Histology of Bronchiolar Tumor Spread Through Air Spaces

The clinical significance of lung tumor spread through air spaces (STAS) has been extensively studied, and is recognized as a unique pattern of invasion. Previous studies of STAS have focused primarily on STAS in alveolar spaces, whereas STAS in the bronchiolar spaces (bronchiolar STAS) has been described in only a few case reports only. Here, we examined 306 cases of primary lung adenocarcinoma and found that bronchiolar STAS was present in 18%. Bronchiolar STAS was associated with an inferior prognosis, more advanced stage, and higher histologic grade. No significant difference in clinicopathological factors or prognosis was observed between cases with bronchiolar STAS and those with alveolar STAS alone. Notably, bronchiolar STAS often occurred simultaneously with alveolar STAS and endobronchial spread of adenocarcinoma, particularly when bronchiolar STAS was present outside the main tumor. We also identified cases where bronchiolar STAS and endobronchial spread of adenocarcinoma occurred simultaneously in the same bronchi or bronchioles located outside the main tumor, as well as cases with bronchiolar STAS adjacent to intrapulmonary metastatic nodules. Our results highlight the significant role of bronchiolar STAS in the aerogenous spread of adenocarcinoma cells. Bronchiolar STAS can be regarded as a histologic variant of alveolar STAS. This study also supports the idea that STAS is not a tissue processing artifact, but a true biological process with clinical implications, offering histologic evidence of aerogenous spread in lung adenocarcinoma.

Regulatory T-cells activated in metastatic draining lymph nodes possibly suppress cancer immunity in cancer tissues of head and neck squamous cell cancer

Regulatory T cells (Tregs) play an important role in creating an immunosuppressive microenvironment in cancer tissues. However, the mechanisms by which Tregs are activated and suppress cancer immunity remain unclear. To elucidate these mechanisms, we performed a T cell receptor (TCR) repertoire analysis of Tregs and conventional T cells in peripheral blood, draining lymph nodes (DLNs), and cancer tissues of patients with head and neck squamous cell cancer (HNSCC). We found that the TCR repertoire was skewed in cancer tissue and metastatic DLNs (M-DLNs) compared with non-metastatic DLNs, and TCR repertoire similarities in Tregs and CD8+ T cells between M-DLNs and cancer tissue were high compared with those at other sites. These results suggest that Tregs and CD8+ T cells are activated in M-DLNs and cancer tissues by cancer antigens, such as neoantigens, and shared antigens and Tregs suppress CD8+ T cell function in a cancer antigen-specific manner in M-DLNs and cancer tissue. Moreover, M-DLNs might be a source of Tregs and CD8+ T cells recruited into the cancer tissue. Therefore, targeting Tregs in M-DLNs in an antigen-specific manner is expected to be a novel immunotherapeutic strategy for HNSCCs.

Endobronchial spread of adenocarcinoma is a distinct pattern of invasion and associated with inferior clinical outcomes in lung adenocarcinoma

AIM

The spread of lung adenocarcinoma cells into the bronchi and bronchioles is not well documented. We termed this histological finding "endobronchial spreading of adenocarcinoma" (EBSA) and investigated its prevalence and clinical significance.

METHODS AND RESULTS

We reviewed 320 resected specimens from patients diagnosed with invasive adenocarcinoma, and EBSA was observed in 144 patients (45%). EBSA was significantly associated with advanced pathological stage, higher histological grade, larger tumour invasion, lymphovascular infiltration, and spread through air spaces. Patients with EBSA had significantly shorter relapse-free survival (RFS) and cancer-specific survival (CSS) in univariate analysis (P < 0.001). In a subgroup analysis of patient with small-sized (invasion size ≤30 mm) adenocarcinoma in the localized stage, EBSA was an independent inferior prognostic indicator in multivariate analysis. In a subgroup analysis of patients with small-sized Grade 1 nonmucinous adenocarcinoma (n = 61), EBSA was observed in 11 patients, and the presence of EBSA was associated with significantly shorter RFS and CSS (P = 0.026 and P = 0.001, respectively).

CONCLUSION

Our results demonstrated that EBSA is a significant risk factor for disease recurrence and cancer-related deaths. EBSA can be regarded as a distinctive pattern of invasion and its recognition can be beneficial in the diagnosis of lung adenocarcinoma.

PTEN loss in intraductal carcinoma of the prostate has low incidence in Japanese patients

Clinical and genomic features of prostate cancer (PCa) vary considerably between Asian and Western populations. PTEN loss is the most frequent abnormality in intraductal carcinoma of the prostate (IDC-P) in Western populations. However, its prevalence and significance in Asian populations have not yet been well studied. In the present study, we evaluated PTEN expression in IDC-P in a Japanese population and its association with ERG expression. This study included 45 and 59 patients with PCa with and without IDC-P, respectively, who underwent radical prostatectomy. PTEN loss was observed in 10 patients with PCa with IDC-P (22%) and nine patients with PCa without IDC-P (17%). ERG expression was relatively frequent in patients with PCa with PTEN loss, although a significant difference was not observed. The co-occurrence of PTEN loss and ERG expression was observed in four patients with PCa with IDC-P and one without IDC-P. PTEN loss and ERG expression did not affect progression-free survival, regardless of the presence of IDC-P. The frequency of PTEN loss in IDC-P is lower in Asian patients than in Western patients. Our results indicate that mechanisms underlying IDC-P in Asian populations are different from those of Western populations.

Immune Status of Cervical Lymph Nodes in Head and Neck Cancer-A Surgical Oncology Perspective

Neck dissection for cervical lymph node metastasis is an established procedure for head and neck cancer (HNC). However, with the advent of immunotherapy, head and neck surgical oncologists need to rethink removing all lymph nodes, including those with immune function. We investigated the anti-cancer immune response of the cervical lymph nodes in four patients with human papillomavirus type 16 (HPV16)-positive head and neck squamous cell carcinoma. Using lymphocytes extracted from local, metastatic, and non-metastatic lymph nodes and peripheral blood from these patients, we performed an intracellular flow cytometric cytokine assay using anti-IFNγ and anti-TNF-α monoclonal antibodies to detect HPV16 E6- and E7-specific T cells. HPV status and p16 immunostaining were determined by in situ detection using the HPV RNAscope method and immunohistochemistry. In one case, E6-specific and E7-specific CD8+ T cells were detected in proximal metastatic nodes and distal non-metastatic nodes. This finding suggests that non-metastatic nodes should be preserved for their immune function during neck dissection and that the immune function of non-metastatic lymph nodes is important when administering immunotherapy. In this context, head and neck surgical oncologists treating HNC should consider the place of immunotherapy and neck dissection in the treatment of HNC.

Diagnostic Utility of STAT6 and pSTAT6 Immunohistochemistry for Distinguishing Classic Hodgkin Lymphoma and Peripheral T-Cell Lymphoma With Hodgkin and Reed-Sternberg-like Cells

Peripheral T-cell lymphomas (PTCLs), particularly nodal lymphomas of T-follicular helper cell origin, may include Hodgkin/Reed-Sternberg (HRS)-like cells in their microenvironment. These HRS-like cells are morphologically indistinguishable from HRS cells of classic Hodgkin lymphoma (CHL). Therefore, PTCLs with HRS-like cells pose a differential diagnosis vis-à-vis CHL. A previous study reported that, in contrast to HRS cells, programmed death-ligand 1 (PD-L1) expression is rare in HRS-like cells of PTCLs and suggested that PD-L1 immunohistochemistry is useful to differentiate HRS cells and HRS-like cells. In this study, we analyzed 21 patients with PTCL with HRS-like cells and 34 patients with CHL and assessed the diagnostic utility of STAT6, pSTAT6, and pSTAT3 immunohistochemistry in distinguishing HRS cells from HRS-like cells. In addition, we also performed PD-L1 immunohistochemistry to reconfirm its utility in distinguishing the 2 diseases. Compared with HRS cells in CHLs, HRS-like cells in PTCLs showed significantly less positivity for STAT6 (9.6% vs. 70%, P<0.001), pSTAT6 (9.6% vs. 70%, P<0.001), and PD-L1 (9.6% vs. 85%, P<0.001). Thus, we reconfirmed the diagnostic utility of PD-L1 immunohistochemistry in distinguishing CHLs from PTCLs with HRS-like cells. In contrast, both HRS-like and HRS cells were highly associated with pSTAT3 expression, with no significant difference in positive cell frequency (86% vs. 91%, P=0.66). On the basis of these findings, we conclude that, in addition to PD-L1, STAT6 and pSTAT6 immunohistochemistry are helpful diagnostic tools to distinguish CHLs from PTCLs with HRS-like cells.

The Immunology of DLBCL

Diffuse large B-cell lymphoma (DLBCL) is an aggressive malignancy and is the most common type of malignant lymphoid neoplasm. While some DLBCLs exhibit strong cell-autonomous survival and proliferation activity, others depend on interactions with non-malignant cells for their survival and proliferation. Recent next-generation sequencing studies have linked these interactions with the molecular classification of DLBCL. For example, germinal center B-cell-like DLBCL tends to show strong associations with follicular T cells and epigenetic regulation of immune recognition molecules, whereas activated B-cell-like DLBCL shows frequent genetic aberrations affecting the class I major histocompatibility complex. Single-cell technologies have also provided detailed information about cell-cell interactions and the cell composition of the microenvironment of DLBCL. Aging-related immunological deterioration, i.e., immunosenescence, also plays an important role in DLBCL pathogenesis, especially in Epstein-Barr virus-positive DLBCL. Moreover, DLBCL in "immune-privileged sites"-where multiple immune-modulating mechanisms exist-shows unique biological features, including frequent down-regulation of immune recognition molecules and an immune-tolerogenic tumor microenvironment. These advances in understanding the immunology of DLBCL may contribute to the development of novel therapies targeting immune systems.

Diagnostic approach for classic Hodgkin lymphoma in small samples with an emphasis on PD-L1 expression and EBV harboring in tumor cells: a brief review from morphology to biology

Classic Hodgkin lymphoma (CHL) was first described in 1832 by Thomas Hodgkin, and is characterized by a small number of Hodgkin and Reed-Sternberg cells in a rich inflammatory background. However, even in this modern era, due to the histological and biological overlap with CHL and other B-cell malignancies, including mediastinal grey zone lymphoma and other lymphomas accompanied by "Hodgkinoid cells", their discrimination is challenging and sometimes impossible. The complexity and ambiguity of the boundaries of CHL and its related diseases make the definition of CHL unresolved. Our group has studied the significance of PD-L1 expression and infection of Epstein-Barr virus (EBV) in the diagnosis of CHL, emphasizing their pathological role, clinical significance, and high reproducibility even in daily clinical practice. In this review, we summarize the diagnostic strategy of CHL and its histological lookalikes based on neoplastic PD-L1 expression and infection of EBV, and attempt a reappraisal of the definition of CHL.

An Update on the Pathology and Molecular Features of Hodgkin Lymphoma

Simple Summary

Hodgkin lymphomas (HLs) include two main types, classic HL (CHL) and nodular lymphocyte predominant HL (NLPHL). Recent molecular findings in HLs have contributed to dramatic changes in the treatment and identification of tumor characteristics. For example, PD-1/PD-L1 blockade and brentuximab vedotin, an anti-CD30 antibody bearing a cytotoxic compound, are now widely used in patients with CHL. Biological continuity between NLPHL and T-cell/histiocyte-rich large B-cell lymphoma has been highlighted. An era of novel therapeutics for HL has begun. The aim of this paper is to review the morphologic, immunophenotypic, and molecular features of CHL and NLPHL, which must be understood for the development of novel therapeutics.

Abstract

Hodgkin lymphomas (HLs) are lymphoid neoplasms derived from B cells and consist histologically of large neoplastic cells known as Hodgkin and Reed–Sternberg cells and abundant reactive bystander cells. HLs include two main types, classic HL (CHL) and nodular lymphocyte predominant HL (NLPHL). Recent molecular analyses have revealed that an immune evasion mechanism, particularly the PD-1/PD-L1 pathway, plays a key role in the development of CHL. Other highlighted key pathways in CHL are NF-κB and JAK/STAT. These advances have dramatically changed the treatment for CHL, particularly relapsed/refractory CHL. For example, PD-1 inhibitors are now widely used in relapsed/refractory CHL. Compared with CHL, NLPHL is more characterized by preserved B cell features. Overlapping morphological and molecular features between NLPHL and T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) have been reported, and biological continuity between these two entities has been highlighted. Some THRLBCLs are considered to represent progression from NLPHLs. With considerable new understanding becoming available from molecular studies in HLs, therapies and classification of HLs are continually evolving. This paper offers a summary of and update on the pathological and molecular features of HLs for a better understanding of the diseases.

PD-L1-expressing extranodal diffuse large B-cell lymphoma, NOS with and without PD-L1 3'-UTR structural variations

Immune evasion mediated by PD-L1 plays an important role in the development of B-cell malignancies. However, PD-L1 expression is infrequently observed in tumor cells of extranodal diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS). Other than copy number alterations, PD-L1 is aberrantly upregulated by structural variations in the 3′-UTR of PD-L1. We report four cases with PD-L1 expression on tumor cells, including two with structural variations in the 3′-UTR of PD-L1 and two without. Our report demonstrates the presence of a small number of “immune evasion-type” extranodal DLBCL, NOS cases.

TGFB1 mRNA expression is associated with poor prognosis and specific features of inflammation in ccRCC

To determine whether TGFB1 affects the immune microenvironment of ccRCC, we investigated the association between TGFB1 expression and clinicopathological features. Tissue microarray was generated from 158 total or partial nephrectomy samples and 12 tumor-adjacent normal kidney tissue. TGFB1 expression was assessed by RNA in situ hybridization and quantified using ImageJ software. TGFB1 was significantly upregulated in ccRCC tissue than in normal kidney tissues (P = 1.03 × 10^-9). Tumors with a high WHO/ISUP grade had higher TGFB1 expression levels (P = 7.05 × 10^-3). Of 139 patients with localized ccRCC and whose follow-up data were available, those in the TGFB1-high group displayed significantly shorter relapse-free survival than those in the TGFB1-low group (P = 0.0251). TGFB1 expression was significantly upregulated in patients who developed distant metastasis after surgery (n = 12) than in patients without metastasis (n = 127; P = 0.00167). TGFB1 expression positively correlated with the number of PD-L1-positive cells in the tumor stroma (P = 0.0206, ρ = 0.163). Furthermore, TGFB1 expression was associated with the formation of tertiary lymphoid structures. TGF-β1 is a prognostic indicator of worse outcome for ccRCC and might be a therapeutic target in advanced ccRCC. Our data provide new insights into the association between tumor biology and tumor microenvironment in ccRCC.

Clinicopathologic analysis of malignant or premalignant cutaneous neoplasms in Japanese kidney transplant recipients

It is well known that recipients of kidney transplants are at an increased risk of developing malignant or premalignant cutaneous neoplasms (MPCNs) after transplantation. However, the pathogenesis of MPCNs after kidney transplant has not been well-studied in Asian populations. This study aimed to describe the clinicopathologiccharacteristics of MPCNs in an Asian population. We retrospectively reviewed the medical records of 1956 patients who received kidney transplants at two hospitals in Japan, between 2003 and 2019. Among these patients, 24 developed 50 MPCN lesions, including 14 squamous cell carcinoma (SCC, 28%), 23 Bowen's disease (BD, 46%), 11 actinic keratosis (AK, 22%), and two basal cell carcinoma (BCC, 4%). No patient had malignant melanoma. The duration from transplantation to the diagnosis was significantly longer for SCC than for BD or AK (P=0.021, 0.036, respectively). Seven patients had multiple MPCNs in sun-exposed areas of skin. Among the 50 MPCNs, 40 (80%) were located in sun-exposed areas, and 10 (20%) were located in sun-protected areas. MPCNs in sun-exposed skin were frequently accompanied by dermal solar elastosis (90%, 36/40). We found high-risk human papillomavirus (HR-HPV) infections in two anogenital lesions (100%, 2/2). In contrast, HR-HPV infections were not detected in any extragenital lesions (0%, 0/30). Our results suggested that, among Japanese recipients of kidney transplant, MPCNs in sun-exposed skin areas may be associated with immunosuppression and ultraviolet exposure.

Clinicopathologic Analysis of Primary Adrenal Diffuse Large B-Cell Lymphoma: A Reappraisal of 23 Japanese Patients Based on EBV Association and PD-L1 Expression in Tumor Cells

Primary adrenal diffuse large B-cell lymphoma (PA-DLBCL) is rare. We investigate 23 Japanese patients with PA-DLBCL to understand the clinicopathologic features and biological behavior of this disease. The 17 males and 6 females had a median age of 74 years (range: 40 to 86 y). Tumor cells harbored Epstein-Barr virus-encoded small RNA (EBER) in 9 (39%) samples, including samples from the 2 patients with methotrexate-associated B-cell lymphoproliferative disorder. Programmed cell death ligand 1 (PD-L1) expression was detected in tumor cells of 6 (26%) samples, including 1 EBER+ and 5 EBER- samples. Four (17%) patients exhibited an intravascular proliferating pattern, and all 4 patient samples showed positive staining for PD-L1 in tumor cells. Among those patients, 3 showed intravascular proliferating pattern accompanied by a diffuse extravascular proliferation of tumor cells, and 1 patient was diagnosed with intravascular large B-cell lymphoma. We divided the 23 patients into 3 groups: EBER+ (n=9, 39%), EBER-PD-L1+ (n=5, 22%), and EBER-PD-L1- (n=9, 39%). A comparison of the outcomes among the 3 groups showed significant differences in overall survival (P=0.034). The EBER+ group had the worst prognosis, and the EBER-PD-L1- group had the best prognosis. We also compared the outcomes among the 3 groups that received rituximab-containing chemotherapies. Both the overall survival and progression-free survival were significantly different among these groups (P<0.001 and P=0.002, respectively). In conclusion, we evaluated 3 types of PA-DLBCL and found that each had unique clinical, pathologic, and prognostic features. Our results suggested that immune senescence, iatrogenic immunodeficiency, and immune evasion contribute to the development of PA-DLBCL.

Lymphocyte-depleted classic Hodgkin lymphoma with primary extranodal disease: Two cases that highlight the combination of immunodeficiency and immune escape in the pathogenesis

Neoplastic programmed cell death ligand 1 (PD-L1) expression, activated by PD-L1 gene alterations, is strongly associated with classic Hodgkin lymphoma (CHL). This association enabled a diagnostic consensus for lymphocyte-depleted CHL (LD-CHL), a previously enigmatic disease. We describe two patients with LD-CHL and primary extranodal disease. One patient was a 92-year-old female (Case #1) with a large mass that involved the uterus combined with swollen lymph nodes in the pelvic cavity. The second patient was a 76-year-old female (Case #2) with human T-cell leukemia virus type 1 (HTLV-1) who initially exhibited massive bone marrow involvement without peripheral lymphadenopathies. Biopsies of these tumors from the cervix uteri and bone marrow, respectively, revealed lesions rich in Hodgkin and Reed-Sternberg (H-RS) cells and diminished populations of other cell populations. Immunohistochemistry demonstrated that these H-RS cells expressed CD30, BOB1, and fascin, but not CD15, CD20, PAX5, or OCT2. They also expressed PD-L1, which led to our preferred diagnosis of LD-CHL in both patients. Epstein-Barr virus was associated with LD-CHL in Case #1, but not in Case #2. Both patients were deemed too frail for treatment. They died of disease at 1 (Case #1) and 15 months (Case #2) after the diagnosis. These findings highlight the abnormal biological behavior of this immune-escape-related lymphoid neoplasm in patients with immunodeficiency due to immune senescence and HTLV1 infection.

Diagnostic utility of programmed cell death ligand 1 (clone SP142) immunohistochemistry for malignant lymphoma and lymphoproliferative disorders: A brief review

The programmed cell death 1 (PD1)/PD1 ligand (PD-L1) axis plays an important role in tumor cell escape from immune control and has been most extensively investigated for therapeutic purposes. However, PD-L1 immunohistochemistry is still not used widely for diagnosis. We review the diagnostic utility of PD-L1 (by clone SP142) immunohistochemistry in large-cell lymphomas, mainly consisting of classic Hodgkin lymphoma (CHL) and diffuse large B-cell lymphoma (DLBCL). Neoplastic PD-L1 (nPD-L1) expression on Hodgkin and Reed-Sternberg cells is well-established among prototypic CHL. Of note, EBV+ CHL often poses a challenge for differential diagnosis from peripheral T-cell lymphoma with EBV+ non-malignant large B-cells; their distinction is based on the lack of PD-L1 expression on large B-cells in the latter. The nPD-L1 expression further provides a good diagnostic consensus for CHL with primary extranodal disease conceivably characterized by a combined pathogenesis of immune escape of tumor cells and immunodeficiency. Compared with CHL, the nPD-L1 expression rate is much lower in DLBCL, highlighting some specific subgroups of intravascular large B-cell lymphoma, primary mediastinal large B-cell lymphoma, and EBV+ DLBCL. They consist of nPD-L1-positive and -negative subgroups, but their clinicopathological significance remains to be elucidated. Microenvironmental PD-L1 positivity on immune cells may be associated with a favorable prognosis in extranodal DLBCL. PD-L1 (by SP142) immunohistochemistry has helped us to understand the immune biology of lymphoid neoplasms possibly related by immune escape and/or immunodeficiency. However, knowledge of these issues remains limited and should be clarified for diagnostic consensus in the future.

Improving function of cytotoxic T-lymphocytes by transforming growth factor-β inhibitor in oral squamous cell carcinoma

Immunotherapy with immune‐checkpoint therapy has recently been used to treat oral squamous cell carcinomas (OSCCs). However, improvements in current immunotherapy are expected because response rates are limited. Transforming growth factor‐β (TGF‐β) creates an immunosuppressive tumor microenvironment (TME) by inducing the production of regulatory T‐cells (Tregs) and cancer‐associated fibroblasts and inhibiting the function of cytotoxic T‐lymphocytes (CTLs) and natural killer cells. TGF‐β may be an important target in the development of novel cancer immunotherapies. In this study, we investigated the suppressive effect of TGF‐β on CTL function in vitro using OSCC cell lines and their specific CTLs. Moreover, TGFB1 mRNA expression and T‐cell infiltration in 25 OSCC tissues were examined by in situ hybridization and multifluorescence immunohistochemistry. We found that TGF‐β suppressed the function of antigen‐specific CTLs in the priming and effector phases in vitro. Additionally, TGF‐β inhibitor effectively restored the CTL function, and TGFB1 mRNA was primarily expressed in the tumor invasive front. Interestingly, we found a significant negative correlation between TGFB1 mRNA expression and the CD8⁺ T‐cell/Treg ratio and between TGFB1 mRNA expression and the Ki‐67 expression in CD8⁺ T‐cells, indicating that TGF‐β also suppressed the function of CTLs in situ. Our findings suggest that the regulation of TGF‐β function restores the immunosuppressive TME to active status and is important for developing new immunotherapeutic strategies, such as a combination of immune‐checkpoint inhibitors and TGF‐β inhibitors, for OSCCs.

Prevalence and Clinicopathologic Features of Intestinal Perforation Caused by Segmental Absence of the Intestinal Musculature in Adults

Segmental absence of the intestinal musculature (SAIM) can cause intestinal perforation in adults. However, its prevalence and clinicopathologic features have not been well-described. This study aimed to determine the prevalence of SAIM-associated perforation and characterize its clinicopathologic features. We retrospectively examined 109 cases of intestinal perforation that underwent surgical resection from January 2009 to December 2019. SAIM was defined as the complete absence of the muscularis propria without extensive inflammation and fibrinous exudation around the perforation. SAIM was the second most frequent cause of perforation (26 cases: 24%), the most frequent cause being related to diverticulitis (39 cases: 36%). The most common site was the sigmoid colon (12 cases: 46.2%). The younger group (aged below 65 y) exhibited more frequent perforation of the upper segments of the gastrointestinal tract (from the duodenum to the descending colon) than the older group (65 y and above) (P=0.0018). No patients developed recurrence. The most common gross features were well-defined circular or small punched-out lesions, and the histologic features were complete absence of the muscularis propria and absence of hemorrhage and necrosis around the area of perforation. The characteristic features of SAIM were unique and their prevalence was higher than previously reported. The precise recognition of SAIM can aid in understanding the cause of perforation and avoiding further unnecessary examinations.

The Positivity of Phosphorylated STAT3 Is a Novel Marker for Favorable Prognosis in Germinal Center B-Cell Type of Diffuse Large B-Cell Lymphoma

On the basis of immunohistochemistry, diffuse large B-cell lymphoma (DLBCL) is categorized as a germinal center B-cell (GCB) or non-GCB subtype. Recent integrated genomic analyses have highlighted the importance of the JAK-STAT3 pathway in the molecular pathogenesis of DLBCL. However, its relevance to clinical outcomes remains controversial. Therefore, we evaluated the extent of the nuclear expression of phosphorylated STAT3 (pSTAT3), a surrogate marker of signal transducer and activator of transcription 3 (STAT3) activation, by immunohistochemistry. We also analyzed the potential relationship between pSTAT3 positivity (defined as ≥40% positive neoplastic cells) and clinicopathologic characteristics in 294 patients with DLBCL. pSTAT3 was detected in 122 patients (42%), with a higher rate in the non-GCB subtype than in the GCB subtype (57% vs. 28%, P<0.001). Factors potentially activating STAT3, MYD88L265P, and Epstein-Barr virus-encoded small RNA were identified in the pSTAT3-positive non-GCB subtype, whereas the pSTAT3-positive GCB subtype often showed STAT3 mutations and lacked EZH2 mutations and the rearrangements of BCL2 and MYC. Multivariate analyses revealed that the pSTAT3-positive GCB subtype showed a favorable prognosis (HR: 0.17; 95% confidence interval, 0.04-0.7; P=0.014). These findings suggest that pSTAT3 positivity may have a unique impact on the clinicopathologic characteristics of DLBCL, making it a promising novel marker for the favorable prognosis of patients with the GCB subtype.

Primary cutaneous methotrexate-associated B-cell lymphoproliferative disorders other than EBV-positive mucocutaneous ulcer: clinical, pathological, and immunophenotypic features

Methotrexate (MTX)-associated B-cell lymphoproliferative disorders (B-LPD) may first present in the skin. Epstein-Barr virus (EBV)-positive mucocutaneous ulcer (EBVMCU) is now a well known disease listed in the 2017 World Health Organization classification. However, primary cutaneous MTX-associated B-LPD (pcMTX B-LPD), other than EBVMCU, appear to be underestimated, and their distinctiveness remains unproven. This study aimed to document the clinicopathological characteristics of nine patients with pcMTX B-LPD that were not EBVMCU to extend our understanding of this peculiar disease. The cohort included three males and six females, with a median age of 74 years (range 54-83 years). All patients were treated with MTX for RA. Of nine patients, four presented with a solitary lesion, and five had multiple lesions. Histologically, five cases showed a polymorphic pattern, and four showed a monomorphic pattern. Immunohistochemically, four cases showed positive EBER staining, and one showed positive CD5 staining. In eight cases, once pcMTX B-LPD was diagnosed, methotrexate was immediately withdrawn. All eight of these patients experienced spontaneous regression and achieved complete remission (CR), without relapse. The patient with CD5 positivity received cytotoxic chemotherapy as the initial treatment. This patient achieved a CR after the initial treatment, but eventually experienced disease relapse resulting in death. We also revealed that pcMTX B-LPD and MTX-associated EBVMCU exhibited similar biological behaviours. We concluded that most pcMTX B-LPD cases could be cured by stopping MTX treatment. We also highlighted the fact that pcMTX B-LPD and MTX-EBVMCU had overlapping features. This finding suggested that pcMTX B-LPD and MTX-EBVMCU might share an underlying mechanism.

Expression of programmed cell death ligand-1 by immune cells in the microenvironment is a favorable prognostic factor for primary diffuse large B-cell lymphoma of the central nervous system

Primary diffuse large B-cell lymphoma (DLBCL) of the central nervous system (PCNS-DLBCL) is rare. Thirty-nine patients consecutively diagnosed as having PCNS-DLBCL were analyzed to highlight the prognostic value of the expression of programmed cell death ligand-1 (PD-L1) by neoplastic cells and immune cells in the microenvironment. They were positive for CD20 in all (100%), CD5 in two (5%), CD10 in nine (23%), BCL-2 in 27 (69%), BCL-6 in 34 (87%), and MUM-1 in 37 (95%). Only one case was positive for neoplastic PD-L1, with an unexpectedly long clinical course of 92 months. The remaining 38 cases were further divided into three groups based on the percentage of PD-L1⁺ cells among microenvironmental immune cells. Cutoffs of < 5%, 5-40%, and ≥ 40% successfully stratified mean prognoses with three-year overall survival (OS) of 21%, 63%, and 100% (P = 0.009), respectively. Progression-free survival (PFS) and OS were different between the groups with and without methotrexate (MTX)-containing chemotherapy (P = 0.007 and P < 0.001, respectively). Multivariate analysis identified three independent adverse factors of OS: PD-L1 negativity (< 5%) on microenvironmental immune cells (P = 0.027), deep structure involvement (P = 0.034), and performance status (PS) 2-4 (P = 0.009). The study showed that PD-L1 expression on immune cells in the microenvironment was associated with prognosis among patients with PCNS-DLBCL.

Histiocytic and dendritic cell neoplasms: Reappraisal of a Japanese series based on t(14;18) and neoplastic PD-L1 expression

Histiocytic and dendritic cell (H/DC) neoplasms are heterogeneous, originating from myeloid- or stromal-derived cells. Multiple reports describe the cross-lineage transdifferentiation of neoplastic B cells into H/DC neoplasms. Most such cases are from Western countries, and rarely from Japan or East Asia. Here we report 17 cases of H/DC neoplasms in Japanese patients, with analysis of t(14;18) by fluorescence in situ hybridization, and of neoplastic programmed death-ligand 1 (PD-L1) expression by immunostaining (clones SP142, E1J2J, and 28-8). These 17 cases were diagnosed according to the 2017 World Health Organization (WHO) classification, and included two histiocytic sarcomas (HS), two interdigitating cell (IDC) sarcomas, one Langerhans cell sarcoma, two dendritic cell sarcomas, and 10 follicular dendritic cell (FDC) sarcomas. No case had any past history of follicular lymphoma (FL). Two cases of HS and one IDC sarcoma, all of which were myeloid-driven, were found to exhibit t(14;18). In the latter case, at 30 months after IDC sarcoma diagnosis, FL development was detected. Three (30%) FDC sarcoma cases exhibited neoplastic PD-L1 expression with all the three PD-L1 antibody clones. This is the first report of t(14;18) and neoplastic PD-L1 expression on H/DC neoplasms among Japanese patients, each of which appeared to be associated with HS and FDC sarcoma, respectively.

Nodal EBV-positive polymorphic B cell lymphoproliferative disorder with plasma cell differentiation: clinicopathological analysis of five cases

Plasma cell differentiation (PCD) is frequently observed in some entities of non-Hodgkin B cell lymphoma, including both low-grade and high-grade lymphomas. However, except for plasmablastic lymphoma and primary effusion lymphoma, EBV⁺ B cell lymphoproliferative disorder (LPD) with PCD has not been well addressed due to its rarity. We clinicopathologically examined five cases of nodal EBV⁺ polymorphic B cell LPD with PCD (PBLPD-PCD) initially diagnosed as polymorphic EBV⁺ diffuse large B cell lymphoma, not otherwise specified (DLBCL-NOS) with PCD (n = 3) and methotrexate-associated B cell LPD (MTX-associated B-LPD) (n = 2). One case had a concomitant brain lesion which was clinically diagnosed as EBV-related encephalitis. This patient received therapy with vidarabine, and both the brain lesion and the nodal EBV⁺ PBLPD-PCD lesions disappeared. Another case was characterized by Mott cell differentiation. This case was the first reported case of EBV⁺ B cell lymphoma or LPD with Mott cell differentiation. The two cases of MTX-associated B cell LPD which arose in patients with rheumatoid arthritis spontaneously regressed after MTX cessation. TCRγ and IGH PCR analysis was performed in four cases. Two cases had TCRγ rearrangements, but no IGH rearrangements. The other two cases had no rearrangements in these genes. We concluded that nodal EBV⁺ PBLPD-PCD is rare, with heterogeneous characteristics. PCR analysis revealed that nodal EBV⁺ PBLPD-PCD may have only TCR clonality and no IGH clonality. Considering the partial or complete loss of CD20 expression on the tumor cells, this result may be confusing for accurate diagnosis of EBV⁺ PBLPD-PCD, and pathologists need to be aware of this phenomenon to avoid misdiagnosis.

Synchronous clear cell renal cell carcinoma and clonal plasmacytoid cell infiltration: A case report and literature review

Recent studies of tumor microenvironments have revealed that clonal B cells reacting to tumor-derived antigens play an important role in anti-tumor immunity. We report a case of a 72-year-old Japanese man with a complaint of fever for 1 month. Computed tomography revealed a 48 mm mass in his right kidney. The patient underwent a right nephrectomy and histology revealed clear cell renal cell carcinoma (ccRCC) of Fuhrman Grade 4 with rhabdoid morphology. Focally, marked plasmacytoid cell infiltration was detected in the carcinoma. These plasmacytoid cells were immunohistochemically positive for immunoglobulin (Ig) G, and kappa light chain restriction was confirmed using mRNA in situ hybridization. Programmed death-ligand 1 (PD-L1) immunostaining and RNA in situ hybridization of transforming growth factor beta (TGF-β) revealed that both PD-L1 and TGF-β were highly expressed in the area with clonal plasmacytoid cell infiltration. The patient developed bone metastasis 3 months after surgery, and plasmacytoma was not detected during the observation period. We identified a potential link between an immunosuppressive microenvironment and clonal B cell proliferation. The latter posed a differential diagnosis problem between reactive and neoplastic clonal B cell proliferation vis-à-vis a plasmacytoma complicating carcinoma.

The highest Fuhrman and WHO/ISUP grade influences the Ki-67 labeling index of those of grades 1 and 2 in clear cell renal cell carcinoma

Nuclear grade is one of the most important prognostic factors in clear cell renal cell carcinoma (CCRCC). Although CCRCCs usually have intratumoral heterogeneity with various nuclear atypia including nucleolar prominence, it is unclear whether a similar degree of nuclear grade component demonstrates the same proliferative activity. We aimed to reveal whether the presence of a higher nuclear grade has an effect on proliferative activity among each assigned nuclear grade in CCRCCs. We enrolled 129 CCRCC patients containing at least two different nuclear grades. We separately assessed nuclear grade using the Fuhrman and World Health Organization and International Society of Urologic Pathologists (WHO/ISUP) grading systems. In addition, we selected blocks containing different nuclear grade and assessed the Ki-67 labeling index (LI) for each using a computer-based analysis system. Ki-67 LIs significantly correlated with both Fuhrman and WHO/ISUP grades (P < 0.001 and P < 0.001). Of note, the LIs among Fuhrman and WHO/ISUP grades 1 and 2 were also statistically significant according to the highest nuclear grade (P < 0.01 for both grades 1 and 2). Our data suggests that the highest nuclear grade influences the proliferative activity in tumor components regardless of the morphologically assigned nuclear grades. The exact evaluation of Ki-67 LI in CCRCC can provide a more precise information of the malignant potential.

Clinicopathological analysis of neoplastic PD-L1-positive EBV+ diffuse large B cell lymphoma, not otherwise specified, in a Japanese cohort

The programmed death 1 (PD1)/PD1 ligand (PD-L1) axis plays an important role in the pathogenesis of Epstein-Barr virus-positive diffuse large B cell lymphoma, not otherwise specified (EBV+ DLBCL, NOS). Here, we describe PD-L1 expression by EBV+ DLBCL, NOS in order to evaluate its possible contribution to the pathogenesis of this tumor. The study included 57 cases of EBV+ DLBCL, NOS. The median patient age was 69 years and 95% (n = 54) were aged > 45. Extranodal lesions were present in 39 (69%) at initial diagnosis. PD-L1 expression (mAb SP142-positive staining) was present in more than 5% of tumor cells in only six cases (11%), in clear contrast to the 77% reported in cases aged under 45 years. Among the PD-L1+ cases, three were nodal lesions. All six PD-L1+ cases progressed in the 3 years after diagnosis and four of the six patients died of the disease within 2 years. PD-L1+ cases had significantly shorter PFS (P = 0.002) and relatively short OS (P = 0.26), compared with PD-L1- cases. EBV+ DLBCL, NOS in the elderly infrequently expressed PD-L1 and had poor prognosis. PD-L1 expression in EBV+ DLBCL, NOS of the elderly sheds light on the pathogenetic role of immune senescence.

Prognostic significance of p16 expression in high-grade prostate adenocarcinoma

Management of advanced hormone-naïve prostate cancer (HNPC) is a critical public health issue. Useful prognostic markers are thus needed to select patients who will benefit from recently introduced upfront therapies. p16 expression is an adverse prognostic marker in prostate cancer. The present study aimed to determine whether p16 expression would serve as an adverse prognostic marker in advanced HNPC. A total of 79 patients diagnosed by needle biopsy with adenocarcinoma Gleason score ≥8 between 2010 and 2013 at Aichi Medical University were included in this study. The median patient age was 73 (range 52-87) years. The median follow-up was 62 months (range 2-98). Fourteen patients had p16-positive samples. Fifteen patients died from prostate cancer, 10 of whom were in the p16-positive group. p16 positivity was associated with clinical T stage (P < 0.001), presence of IDC-P (P < 0.001), distant metastasis (P < 0.001) and lymph node metastasis (P < 0.001). These results indicate that p16 expression is associated with adverse prognostic factor of prostate cancer and suggest that p16 expression may provide useful information for treatment planning and identifying suitable candidates for upfront chemotherapy or androgen receptor axis-targeted therapy.

Anaplastic variant of diffuse large B-cell lymphoma: Reappraisal as a nodal disease with sinusoidal involvement

Anaplastic variant (av) of diffuse large B-cell lymphoma (DLBCL) is morphologically defined in the 2017 World Health Organization classification, but still an enigmatic disease in its clinicopathologic distinctiveness, posing the differential diagnostic problem from gray zone lymphoma (GZL) and classic Hodgkin lymphoma (cHL). Thirty-one cases previously diagnosed as avDLBCL were reassessed. Of these, 27 (87%) and 4 (13%) were node-based and extranodal diseases, respectively. They were further reclassified into nodal avDLBCL (n = 18), nodal CD30+ DLBCL with T-cell/histiocyte-rich large B-cell lymphoma-like features (CD30+ DLBCL-THRLBCL) (n = 6), GZL with features intermediate between DLBCL and cHL (n = 3) and CD30+ extranodal DLBCL, NOS (n = 4). The nodal avDLBCL cases had a sheet-like proliferation of large cells and/or Hodgkin/Reed-Sternberg (HRS)-like cells in 12 (67%) notably with a sinusoidal pattern in 16 (89%). They showed an expression of CD20 and/or CD79a in all and CD30 in 15 of 18. All of them were negative for PD-L1 on tumor cells, although HRS-like cells showed negativity or partial loss of other B-cell markers to varying degrees. The present study highlighted the distinctiveness of the nodal avDLBCL with sinusoidal pattern, but without neoplastic PD-L1 expression, which provide refined diagnostic criteria for a more precise pathologic and clinical characterization of this disease.

Immune-checkpoint molecules on regulatory T-cells as a potential therapeutic target in head and neck squamous cell cancers

Immune-checkpoint inhibitors improve the survival of head and neck squamous cell carcinoma (HNSCC) patients. Although recent studies have demonstrated that the tumor immune microenvironment (TIME) has critical roles in immunotherapy, the precise mechanisms involved are unclear. Therefore, further investigations of TIME are required for the improvement of immunotherapy. The frequency of effector regulatory T-cells (eTregs) and the expression of immune-checkpoint molecules (ICM) on eTregs and conventional T-cells (Tconvs) both in peripheral blood lymphocytes (PBL) and tumor-infiltrating lymphocytes (TIL) from HNSCC patients were analyzed by flow cytometry and their distributions were evaluated by multi-color immunofluorescence microscopy. High frequency eTreg infiltration into HNSCC tissues was observed and high expressions of CD25, FOXP3, stimulatory-ICM (4-1BB, ICOS, OX40 and GITR) and inhibitory-ICM (programmed cell death-1 [PD-1] and cytotoxic T-lymphocyte-associated protein-4 [CTLA-4]) were found on invasive eTregs. In contrast, the expression of stimulatory-ICM on Tconvs was low and the expression of inhibitory-ICM was high. In addition, ICM-ligands (programmed cell death-1 [PD-L1], galectin-9 and CEACAM-1) were frequently expressed on cancer cells. PD-L1 and galectin-9 were also expressed on macrophages. PD-1⁺ T-cells interacted with PD-L1⁺ cancer cells or PD-L1⁺ macrophages. This suggested that in TIL, eTregs are highly activated, but Tconvs are exhausted or inactivated by eTregs and immune-checkpoint systems, and ICM and eTregs are strongly involved in the creation of an immunosuppressive environment in HNSCC tissues. These suggested eTreg targeting drugs are expected to be a combination partner with immune-checkpoint inhibitors that will improve immunotherapy of HNSCC.

PD-L1 expression on tumor or stromal cells of nodal cytotoxic T-cell lymphoma: A clinicopathological study of 50 cases

Inhibitors of programmed cell‐death 1 (PD‐1) and programmed cell‐death ligand 1 (PD‐L1) have revolutionized cancer therapy. Nodal cytotoxic T‐cell lymphoma (CTL) is characterized by a poorer prognosis compared to nodal non‐CTLs. Here we investigated PD‐L1 expression in 50 nodal CTL patients, with and without EBV association (25 of each). We identified seven patients (14%) with neoplastic PD‐L1 (nPD‐L1) expression on tumor cells, including three males and four females, with a median age of 66 years. One of the seven cases was TCRαβ type, three were TCRγδ type and three were TCR‐silent type. Six of the seven cases exhibited a lethal clinical course despite multi‐agent chemotherapy, of whom four patients died within one year of diagnosis. Morphological findings were uniform, with six cases showing centroblastoid appearance. Among nPD‐L1⁺ cases, two of three examined had structural variations of PD‐L1 disrupting 3′‐UTR region. Notably, all of the TCRγδ‐type nodal CTL cases showed nPD‐L1 or miPD‐L1 positivity (3 and 10 cases, respectively). TCRγδ‐type cases comprised 42% of nPD‐L1⁺ cases (P = 0.043 vs. PD‐L1⁻), and 35% of miPD‐L1⁺ cases (P = 0.037 vs. PD‐L1⁻). The results indicate that PD‐L1⁺ nodal CTL cases, especially of the TCRγδ type, are potential candidates for anti‐PD‐1/PD‐L1 therapies.

PD-L1 (SP142) expression in neoplastic cells predicts a poor prognosis for patients with intravascular large B-cell lymphoma treated with rituximab-based multi-agent chemotherapy

Background

Intravascular large B‐cell lymphoma (IVLBCL) is a rare form of diffuse large B‐cell lymphoma (DLBCL) arising in extranodal sites. PD‐L1 expression of tumor cells has been reported in IVLBCL cells, but its clinicopathological relevance remains to be elucidated.

Aims

This study was aimed to reveal the characteristics of PD‐L1⁺ IVLBCL.

Methods and results

Neoplastic PD‐L1 expression was examined in 34 cases of IVLBCL and clinicopathological characteristics between patients with PD‐L1⁺ and PD‐L1⁻ IVLBCL were compared. We assessed PD‐L1 expression with SP142 antibody. Twelve (35%) of 34 cases showed positivity for PD‐L1. The PD‐L1⁺ group had significantly lower survival rates compared to the PD‐L1⁻ group. The PD‐L1⁺ IVLBCL group also had a significantly lower age distribution and a lower frequency of patients older than 60 years compared to the PD‐L1⁻ group. Very recently, we speculate that there is possible link between PD‐L1⁺ IVLBCL and PD‐L1⁺ extranodal DLBCL‐NOS (eDLBCL) because features of the two groups showed overlapping. Therefore, we compared the clinicopathological characteristics of the PD‐L1⁺ IVLBCL and PD‐L1⁺ eDLBCL. There were no significant differences in clinicopathological parameters and prognosis.

Conclusion

The worse prognosis of the PD‐L1⁺ group might be caused by immune evasion mechanisms, which are linked to PD‐L1 expression. Therefore, PD‐L1⁺ IVLBCL cases might be regarded as good candidates for targeted immunotherapy. We also highlighted the overlapping features of PD‐L1⁺ IVLBCL and PD‐L1⁺ eDLBCL. This result suggests that they should be regarded as one entity, immune evasion‐related extranodal large B‐cell lymphoma.

Age-related EBV-associated B-cell lymphoproliferative disorders and other EBV + lymphoproliferative diseases: New insights into immune escape and immunodeficiency through staining with anti-PD-L1 antibody clone SP142

Epstein-Barr virus (EBV) is prevalent among healthy individuals, and is implicated in numerous reactive and neoplastic processes in the immune system. The authors originally identified a series of senile or age-related EBV-associated B-cell lymphoproliferative disorders (LPD) bearing a resemblance to immunodeficiency-associated ones. These LPDs may be associated with immune senescence and are now incorporated into the revised 4th edition of 2017 WHO lymphoma classification as EBV-positive (EBV+) diffuse large B-cell lymphoma (DLBCL), not otherwise specified (NOS). These EBV+ B-cells often have a Hodgkin/Reed-Sternberg (HRS)-like appearance and are shared beyond the diagnostic categories of mature B-cell neoplasms, mature T-cell neoplasms, classic Hodgkin lymphoma, and immunodeficiency-associated LPD. In addition, peculiar new diseases, such as EBV+ mucocutaneous ulcer and EBV+ DLBCL affecting the young, were recognized. On the other hand, lymphoma classification is now evolving in accord with deeper understanding of the biology of programmed death ligand 1 (PD-L1). Assessing PD-L1 positivity by staining with the anti-PD-L1 monoclonal antibody SP142 provides new insight by discriminating between immune evasion and senescence or immunodeficiency. The aim of the present review is to briefly summarize the diagnostic use of immunostaining with SP142 in malignant lymphomas and/or LPDs that feature tumor and nonmalignant large B-cells harboring EBV.

Immunohistochemical Assessment of the Diagnostic Utility of PD-L1 (Clone SP142) for Methotrexate-Associated Lymphoproliferative Disorders With an Emphasis of Neoplastic PD-L1 (Clone SP142)-Positive Classic Hodgkin Lymphoma Type

OBJECTIVES

We describe results of programmed death ligand 1 (PD-L1) immunohistochemical assessment in methotrexate (MTX)-associated lymphoproliferative disorders (LPDs) and highlight the characteristics of classic Hodgkin lymphoma (CHL) type MTX-LPD.

METHODS

Fifty cases of MTX-LPD, including CHL type (n = 9), diffuse large B-cell lymphoma type (n = 15), and polymorphic B-cell LPD (n = 21), were investigated.

RESULTS

Staining with anti-PD-L1 clone SP142 was exclusively found in CHL type (89%) but not in the others. Cases of CHL type MTX-LPD involved nodal disease and were associated with Epstein-Barr virus. They were histopathologically characterized by a vaguely nodular pattern, predominance of mononuclear cells, and strong expression of at least one pan-B-cell marker. Their clinical course was variable, with spontaneous regression in 5 patients, relapse in 2, and a fatal course in 1.

CONCLUSIONS

The PD-L1 (clone SP142) workup aids the diagnostic approach to patients with MTX-LPD. CHL type MTX-LPD appears to represent a unique morphologic variant of CHL.

Prospective evaluation of 25-gauge Franseen needles for endoscopic ultrasound-guided fine-needle biopsy of solid pancreatic masses

Background and study aims  The ideal puncture needle for endoscopic ultrasound (EUS)-guided sampling is maneuverable and easy to puncture with, and can obtain sufficient material in almost one pass. The novel 25-gauge Franseen needle may provide a good balance between maneuverability and sample yield. Patients and methods  Between July 2017 and December 2018, 116 patients with solid pancreatic masses were prospectively enrolled and investigated. We evaluated the diagnostic yield associated with using the 25-gauge Franseen needle for EUS-guided sampling of pancreatic masses. Results  The technical success rate was 100 % (116/116). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for malignancy were 98 % (105/107), 100 % (9/9), 100 % (105/105), 82 % (9/11), and 98 % (114/116), respectively. Cumulative sensitivities for malignancy were 87 % (93/107) on pass 1, 97 % (104/107) on pass 2, and 98 % (105/107) on pass 3, respectively, with no increase in sensitivity after 4 or more. An adequate specimen for histological assessment was obtained in 79 % (92/116) of cases. Multivariate logistic analyses showed that lesion size smaller than 13 mm was a risk factor for failure of obtaining an adequate specimen for histological assessment ( P  = 0.010) Conclusions  The novel 25-gauge Franseen needle showed excellent diagnostic yield for solid pancreatic masses. However, its ability to obtain an adequate specimen for histological assessment may still be insufficient, especially when dealing with small lesions.

Diagnostic utility of programmed cell death ligand 1 (clone SP142) in mediastinal composite lymphoma: A report of two cases

Composite lymphoma is a well-known diagnostic entity exhibiting the synchronous occurrence of two or more distinct types of lymphomas in the same specimen. Here we report two patients, a 14-year-old female (Case 1) and a 45-year-old male (Case 2), with mediastinal composite lymphoma, comprising nodular sclerosis classic Hodgkin lymphoma (NSCHL) and primary mediastinal large B-cell lymphoma (PMBL). Both patients had a mediastinal mass, and manifested two different histologic components in the same biopsy, one characteristic of NSCHL and the other PMBL. The NSCHL areas included Hodgkin and Reed-Sternberg (HRS) cells with typical immunophenotypic features (CD30-positive and CD20-negative), whereas the sheets of large tumor cells characteristic of PMBL were strongly and uniformly CD20-positive. Interestingly, although both cases showed neoplastic PD-L1 (nPD-L1) positivity on the HRS cells of NSCHL, they differed regarding nPD-L1 expression on the PMBL tumor cells. In Case 1, the nPD-L1-negative PMBL component was anatomically situated outside the NSCHL lesion. On the other hand, in Case 2, the nPD-L1-positive PMBL component was characterized by transitional or continuous areas with the NSCHL component. These findings suggested that nPD-L1 expression may define two subtypes of PMBL that are more similar to or distinct from classic Hodgkin lymphoma.

Syncytial variant of classic Hodgkin lymphoma: Four cases diagnosed with the aid of CD274/programmed cell death ligand 1 immunohistochemistry

Although several reports have highlighted neoplastic PD-L1 (nPD-L1) expression in classic Hodgkin lymphoma (CHL), some have addressed associations between its expression and detailed histopathologic features. Here we describe four cases of syncytial variant of CHL (SV-CHL), with and without Epstein-Barr virus (EBV) association, and highlight the diagnostic utility of PD-L1 (clone SP142) immunohistochemistry. The patients were a 61-year-old male, 45-year-old male, 85-year-old female, and 89-year-old female. All presented with cervical or axillary lymphadenopathy, which on biopsy had the established histopathologic features of SV-CHL with a biphasic pattern of cohesive sheets of large tumor cells and typically scattered distribution of Hodgkin and Reed-Stenberg (HRS) cells. These tumor cells showed identical immunophenotypic findings for CD15, CD30, Fascin, PAX5, OCT2, BOB1 and EBV harboring, regardless of location. The exception was absent or decreased expression of nPD-L1 from tumor cells in the confluent sheets, contrasting with HRS cell positivity in typical areas of CHL. These findings offer the first suggestion of possible downregulation of nPD-L1 expression in association with the histopathologic progression of CHL. The results may be relevant for recognizing 'confluent' sheets in the diagnostic workup for SV-CHL.

EBV status has prognostic implication among young patients with angioimmunoblastic T-cell lymphoma

Epstein‐Barr virus (EBV)‐positive B cells have been detected in 66%‐86% of patients with angioimmunoblastic T‐cell lymphoma (AITL). However, it remains controversial whether EBV status has an impact on the survival of patients with AITL. In this study, we aimed to reevaluate the impact of EBV on the clinicopathological characteristics of AITL. In particular, we focused on the impact of EBV in younger patients with AITL. In total, 270 cases of AITL were studied. Epstein‐Barr virus‐positive B cells were detected in 191 (71%) cases (EBER⁺ group). Among the patients who received anthracycline‐based therapy, the EBER status did not affect the overall survival (OS) or progression‐free survival (PFS). In the younger group of AITL (≤60 years), PFS was significantly worse in the EBER⁻ group compared to the EBER⁺ group (P = .0013). Furthermore, the multivariate analysis identified EBER‐negative status, thrombocytopenia, and elevated serum IgA level as significant adverse prognostic factors for PFS (P < .001, P < .001, and P = .002). Based on these findings, we constructed new prognostic model for the younger group, based on three adverse factors. We classified the patients into two risk groups: low risk (no or 1 adverse factor) and high risk (2 or 3 adverse factors). This new model for younger patients with AITL showed that both OS and PFS were significantly related to the level of risk (P < .0001). In summary, this study showed that, among younger patients with AITL, an EBER⁺ status significantly improved prognosis compared to an EBER⁻ status. Our new prognostic model should be applicable to younger patients with AITL.

Methotrexate-associated lymphoproliferative disorders of T-cell phenotype: clinicopathological analysis of 28 cases

Methotrexate-associated lymphoproliferative disorders are categorized as "other immunodeficiency-associated lymphoproliferative disorders in the WHO classification. Methotrexate-associated lymphoproliferative disorder is mainly a B-cell lymphoproliferative disorders or Hodgkin lymphoma type, whereas T-cell lymphoproliferative disorders are relatively rare (4-8%). Only a small number of methotrexate-associated T-cell lymphoproliferative disorders have been detailed thus far. Because of the rarity, methotrexate-associated T-cell lymphoproliferative disorder has not been well studied and its clinicopathological characteristics are unknown. A total of 28 cases of methotrexate-associated T-cell lymphoproliferative disorders were retrospectively analyzed. Histologically and immunohistochemically, they were divided into three main types: angioimmunoblastic T-cell lymphoma (n = 19), peripheral T-cell lymphoma, NOS (n = 6), and CD8⁺ cytotoxic T-cell lymphoma (n = 3). Among the 28 cases, only one CD8⁺ cytotoxic T-cell lymphoma case was Epstein-Barr virus-positive. The other 27 cases were negative for Epstein-Barr virus on tumor cells, but scattered Epstein-Barr virus-infected B-cells were detected in 24 cases (89%), implying the reactivation of Epstein-Barr virus caused by immunodeficient status of the patients. After the diagnosis of methotrexate-associated T-cell lymphoproliferative disorder, methotrexate was immediately withdrawn in 26 cases. Twenty (77%) cases presented with spontaneous regression. Compared to methotrexate-associated B-cell lymphoproliferative disorder, patients with methotrexate-associated T-cell lymphoproliferative disorder had a significantly higher proportion of males (p = 0.035) and presence of B-symptoms (p = 0.036), and lower proportion of Epstein-Barr virus⁺ tumor cells (p < 0.001). Although the difference was not significant, the methotrexate-associated T-cell lymphoproliferative disorder also had more frequent spontaneous regression (p = 0.061). In conclusion, methotrexate-associated T-cell lymphoproliferative disorder was divided into three main types: angioimmunoblastic T-cell lymphoma, peripheral T-cell lymphoma, NOS, and CD8⁺ cytotoxic T-cell lymphoma. Angioimmunoblastic T-cell lymphoma was the most common type. Methotrexate-associated T-cell lymphoproliferative disorder was characterized by a high rate of spontaneous regression after methotrexate cessation. Epstein-Barr virus positivity was relatively rare in methotrexate-associated T-cell lymphoproliferative disorder, significantly less frequent than methotrexate-associated B-cell lymphoproliferative disorder, suggesting different pathogenesis.

EBV-positive mucocutaneous ulcer arising in rheumatoid arthritis patients treated with methotrexate: Single center series of nine cases

Methotrexate (MTX) is currently used as first-line anchor drug for rheumatoid arthritis (RA). Therefore, the number of MTX-associated lymphoproliferative disorders, including Epstein-Barr virus-positive mucocutaneous ulcer (EBVMCU), has increased. Some aspects of MTX-associated EBVMCU (MTX-EBVMCU), particularly clinical behavior and treatment for RA after MTX cessation, have not been well described. Herein, we report nine cases of MTX-EBVMCU with clinical information regarding RA. Seven of nine patients showed spontaneous regression (SR) after immunosuppressive (IS) cessation. The other two required cytotoxic chemotherapy. Eventually, all achieved complete remission. No patients experienced EBVMCU relapse. Eight patients had RA flare after IS cessation. To control the RA activity, rituximab was administered to three patients. The remaining patients were treated by other agents. Regarding the RA activity, all were in the status of low disease activity or clinical remission. In conclusion, MTX-associated EBVMCU has an indolent clinical course and SR after IS cessation can be expected. After the withdrawal of MTX, the majority of patients experience RA flare and required treatment. In our series, RA was well controlled without reinitiating MTX. Therefore, to prevent the EBVMCU relapse, it might be advisable to avoid MTX reintroduction, and rituximab might be the more preferable agent for RA treatment.

Immune evasion-related extranodal large B-cell lymphoma: A report of six patients with neoplastic PD-L1-positive extranodal diffuse large B-cell lymphoma

We identified six patients with Epstein-Barr virus (EBV)-negative extranodal diffuse large B-cell lymphoma (DLBCL) and immunohistochemical expression of PD-L1 on their tumor cells by examining 283 DLBCL cases with the PD-L1 SP142 clone between 2015 and 2017. They consisted of two men and four women with a median age of 71 years, and were examined in an autopsy (n = 1) and biopsies from the adrenal gland (n = 2), skin (n = 1), pelvic cavity (n = 1), and kidney (n = 1). All showed a monomorphic population of large transformed B-cells leading to diagnoses of DLBCL with two intravascular large B-cell lymphoma (IVLBCL) and one de novo CD5+ type and were featured by an invariable immunephenotype: CD3-, CD20+, BCL-2+, and MUM1+. In addition, CD5 and CD10 were each detected in one case. All cases expressed PD-L1 on >10% to >90% of tumor cells, which was confirmed with two other PD-L1 antibodies (E1J2J and 28-8). Three untreated patients had a rapid, lethal clinical course within 7 months after diagnosis; while, the remaining three achieved complete remission after treatment and were alive at the last follow-up. We suggest immune evasion-related extranodal large B-cell lymphoma should be recognized beyond the currently identified entities of IVLBCL and de novo CD5+ DLBCL.

Immunohistochemical assessment of the diagnostic utility of PD-L1: a preliminary analysis of anti-PD-L1 antibody (SP142) for lymphoproliferative diseases with tumour and non-malignant Hodgkin-Reed-Sternberg (HRS)-like cells

AIMS

The programmed death 1 (PD1)/PD1 ligand (PD-L1) axis plays an important role in tumour cells escape from immune control. PD-L1 immunohistochemistry is a useful predictor of immunotherapy response, but is still not used widely in the diagnostic setting. Here we describe results using PD-L1 immunohistochemistry during routine diagnostics in lymphoma.

METHODS AND RESULTS

Ninety-one lymphoproliferative disease cases sharing tumour and non-malignant Hodgkin-Reed-Sternberg (HRS)-like cells with and without Epstein-Barr virus (EBV) association were investigated by immunohistochemistry for PD-L1 (clone SP142). PD-L1 expression was present in more than 5% of tumour or non-malignant HRS-like cells in 100% of EBV⁺ classical (C) Hodgkin lymphoma (HL) (n = 10) and EBV-negative nodular sclerosis CHL (n = 8); 40% of EBV⁺ diffuse large B cell lymphoma, not otherwise specified (DLBCL-NOS) (n = 20); and 4% of nodal peripheral T cell lymphoma of follicular helper T cell type (PTCL-TFH) (n = 22). In contrast, nodular lymphocyte-predominant HL (n = 4), lymphocyte-rich CHL (n = 6), EBV⁺ hyperplasia (n = 8), plasmablastic lymphoma (n = 3) and anaplastic lymphoma kinase-negative anaplastic large cell lymphoma (n = 5) seldom exhibited PD-L1 in their large cells. Assessing PD-L1 positivity in tumour and non-malignant large cells was helpful in differentiating between CHL versus nodal PTCL-TFH (P < 0.0001) or EBV⁺ DLBCL-NOS (P = 0.0052) and between EBV⁺ DLBCL-NOS versus nodal PTCL-TFH (P = 0.0052), with PD-L1 expression indicating the first diagnosis in each of those sets.

CONCLUSION

Immunohistochemical evaluation of PD-L1 expression in tumour and non-malignant HRS-like large cells may be useful for assessing either immune escape or immunodeficiency in their pathogenesis.

Heterogeneous impact of smoking on major salivary gland cancer according to histopathological subtype: A case-control study

BACKGROUND

Major salivary gland cancers (M-SGCs) are rare, and have distinct heterogeneous histopathological subtypes. To the authors' knowledge, no consistent evidence of an association between cigarette smoking and the risk of M-SGCs has appeared to date. Furthermore, evidence of potential heterogeneity in the impact of smoking on histopathological subtypes is scarce, despite the fact that the histopathological subtypes of M-SGC exhibit different genetic features.

METHODS

The authors conducted a case-control study to investigate the association between smoking and M-SGC by histopathological subtype. Cases were 81 patients with M-SGCs and the controls were 810 age-matched and sex-matched first-visit outpatients without cancer treated at Aichi Cancer Center Hospital from 1988 to 2005. Odds ratios (OR) and 95% confidence intervals (95% CI) were assessed by conditional logistic regression analysis with adjustment for potential confounders.

RESULTS

Smoking was found to be associated with a significantly increased risk of M-SGC overall, with an OR of 3.45 (95% CI, 1.58-7.51; P =.001) for heavy smokers compared with never-smokers. A significant dose-response relationship was observed (P for trend, .001). When stratified by histological subtype, no obvious impact of smoking was observed among patients with mucoepidermoid carcinoma (MEC). In contrast, smoking demonstrated a significantly increased risk of M-SGCs other than MEC, with an OR of 5.15 (95% CI, 2.06-12.87; P<.001) for heavy smokers compared with never-smokers. The authors observed possible heterogeneity with regard to the impact of smoking on risk between MEC and M-SGCs other than MEC (P for heterogeneity, .052).

CONCLUSIONS

The results of the current study demonstrate a significant positive association between cigarette smoking and the risk of M-SGC overall. However, the impact of smoking appeared to be limited to M-SGCs other than MEC. Cancer 2018;124:118-24. © 2017 American Cancer Society.

Stability of cervical esophagogastrostomy via hand-sewn anastomosis after esophagectomy for esophageal cancer

The aim of the present study is to evaluate the outcome of hand-sewn esophagogastric anastomosis during radical esophagectomy for esophageal cancer. The outcomes of 467 consecutive esophageal cancer patients who underwent cervical esophagogastric anastomosis using interrupted and double-layered sutures after radical esophagectomy via right thoracotomy or thoracoscopic surgery were retrospectively reviewed. Anastomotic leakage, including conduit necrosis, occurred in 11 of 467 patients (2.4%); 7 of 11 (63.6%) cases experienced only minor leakage, whereas the other four (36.4%) patients had major leakage that required surgical or radiologic intervention, including two patients of conduit necrosis. Anastomotic leakages were more frequently observed after retrosternal reconstruction compared with the posterior mediastinal route (P < 0.0001). The median time to healing of leakage was 40 days (range: 14-97 days). Two patients (2/467, 0.4%) died in the hospital due to sepsis caused by the leakage and conduit necrosis. Twelve patients (2.6%) developed anastomotic stenosis, which was improved by dilatation in all patients. Hand-sewn cervical esophagogastric anastomosis is a stable and highly safe method of radical esophagectomy for esophageal cancer.

Synergistic activity of Card11 mutant and Bcl6 in the development of diffuse large B-cell lymphoma in a mouse model

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of malignant lymphoma; it derives from germinal center B cells. Although DLBCL harbors many genetic alterations, synergistic roles between such alterations in the development of lymphoma are largely undefined. We previously established a mouse model of lymphoma by transplanting gene-transduced germinal center B cells into mice. Here, we chose one of the frequently mutated genes in DLBCL, Card11 mutant, to explore its possible synergy with other genes, using our lymphoma model. Given that BCL6 and BCL2 expression and/or function are often deregulated in human lymphoma, we examined the possible synergy between Card11, Bcl6, and Bcl2. Germinal center B cells were induced in vitro, transduced with Card11 mutant, Bcl6, and Bcl2, and transplanted. Mice rapidly developed lymphomas, with exogenously transduced Bcl2 being dispensable. Although some mice developed lymphoma in the absence of transduced Bcl6, the absence was compensated by elevated expression of endogenous Bcl6. Additionally, the synergy between Card11 mutant and Bcl6 in the development of lymphoma was confirmed by the fact that the combination of Card11 mutant and Bcl6 caused lymphoma or death significantly earlier and with higher penetrance than Card11 mutant or Bcl6 alone. Lymphoma cells expressed interferon regulatory factor 4 and PR domain 1, indicating their differentiation toward plasmablasts, which characterize activated B cell-like DLBCL that represents a clinically aggressive subtype in humans. Thus, our mouse model provides a versatile tool for studying the synergistic roles of altered genes underlying lymphoma development.