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

Diagnosis of Hodgkin lymphoma in the modern era

The Hodgkin lymphomas are a family of unique lymphoma subtypes, in which the nature of the neoplastic cell was enigmatic for many years. Much of the mystery has been solved, with all forms now considered to be of B-cell origin, in most cases of germinal centre derivation. Today we recognize Hodgkin lymphoma as an eponym that encompasses multiple entities. One of the unifying themes is the major contribution from the tumour microenvironment. Both the character of the neoplastic cells and the nature of the immune environment are critical to accurate diagnosis. Moreover, an understanding of the molecular alterations that characterize both the neoplastic cells and their microenvironment have led to therapeutic advances, targeting both neoplastic and reactive components. Other conditions may foster a similar inflammatory milieu and lead to lymphoproliferations that mimic the Hodgkin lymphomas. In this review we provide an update on the diagnostic features of the various subtypes and include additional information relevant for prognostic evaluation and investigation of potential therapeutic targets. Additionally, we also discuss those conditions that often cause confusion in diagnosis and need to be distinguished from the Hodgkin lymphomas.

A strong host response and lack of MYC expression are characteristic for diffuse large B cell lymphoma transformed from nodular lymphocyte predominant Hodgkin lymphoma

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is an indolent lymphoma, but can transform into diffuse large B cell lymphoma (DLBCL), showing a more aggressive clinical behavior. Little is known about these cases on the molecular level. Therefore, the aim of the present study was to characterize DLBCL transformed from NLPHL (LP-DLBCL) by gene expression profiling (GEP). GEP revealed an inflammatory signature pinpointing to a specific host response. In a coculture model resembling this host response, DEV tumor cells showed an impaired growth behavior. Mechanisms involved in the reduced tumor cell proliferation included a downregulation of MYC and its target genes. Lack of MYC expression was also confirmed in 12/16 LP-DLBCL by immunohistochemistry. Furthermore, CD274/PD-L1 was upregulated in DEV tumor cells after coculture with T cells or monocytes and its expression was validated in 12/19 cases of LP-DLBCL. Thereby, our data provide new insights into the pathogenesis of LP-DLBCL and an explanation for the relatively low tumor cell content. Moreover, the findings suggest that treatment of these patients with immune checkpoint inhibitors may enhance an already ongoing host response in these patients.

Relapsed or poorly responsive nodular lymphocyte predominant Hodgkin lymphoma in children and adolescents - a report from the United Kingdom's Children's Cancer and Leukaemia Study Group

There is a paucity of data on the treatment outcome in children with relapsed or poorly responsive nodular lymphocyte predominant Hodgkin lymphoma (nLPHL). This retrospective report evaluates the treatment outcome in a national cohort of children with relapsed or poorly responsive nLPHL. A total of 37 patients, 22 with relapsed and 15 with poorly responding disease, are the subjects of this report. Of the 22 patients with relapsed nLPHL, 11 had relapsed after primary excision biopsy, 10 after chemotherapy and 1 after chemotherapy and involved field radiotherapy. The majority had localized disease at relapse. The median time to relapse was 8 months after chemotherapy and 11 months after excision biopsy. Seven of the 15 patients with poorly responding nLPHL had variant histology. Three patients with initial poor response did not receive any further treatment and have had no disease progression. Transformation to diffuse large B cell lymphoma, in addition to evolution from typical to variant nLPHL occurred in one patient each. Thirty-four patients have been successfully re-treated with second chemotherapy or radiotherapy. Multiple relapses were uncommon but treatable. Relapse or poorly responsive nLPHL is fully salvageable with either additional chemotherapy and or radiotherapy.

Nodular lymphocyte predominant Hodgkin lymphoma: Clincopathological study of 25 cases from Japan with a reappraisal of tissue associated macrophages

Clinicopathological features of 25 nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) patients in Japan were analysed. To investigate the clinicopathological significance of tissue associated macrophages (TAM) in NLPHL, CD68 and CD163 expression were investigated. The median age at onset was 56 years (range: 6-82 years) with male predominance (64%). All patients presented with lymph node enlargement with predilection for cervical LNs. Seven cases (28%) had mediastinal lesion and four (16%) had extranodal involvement. Most cases (76%) presented with early clinical stages. After median follow up of 44 months, both of overall and progression free survival rates were 95%. The presence of >5% CD68+ TAM in NLPHL was significantly associated with older age at diagnosis (median, 71 vs 52.5 years; P = 0.048), lower hemoglobin level (33.3% vs 0%; P = 0.037) and lower CR rate after initial treatment (42.9% vs 91.7%; P = 0.038). The presence of >5% CD163+ TAM was significantly correlated with presence of B symptoms (40% vs 0%; P = 0.036). In conclusion, NLPHL is rare among Japanese and appears to present at an older age than among Western patients. In our series, the presence of >5% CD68+ TAM in NLPHL was associated with lower CR rate, but with no impact on patients' survival.

Pidilizumab in the treatment of diffuse large B-cell lymphoma

INTRODUCTION

The programmed death-1 (PD-1) immune checkpoint pathway is an emerging target in the treatment of hematologic malignancies. Pidilizumab is an mAb that binds to PD-1 and is a safe and well-tolerated therapy. Recent data have shown clinical activity utilizing this strategy in diffuse large B-cell lymphoma (DLBCL).

AREAS COVERED

The role of PD-1 expression in hematologic malignancies is explored. Recent clinical trials including the results of a Phase I trial in hematologic malignancies and a Phase II trial of pidilizumab following autologous hematopoietic stem-cell transplant (AHSCT) are reviewed.

EXPERT OPINION

We review data that suggest that PD-1 is a promising target in the treatment and management of DLBCL. Changes in immune subsets following administration of pidilizumab are felt to represent on-target responses. The improvement in progression-free survival (PFS) following AHSCT supports a response to therapy. Importantly, the improvement in PFS for patients with positive FDG-PET/CT following AHSCT indicating residual disease further supports direct activity of pidilizumab in DLBCL.

Diffuse large B cell lymphoma derived from nodular lymphocyte predominant Hodgkin lymphoma presents with variable histopathology

Background

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) usually presents in middle aged men and shows an indolent clinical behavior. However, up to 30% of the patients present a secondary transformation into aggressive diffuse large B cell lymphoma (DLBCL). The aim of the present study was to characterize morphology and immunophenotype of this kind of DLBCL in detail and compare it with conventional DLBCL.

Methods

Morphology and immunophenotype of 33 cases of NLPHL with simultaneous or sequential transformation into DLBCL were investigated. These cases were compared with 41 de novo DLBCL in Finnish men.

Results

The majority of cases exhibited different immunophenotypes in the NLPHL and the DLBCL components. The immunophenotype of the DLBCL secondary to NLPHL was heterogeneous. However, BCL6, EMA, CD75 and J-chain were usually expressed in both components (≥73% positive). Overall, the NLPHL component was more frequently positive for EMA, CD75 and J-chain than the DLBCL component. In contrast, B cell markers, CD10 and BCL2, were more frequently expressed and were expressed at higher levels in the DLBCL component than in the NLPHL component. In the independent series of de novo DLBCL 4 cases could be identified with a growth pattern and immunophenotype that suggested that they had arisen secondarily from NLPHL.

Conclusions

The morphology and immunophenotype of DLBCL arisen from NLPHL is heterogeneous. Further characterization of the particular molecular features of this subgroup is warranted to be able to better identify these cases among conventional DLBCL.

Follicular dendritic cells: origin, function, and different disease-associated patterns

Follicular dendritic cells (FDCs) are a specialized type of antigen-presenting dendritic cells that are largely restricted to lymphoid follicles. They form dense three-dimensional meshwork patterns within benign follicles, which maintain the follicular architecture. The FDC function is to bind and retain antigens by linking to complement and immune complexes and then present these antigens to germinal center B cells that start the secondary immune response. FDCs aid in the rescue of bound B cells from apoptosis, and induce the differentiation of B cells into long-term memory B cell clones or plasma cells. We will discuss the different patterns of the FDC meshwork observed in different types of reactive and neoplastic disorders, which may be due to underlying different roles that FDCs may play in these disorders and whether changes in the architecture of the FDC meshwork can be useful in routine diagnostic practice or have a prognostic value.

Nodular lymphocyte predominant Hodgkin lymphoma in children and adolescents--a comprehensive review of biology, clinical course and treatment options

Nodular lymphocyte predominant Hodgkin lymphoma (nLPHL) is a unique variant of Hodgkin lymphoma with an overall good prognosis. It is conspicuously different from classical Hodgkin lymphoma (cHL) and is now recognized as distinctive form of B cell lymphoma. Although it has an indolent clinical course, it has a propensity for multiple and often late relapses. Although the majority of children present with early stage disease and without B symptoms, treatment strategy has, until recently, been identical to that used for cHL. This approach is excessively toxic as it predisposes these children and adolescents to serious late effects including end organ damage to heart, gonads, lungs, thyroid and second malignant neoplasms. The aim of this article is to review the published literature on the treatment outcomes of nLPHL in affected children and adolescents, and discuss the options for treatment including surgery, chemotherapy, radiotherapy and targeted anti-CD 20 antibody therapy.