (n=25) and cHL (n=152) patients treated with 2 cycles of ABVD alone had 5-year PFS rates of 83% (95%-CI: 67.8-98.2%) and 88.2% (95%-CI: 82.7-93.6%) (HR=1.5, 95%-CI: 0.5-4.5), respectively. In contrast, PET-2-negative NLPHL (n=21) and cHL (n=172) patients treated with 2 cycles of ABVD followed by consolidation radiotherapy had 5-year PFS rates of 100% and 92.3% (95%-CI: 88.1-96.5%) (HR=0; 95%-CI: 0), respectively. NLPHL patients with a typical growth pattern (n=44) had a 5-year PFS of 95.2% (95%-CI: 88.8-100%) whereas patients with an atypical growth pattern (n=23) had a 5-year PFS of 82.2% (95%-CI: 66.3-98%) (HR=2.5; 95%-CI: 0.5-11.2). A total of 9 NLPHL patients experienced disease progression or relapse during follow-up. The median time to NLPHL recurrence was 14 months (range: 1-89 months). There were 2 cases of second primary malignancies (1 case of malignant melanoma, 1 case of stomach cancer) among patients with NLPHL. No patient developed histological transformation into aggressive B-cell non-Hodgkin lymphoma. The 5-year OS rates were 100% and 98.6% (95%-CI: 97.5-99.7%) (HR=0; 95%-CI: 0) for patients with NLPHL and cHL, respectively.Conclusion:Taken together, the 5-year outcomes for patients with newly diagnosed early-stage NLPHL were similar to their counterparts with cHL. Thus, the current standard of care for early-stage cHL consisting of 2 cycles of ABVD followed by consolidation radiotherapy represents a highly active option also for the treatment of patients with the initial diagnosis of stage IB and stage II NLPHL without risk factors. DisclosuresFuchs: Takeda: Consultancy, Honoraria; Lukon: Honoraria; Celgene: Honoraria; BMS: Honoraria; MSD: Honoraria. von Tresckow: AstraZeneca: Honoraria, Other: congress and travel support; Kite-Gilead: Consultancy, Honoraria; BMS-Celgene: Consultancy, Honoraria, Other: congress and travel support; Amgen: Consultancy, Honoraria; AbbVie: Other: congress and travel support; Pfizer: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Other: congress and travel support, Research Funding; Pentixafarm: Consultancy, Honoraria; MSD: Consultancy, Honoraria, Other: congress and travel support, Research Funding; Roche: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Other, Research Funding. Engert: Takeda: Consultancy, Honoraria, Research Funding; BMS: Honoraria, Research Funding; Astra Zeneca: Consultancy, Honoraria; Tessa Therapeutics: Consultancy; Amgen: Honoraria; ADC Therapeutics: Consultancy; MSD: Honoraria; Hexal: Honoraria.

English

BACKGROUND The term Hodgkin’s lymphoma includes classical Hodgkin lymphoma (CHL) and the less common nodular lymphocyte predominant Hodgkin lymphoma (NLPHL). NLPHL is a B cell neoplasm usually characterised by nodular or follicular and diffuse proliferation of small lymphocytes with single scattered large neoplastic cells (LP/L&amp;H/Popcorn cells). NLPHL accounts for 10 % of all Hodgkin lymphoma. METHODS This is a retrospective study. Histopathology slides and blocks of 24 cases of nodular lymphocyte predominant Hodgkin lymphoma were collected from the archives of histopathology from 2011 to 2015. The immunohistochemistry slides of the corresponding histopathology cases were also assembled. Both the slides were reviewed by three expert onco-pathologists and IHC markers were studied and compared. RESULTS Patients were mostly young between 20 and 40 years (16 / 24, 66.67 %). There was a distinct male preponderance (20 / 24, 83.3 %). Most cases involved cervical, axillary or inguinal lymph nodes, with cervical lymph nodes being the most common (13 / 24, 54 %). It was found that CD45, CD20, CD79a and PAX5 staining highlighted the LP cells in all twenty-four cases, while OCT - 2 and BOB - 1 were highlighted in twenty-three cases (95.8 %), which was statistically significant. CD3 and CD5 IHC staining on T cell rosettes and background reactive T cells were examined, and it was seen that CD3 expression was far more consistent than CD5 expression in T cell rosettes and reactive T cells. Also, it was seen that, those cases which were double positive for CD3 and CD5 constitutes only eight cases (8 / 24, 33.3 %). CONCLUSIONS CD3 is a more consistent marker than CD5 in demonstrating surrounding reactive T cells in NLPHL. CD45, PAX5, CD20, BOB - 1 and OCT - 2 are consistent immunohistochemical markers of LP cells. KEYWORDS Nodular Lymphocyte Predominant Hodgkin Lymphoma (NLPHL), Classical Hodgkin Lymphoma (CHL), Cluster Differentiation (CD), Lymphocyte Predominant Cells (LP Cells), Lymphocyte and Histiocytic Cell (L &amp; H Cell)

Utility of Combined EZH2, p-ERK1/2, p-STAT, and MYC Expression in the Differential Diagnosis of EZH2-positive Hodgkin Lymphomas and Related Large B-Cell Lymphomas.

EZH2 is a methyltransferase that plays an important tumorigenic role in various neoplasms. We previously found that EZH2 is expressed in a range of aggressive B-cell lymphomas (ABCLs), T-cell lymphomas, and histiocytic neoplasms, with differential expression of intracellular signaling molecules p-ERK, MYC, and p-STAT3, potential regulators of EZH2 expression. We studied EZH2 expression in nodular lymphocyte predominant Hodgkin lymphoma (NLPHL), classic Hodgkin lymphoma (cHL), T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL), and B-cell Lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphomas and classic Hodgkin lymphoma (BCLu-DLBCL/cHL), as well as the coexpression of p-ERK, MYC, and p-STAT3 in these neoplasms. The neoplastic LP cells of NLPHL and Hodgkin/Reed-Sternberg cells of cHL were strongly positive for EZH2, as were the neoplastic cells in THRLBCL and BCLu-DLBCL/cHL. EZH2 expression correlated with proliferation rate, as assessed by Ki-67 staining. LP cells in NLPHL and Hodgkin/Reed-Sternberg cells in cHL were strongly positive for p-ERK, p-STAT3, and MYC, as were the neoplastic cells in THRLBCL and BCLu-DLBCL/cHL, in contrast to the differential expression of these molecules seen in ABCLs. These findings suggest that combined expression of p-ERK, MYC, and p-STAT3 is a useful immunohistochemical pattern for the diagnosis of EZH2-positive Hodgkin lymphomas and related lymphomas, in contrast to ABCLs. Furthermore, the overexpression of EZH2, in association with coexpression of tumorigenic signaling molecules, suggests an oncogenic role for this molecule in the development of Hodgkin lymphomas and related lymphomas. THRLBCL and BCLu-DLBCL/cHL appear to have a mechanism for the regulation of EZH2 expression that is similar to NLPHL and cHL and different from that of ABCLs. In addition, EZH2 and associated signaling cascades may serve as therapeutic targets for the treatment of Hodgkin lymphomas and related lymphomas.

Diagnostic Utility of Flow Cytometry Analysis of Reactive T Cells in Nodular Lymphocyte-Predominant Hodgkin Lymphoma.

This study aims to define the diagnostic utility of flow cytometric features of T cells in nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL). Cases were retrospectively identified based on diagnosis with NLPHL (n = 30 samples), classic Hodgkin lymphoma (CHL; n = 33), and reactive lymphoid hyperplasia (RLH; n = 43). Pathology slides were reviewed. Flow cytometry list mode data were reanalyzed. The mean proportion of CD4 + CD8 + T cells (8.4%) in cases of NLPHL was significantly higher than seen in CHL (1.0%) or RLH (0.6%). Of the T cells, 28.4% were CD57 + in NLPHL, significantly higher (P < .05) than in CHL (3.2%) or RLH (3.2%). Based on receiver operating characteristic curve analysis, when using a cutoff of 3.0% of CD4 + CD8 + T cells, the diagnostic sensitivity for NLPHL is 83.3% with a specificity of 97.4%. The diagnostic sensitivity was 96.7% with a specificity of 98.7% when using a cutoff of 12% for CD57 + T cells. Increased portions of CD57 + T cells and CD4 + CD8 + T cells are highly suggestive of the possibility of NLPHL. In addition, NLPHL diagnosis appears unlikely if neither CD57 + T cells nor CD4 + CD8 + T cells are increased. Future prospective studies including cases of progressive transformation of germinal center and T-cell/histiocyte-rich large B-cell lymphoma will further define the utility of flow cytometry of T cells in NLPHL.

Insulin-like growth factor I is expressed in classical and nodular lymphocyte-predominant Hodgkin's lymphoma tumour and microenvironmental cells.

Hodgkin's lymphoma (HL) is among the most frequent nodal lymphomas in the Western world and is classified into two disease entities: nodular lymphocyte-predominant Hodgkin's lymphoma (NLPHL) and classical Hodgkin's lymphoma (cHL, 95% of all HL). HL lesions are characterised by a minority of clonal neoplastic cells, namely Hodgkin and Reed-Sternberg (HRS) cells and their variants in cHL and lymphocyte-predominant (LP) cells in NLPHL, both occurring within a microenvironment of, for example, reactive T and B cells, macrophages and granulocytes that are assumed to support the proliferation and maintenance of neoplastic cells through cytokines, chemokines and growth factors. Insulin-like growth factor I (IGF-I) is an important growth factor involved in proliferation, differentiation, apoptosis and cell survival of numerous (including immune) tissues and probably has a role in tumour pathogenesis and maintenance. Although HL is characterised by disturbed cell differentiation and apoptosis mechanisms, with the involvement of the IGF-I receptor (IGF-1R), the distinct location of IGF-I in HL has not yet been defined. We localise IGF-I by double-immunofluorescence in frequent neoplastic cells of all cHL and NLPHL cases investigated. Additionally, IGF-I immunoreactivity is detected in high endothelial venules and various immune cells within the surrounding tissue of cHL including neutrophils and macrophages. IGF-1R immunoreactivity of variable intensity is found in HRS cells and high endothelial venules within the microenvironment in cHL. We assume that autocrine and paracrine IGF-I plays an anti-apoptotic role in tumour pathogenesis and in shaping the tumour microenvironment.

CD75: A B‐cell marker which should not be forgotten in lymphocyte predominant Hodgkin lymphoma

To the Editor The derivation of lymphocyte predominant (LP) cells of nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) from germinal center (GC) B cells is supported by the following features: the expression of the BCL6 gene product and CD40 by LP cells 1, 2; the occurrence of numerous CD4+/PD1 T cells surrounding the LP cells, as seen in normal GCs and progressively transformed GCs (PTGCs); the presence of a follicular dendritic cell (FDC) meshwork (CD21+) within the tumor nodules 3; and the global gene expression profile 3. On these grounds, immunophenotyping by immunohistochemical analysis using B-cell markers for detecting LP cells is generally considered the golden standard in the diagnosis of NLPHL 3. LP cells are positive for CD20, CD79a, CD75, BCL6, Pax5, and OCT2. To evaluate the impact of B-cell markers in detecting LP cells of NLPHL, we analyzed the histopathologic and immunophenotypic patterns of NLPHL from 42 patients (total of 52 samples). These cases were obtained from our files at Aviano Centro di Riferimento Oncologico (CRO) during the period from 1986 to 2005. Immunohistochemical studies were performed on paraffin-embedded sections from formalin-fixed samples and Bouin-fixed samples. Informed written consent was obtained from the patients, and tissue collection was approved by Aviano CRO Institutional Review Board. Immunohistochemical stains were performed with a panel of monoclonal and polyclonal antibodies, listed in Supporting Information, using an automated immunostainer (Ventana Medical Systems, Tucson, AZ) according to the company's protocols. Serial sections were used for assessment of antigen coexpression. The diagnosis of NLPHL was based on the established WHO criteria 3. Typical NLPHL patterns were recognized in 31 patients, while histopathologic variants were found in the remaining 11 patients. The typical NLPHL patterns, including pattern A and pattern B according to Fan et al. 4, consisted of a predominantly nodular growth with non-neoplastic B-cells and LP cells located within the B-cell nodules. The LP cells were rarely found outside the nodules. Conversely, histopathologic NLPHL variants were characterized by the presence of LP tumor cells outside the B-cell nodules. LP cells were positive for all the B cell markers tested in all cases. CD75, also known as CDw75, a marker of mature B cells of GC derivation, was useful in detecting LP cells, especially those admixed with reactive B cells and FDCs in nodules of typical NLPHL patterns (31 out of 42) (Fig. 1). LP cells expressed CD75 strongly, while small reactive B cells with a mantle cell phenotype in the nodules showed weak cytoplasmic positivity in the Golgi area but no membranous staining. The consequence was that in B-cell nodules of typical NLPHL patterns CD75 selectively highlighted LP cells through their cytoplasmic and membranous staining (Fig. 1). CD20 was expressed in LP cells and in the small reactive B cells in the background with an equal intensity of staining. CD20 could be difficult to interpret in B-cell nodules of typical NLPHL patterns, while in areas with B-cell depletion of histopathologic variants of NLPHL the CD20 stained LP cells were detected easier. LP cells stained for CD75 were more numerous than those stained for CD20. The OCT2 and PAX5, B-cell transcription factors were consistently coexpressed. However, their expression was even worse than CD20 in detecting LP cells because these markers preferentially stained small reactive B cells. Our results lead us to conclude that CD75 is superior to other B-cell markers in detecting LP cells, especially in typical NLPHL patterns. Therefore, CD75 should not be forgotten in the immunohistochemical panel for detecting LP cells. Recognizing histopathologic NLPHL patterns is clinically relevant because of the adverse prognostic impact displayed by the histopathologic NLPHL variants as demonstrated by the German Hodgkin Study Group 5 and also because of the favorable prognostic impact displayed by the typical NLPHL patterns as recently reported by us in the American Journal of Haematology 6. Antonino Carbone1* Annunziata Gloghini2 1Department of Pathology, Centro di Riferimento Oncologico Aviano, Istituto Nazionale Tumori, IRCCS, I-33081 Aviano, Italy; 2Department of Diagnostic Pathology and Laboratory Medicine, Fondazione IRCCS, Istituto Nazionale Tumori, I-20133 Milano, Italy Additional Supporting Information may be found in the online version of this article. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Nodular Lymphocyte Predominant Hodgkin Lymphoma and T Cell/Histiocyte Rich Large B Cell Lymphoma - Endpoints of a Spectrum of One Disease?

In contrast to the commonly indolent clinical behavior of nodular lymphocyte predominant Hodgkin lymphoma (NLPHL), T cell/histiocyte rich large B cell lymphoma (THRLBCL) is frequently diagnosed in advanced clinical stages and has a poor prognosis. Besides the different clinical presentations of these lymphoma entities, there are variants of NLPHL with considerable histopathologic overlap compared to THRLBCL. Especially THRLBCL-like NLPHL, a diffuse form of NLPHL, often presents a histopathologic pattern similar to THRLBCL, suggesting a close relationship between both lymphoma entities. To corroborate this hypothesis, we performed gene expression profiling of microdissected tumor cells of NLPHL, THRLBCL-like NLPHL and THRLBCL. In unsupervised analyses, the lymphomas did not cluster according to their entity. Moreover, even in supervised analyses, very few consistently differentially expressed transcripts were found, and for these genes the extent of differential expression was only moderate. Hence, there are no clear and consistent differences in the gene expression of the tumor cells of NLPHL, THRLBCL-like NLPHL and THRLBCL. Based on the gene expression studies, we identified BAT3/BAG6, HIGD1A, and FAT10/UBD as immunohistochemical markers expressed in the tumor cells of all three lymphomas. Characterization of the tumor microenvironment for infiltrating T cells and histiocytes revealed significant differences in the cellular composition between typical NLPHL and THRLBCL cases. However, THRLBCL-like NLPHL presented a histopathologic pattern more related to THRLBCL than NLPHL. In conclusion, NLPHL and THRLBCL may represent a spectrum of the same disease. The different clinical behavior of these lymphomas may be strongly influenced by differences in the lymphoma microenvironment, possibly related to the immune status of the patient at the timepoint of diagnosis.

Intranodular clusters of activated cells with T follicular helper phenotype in nodular lymphocyte predominant Hodgkin lymphoma: a pilot study of 32 cases from Finland

In nodular lymphocyte predominant Hodgkin lymphoma (NLPHL), little is known about the presence of intranodular clusters of cytologically activated lymphoid cells producing a moth-eaten pattern histologically. This pilot study of 32 NLPHL cases from Finland ascertained (1) the frequency of the intranodular clusters of activated lymphoid cells, (2) the immunophenotype of the activated cells, (3) the size and immunophenotype of the rosetting cells, and (4) the clinical significance of the activated cells. Histologically, intranodular clusters of activated cells produced a moth-eaten pattern in 100% (32 cases; subtle in 62.5%, overt in 37.5%). In immunostains, activated cells in subtle clusters (20 cases) were very difficult to identify. Twelve cases had overt clusters of activated cells, which were positive with CD3, CD4, PD1, CXCL13 (T follicular helper [T(FH)] phenotype), but rarely with Ki-67 and BCL2. Most activated rosetting cells had the same immunophenotype as the nonrosetting cells, except for CXCL13. Clinical presentation for all 32 Finnish patients was distinctive: 97% men, 97% with peripheral lymphadenopathy and 35.5% with stage III/IV disease. Only 22% relapsed; 97% were in remission. There was no significant clinical difference between cases with overt and subtle clusters. Intranodular activated TFH cells in NLPHL appeared to be nonproliferating and not long-living, and they were not associated with any adverse clinical outcome. Although most activated cells were TFH cells, it seemed that they were unable to increase the number of malignant cells. The pathogenetic role of the intranodular activated TFH and the small T cells in NLPHL needs further investigation.

Macrophages in T cell/histiocyte rich large B cell lymphoma strongly express metal-binding proteins and show a bi-activated phenotype

Abundant macrophage infiltration in tumors often correlates with a poor prognosis. T cell/histiocyte rich large B cell lymphoma (THRLBCL) is a distinct aggressive B cell lymphoma entity showing a high macrophage content. To further elucidate the role of tumor-associated macrophages in THRLBCL, we performed gene expression profiling of microdissected histiocyte subsets of THRLBCL, nodular lymphocyte predominant Hodgkin lymphoma (NLPHL), Piringer lymphadenitis, sarcoidosis, nonspecific lymphadenitis and monocytes from peripheral blood. In a supervised principal component analysis, histiocytes from THRLBCL were most closely related to epithelioid cells from NLPHL, with both types of cells expressing genes related to proinflammatory and regulatory macrophage activity. Moreover, histiocytes from THRLBCL strongly expressed metal-binding proteins like MT2A, by which histiocytes of THRLBCL can be distinguished from the other histiocyte subsets investigated. Interestingly, the validation at the protein level showed a strong expression of TXN, CXCL9, MT2A and SOD2 not only in macrophages of THRLBCL but also in the tumor cells of NLPHL and classical Hodgkin lymphoma (cHL). Overall, the present findings indicate that macrophages in the microenvironment of THRLBCL have acquired a distinct gene expression pattern that is characterized by a mixed M1/M2 phenotype and a strong expression of several metal binding proteins. The microenvironments in NLPHL and THRLBCL appear to have a similar influence on the macrophage phenotype. The high expression of metal binding proteins in histiocytes of THRLBCL may be diagnostically useful, but a potential pathophysiological role remains to be identified.

Nodular lymphocyte‐predominant Hodgkin lymphoma

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL), a rare subtype of Hodgkin lymphoma, is an indolent tumor with frequent instances of disease recurrence but a favorable prognosis. To the best of the authors' knowledge, there are only limited descriptions of NLPHL in the cytology literature because it was only formally recognized as a distinct entity in 1994. In the current study, all cases of NLPHL diagnosed on excisional biopsy (n = 6 cases) at the study institution between 2000 and 2011 that had undergone previous fine-needle aspiration (FNA) were reviewed, with a focus on cytomorphologic features. Four of 6 cases were termed benign on FNA; however, there was retrospective recognition of characteristic LP cells in all cases. Unlike classical Hodgkin lymphoma, the tumor cells of NLPHL were often found to be mononucleate and presented in a background of small lymphocytes. Other features identified included epithelioid histiocytes and numerous bare atypical nuclei. Cases of NLPHL are commonly misdiagnosed as benign reactive lymphoid tissue and therefore a careful search using high magnification for LP cells is recommended in the evaluation of lymph node FNAs.

Nodular lymphocyte predominant Hodgkin lymphoma and diffuse large B-cell lymphoma: a study of six cases concurrently involving the same site

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a slowly progressing neoplasm with a favourable prognosis. However, in a minority of cases (3-12%) it progresses to a clonally related diffuse large B-cell lymphoma (DLBCL), diagnosed between 6 months and 24 years after NLPHL. This study investigated six cases of NLPHL and DLBCL at the same location. The patients were five men and one woman. In four cases, the site was an axillary lymph node, and in two it was inguinal. In all cases, NLPHL areas had typical morphological and immunophenotypic features. DLBCL involvement was multifocal, diffuse, and characterized by large centroblastic and anaplastic cells. Immunohistochemical studies showed DLBCL cells to be positive for CD20, CD45, and BCL6. In one case, DLBCL cells were positive for BCL2, and in two cases they were positive for MUM-1. There were no networks of follicular dendritic cells (FDC) associated with DLBCL. Rosettes of PD-1-positive and CD57-positive cells surrounding malignant cells in NLPHL were absent in DLBCL. All the cases were negative for Epstein-Barr virus. No translocations involving MYC were identified in DLBCL. Treatment and outcome were known in four cases. All of these patients were treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP), and this was followed by clinical remission (CR). In adequately sampled tumors, DLBCL can be associated with NLPHL at diagnosis. Diffuse architecture, loss of FDC networks, sometimes immunophenotype shift are characteristics of DLBCL associated with NLPHL. Treatment with R-CHOP usually leads to CR.

Frontline Therapy of Nodular Lymphocyte Predominant Hodgkin Lymphoma with Rituximab: The Stanford University Experience

Abstract 2686 Background:Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is a rare subtype of HL (∼5%). This unique clinical entity is characterized by an indolent clinical course and unlike classical HL late relapses may occur. Standard treatment depends on stage and includes radiation therapy (RT) and/or chemotherapy which can be associated with an increased risk of treatment related late effects warranting investigation of other active agents. The malignant cells of NLPHL universally express CD20, therefore therapy with rituximab (R), the monoclonal anti-CD20 antibody, is a targeted option. We report our experience with R as front-line treatment for patients with NLPHL. Methods:Patients with newly diagnosed NLPHL and measurable disease were treated with R at 375 mg/m2 administered weekly × 4 or, after protocol amendment (February 2003) with R followed by 4 doses of R maintenance (RM) administered every 6 months for 2 years. Restaging studies were performed at 1, 3 and 6 months and then every 6 months until progression. All pathology was centrally reviewed. Results:Nineteen patients were enrolled between May 1999 and September 2006. The median age at treatment was 45 years (range 17–63), stage I (n=6), stage II (n=7), stage III (n=6). Ten patients were treated with R alone and 9 with R+RM. The median follow-up for R patients is 8.8 years (5–11.4) and for R+RM patients is 5 years (2.5–7.6). At the end of induction therapy with R alone, the overall response rate was 100% [complete response (CR) (n=10), CR unconfirmed (n=2) and partial response (n=7)]. The median progression free survival (PFS) for patients treated with R alone and R+RM is 50 months and 67 months, respectively (p=0.7; log rank test) and median overall survival (OS) not reached. The median follow up for patients without progressive disease at the time of this analysis was 6.9 years (range 2.5–11.5). The estimated PFS at 5 years is 51.7%, [95% CI 33.2–80.4] and at 10 years 35.4% [95% CI 17.7–70.8]. There was no difference in median PFS between patients with stages I-II versus III (5.6 years and 4.15 years respectively, p=0.58 [log rank test]). The estimated OS at 5 years is 93.3%, [95% CI 81.5–100] and 10 years 76% [95% CI 55.4–100]. Ten patients progressed (5 treated with R alone, 5 treated with R+RM) of whom 6 transformed to an aggressive B cell lymphoma (biopsy proven) at a median of 4.2 years [range 0.9–8]. Five of the 6 transformed patients had abdominal disease at initial diagnosis (stage III, n=4). Three patients died (2 aggressive NHL, 1 unknown). Conclusion:Rituximab is an active single agent in the treatment of newly diagnosed NLPHL with a median PFS of 5.6 years. R+ RM resulted in a non-significant increase in PFS compared to R alone. In this series, abdominal involvement was associated with transformation to an aggressive B cell lymphoma underscoring the need for biopsy at relapse. These results demonstrate a pattern of late relapse following rituximab, at least as great as the historical data with RT or RT + CT. Although R alone achieved proof of concept for a targeted therapy, its use should remain investigational as primary therapy of NLPHL. Disclosures:Advani:Genentech Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding. Off Label Use: Rituximab. Anti-CD20 agent that targets CD20 on NLPHL cells. Horning:Genentech: Employment, Equity Ownership.

Hodgkin's lymphoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

D. A. Eichenauer1, A. Engert1, M. Andre2, M. Federico3, T. Illidge4, M. Hutchings5, & M. Ladetto6 on behalf of the ESMO Guidelines Working Group* First Department of Internal Medicine, University Hospital Cologne and German Hodgkin Study Group (GHSG), Cologne, Germany; CHU Dinant-Godinne, UCL Namur, Yvoir, Belgium; Department of Oncology, Hematology and Respiratory Diseases, University of Modena and Reggio Emilia, Modena, Italy; Institute of Cancer Sciences, University of Manchester, Manchester, UK; Department of Hematology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark; Divisione di Ematologia, Azienda Ospedaliera Santi Antonio e Biagio e Cesare Arrigo, Alessandria, Italy

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) with CD30-positive lymphocyte-predominant (LP) cells.

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a distinct neoplasm within the spectrum of Hodgkin lymphomas with characteristic clinical, morphological, and immunohistochemical features. According to the WHO definition, lymph nodes involved by NLPHL should have a nodular or nodular and diffuse proliferation of scattered large neoplastic lymphocyte-predominant (LP) cells in a small cell background that reside in expanded follicular dendritic cell meshworks; the LP cells must also have a distinct immunophenotypic profile. The LP cells are monoclonal B cells that are typically CD20, BCL6, CD79a, and CD45 positive and are CD30 and CD15 negative. In contrast, the Reed-Sternberg cells of classical Hodgkin lymphoma (CHL) are typically positive for CD15 and CD30. However, in CHL, CD20 staining is variable, and CD15 staining may be absent in some cases. Thus, CD30 is often considered to be the most distinctive marker between CHL and NLPHL. In order to better assess CD30 staining in NLPHL, we reviewed 220 cases of NLPHL and found 21 cases that showed at least focal staining of the neoplastic cells for CD30. The CD30 staining was often faint, but occasionally strong, and typically was found only on a subset of the LP cells. We evaluated the clinicopathologic features of these cases to determine whether they showed differences from typical CD30-negative NLPHL and found no significant difference with respect to clinical presentation, histology, other immunophenotypic features or outcome. In summary, we conclude that CD30 expression by LP cells in NLPHL can be seen and should not lead to a misdiagnosis of CHL. The presence of CD30-positive LP cells is not associated with other features of CHL or unusually aggressive behavior.

Molecular Pathogenesis of Hodgkin's Lymphoma: Increasing Evidence of the Importance of the Microenvironment

Hodgkin's lymphoma (HL) represents the most common subtype of malignant lymphoma in young people in the Western world. Most patients can be cured with modern treatment strategies, although approximately 20% will die after relapse or progressive disease. The histologic hallmark of the disease is the presence of the characteristic Hodgkin Reed-Sternberg (HRS) cells in classical HL and so-called lymphocyte-predominant (LP) cells in nodular lymphocyte-predominant HL. HL is unique among all cancers because malignant cells are greatly outnumbered by reactive cells in the tumor microenvironment and make up only approximately 1% of the tumor. Expression of a variety of cytokines and chemokines by the HRS and LP cells is believed to be the driving force for an abnormal immune response, perpetuated by additional factors secreted by reactive cells in the microenvironment that help maintain the inflammatory milieu. The malignant HRS and LP cells manipulate the microenvironment, permitting them to develop their malignant phenotype fully and evade host immune attack. Gene expression signatures derived from non-neoplastic cells correlate well with response to initial and subsequent therapies, reflecting their functional relevance. Recent biomarker studies have added texture to clinical outcome predictors, and their incorporation into prognostic models may improve our understanding of the biologic correlates of treatment failure. Moreover, recent preclinical and clinical studies have demonstrated that the tumor microenvironment represents a promising therapeutic target, raising hope that novel treatment strategies focused on the interface between malignant and reactive cells will soon emerge.