Pathology and biology of peripheral T-cell lymphomas

Role of cytokine in malignant T-cell metabolism and subsequent alternation in T-cell tumor microenvironment

T cells are an important component of adaptive immunity and T-cell-derived lymphomas are very complex due to many functional sub-types and functional elasticity of T-cells. As with other tumors, tissues specific factors are crucial in the development of T-cell lymphomas. In addition to neoplastic cells, T- cell lymphomas consist of a tumor micro-environment composed of normal cells and stroma. Numerous studies established the qualitative and quantitative differences between the tumor microenvironment and normal cell surroundings. Interaction between the various component of the tumor microenvironment is crucial since tumor cells can change the microenvironment and vice versa. In normal T-cell development, T-cells must respond to various stimulants deferentially and during these courses of adaptation. T-cells undergo various metabolic alterations. From the stage of quiescence to attention of fully active form T-cells undergoes various stage in terms of metabolic activity. Predominantly quiescent T-cells have ATP-generating metabolism while during the proliferative stage, their metabolism tilted towards the growth-promoting pathways. In addition to this, a functionally different subset of T-cells requires to activate the different metabolic pathways, and consequently, this regulation of the metabolic pathway control activation and function of T-cells. So, it is obvious that dynamic, and well-regulated metabolic pathways are important for the normal functioning of T-cells and their interaction with the microenvironment. There are various cell signaling mechanisms of metabolism are involved in this regulation and more and more studies have suggested the involvement of additional signaling in the development of the overall metabolic phenotype of T cells. These important signaling mediators include cytokines and hormones. The impact and role of these mediators especially the cytokines on the interplay between T-cell metabolism and the interaction of T-cells with their micro-environments in the context of T-cells lymphomas are discussed in this review article.

Nodal peripheral T-cell lymphoma: Chemotherapy-free management, are we there yet?

Peripheral T-cell lymphomas (PTCLs) are a diverse and uncommon type of lymphoid malignancies with a dismal prognosis. Recent advances in genomic studies have shown recurring mutations that are changing our knowledge of the disease's molecular genetics and pathogenesis. As such, new targeted therapies and treatments to improve disease outcomes are currently being explored. In this review, we discussed the current understanding of the nodal PTCL biology with potential therapeutic implications and gave our insights on the promising novel therapies that are currently under study such as immunotherapy, chimeric antigen receptor T-cell therapy, and oncolytic virotherapy.

Primary soft tissue sarcoma: stage IV extranodal T-cell non-Hodgkin's lymphoma

Non-Hodgkin's lymphoma (NHL) presenting as a soft tissue sarcoma is rare, occurring at a rate of 0.11%. Peripheral T-cell lymphomas comprise 4% of all NHLs. We report the case of a 49-year-old Caucasian man who presented with a mass in the medial aspect of the thigh. Ultrasound showed a complex subcutaneous mass. MRI demonstrated a superficial complex skeletal mass affecting the sartorius muscle with other lesions involving the femur and the gluteus maximus. Positron emission tomography-computed tomography (PET-CT) showed diffuse pulmonary metastases with no involvement of nodes, liver, spleen with high suspicion of advanced sarcoma. Core biopsy revealed a T-cell NHL, and staining was positive for anaplastic lymphoma kinase. The patient received six cycles of cyclophosphamide, doxorubicin, vincristine, etoposide and prednisone. Repeat PET-CT showed reduction in the mass, with no fluorodeoxyglucose-avid uptake. Latest MRI showed near-normal intensity. Further PET-CTs determine disease remission or progression.

Comprehensive analysis of peripheral T-cell and natural killer/T-cell lymphoma in Asian patients: A multinational, multicenter, prospective registry study in Asia

Background

Peripheral T-cell lymphomas (PTCLs) are uncommon and their frequency is regionally heterogeneous. Several studies have been conducted to evaluate the clinical features and treatment outcomes of this disease entity, but the majority of these were conducted in limited areas, making it difficult to comprehensively analyze their relative frequency and clinical features. Furthermore, no consensus treatment for PTCLs has been established. Therefore, we conducted an Asia-specific study to understand the relative frequency of PTCLs and assess treatments and their outcomes in Asian patients.

Methods

We performed a multinational, multicenter, prospective registry of adult patients with PTCLs that was named as the International Cooperative non-Hodgkin T-cell lymphoma prospective registry study where thirty-two institutes from six Asian countries and territories (Korea, China, Taiwan, Singapore, Malaysia, and Indonesia) participated.

Findings

A total of 486 patients were registered between April 2016 and February 2019, and more than a half of patients (57%) had stage III or IV. Extranodal natural killer (NK)/T- cell lymphoma was the most common subtype (n = 139,28.6%), followed by angioimmunoblastic T-cell lymphoma (AITL, n = 120,24.7%), PTCL-not otherwise specified (PTCL-NOS, n = 101,20.8%), ALK-positive anaplastic large cell lymphoma (ALCL, n = 34,6.9%), and ALK-negative ALCL (n = 30,6.2%). The median progression-free survival (PFS) and overall survival (OS) were 21.1 months (95% CI,10.6-31.6) and 83.6 months (95% CI, 56.7-110.5), respectively. Upfront use of combined treatment with chemotherapy and radiotherapy showed better PFS than chemotherapy alone in localized ENKTL whereas consolidation with upfront autologous stem cell transplantation (SCT) provided longer PFS in advance stage ENKTL. In patients with PTCLs other than ENKTL, anthracycline-containing chemotherapies were widely used, but the outcome of those regimens was not satisfactory, and upfront autologous SCT was not significantly associated with survival benefit, either. The treatment outcome of salvage chemotherapy was disappointing, and none of the salvage strategies showed superiority to one another.

Interpretation

This multinational, multicenter study identified the relative frequency of each subtype of PTCLs across Asian countries, and the survival outcomes according to the therapeutic strategies currently used.

Funding

Samsung Biomedical Research Institute.

Advances in Frontline Management of Peripheral T-cell Lymphoma

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of lymphomas that are frequently associated with a poor prognosis. For many decades, the standard-of-care has been CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone)-based therapy, but it is well-recognized that survival outcomes are unsatisfactory, especially when compared with B-cell lymphomas. Major recent advances in cancer diagnosis and management have the potential to significantly improve PTCL outcomes. These include: (1) improved diagnostic techniques that incorporate molecular genetic data to further refine diagnosis and subtyping; (2) the development of novel agents; and (3) improved monitoring modalities, such as ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography scans and circulating tumor DNA. In this review, we aim to explore these 3 advances in the context of frontline management of PTCL.

High intratumoural galectin-1 expression predicts adverse outcome in ALK- ALCL and CD30+ PTCL-NOS

Galectin-1 (Gal-1) has been associated with adverse prognosis in several cancers including lymphoma entities with CD30 expression. However, Gal-1 expression has not been systematically assessed in peripheral T-cell lymphomas (PTCL). Specimens from 169 nodal PTCL were assessed for intratumoural Gal-1 expression by immunohistochemistry. Overall survival (OS) in groups exhibiting high and low Gal-1 expression was compared in the cohort and in a subset analysis of CD30-positive PTCL only. Gal-1 expression was also correlated with biomarkers of the tumour microenvironment. No significant difference in OS based on Gal-1 expression was observed in the entire PTCL cohort. However, in the CD30-positive cohort, patients with high Gal-1 levels had significantly poorer outcome (5 years OS 10%, 95% confidence interval CI, 1-36) than their low Gal-1 counterparts (5 years OS 48%, 95% CI, 30-64, P = .021). In univariate analyses age 60 or younger, non-elevated lactate dehydrogenase (LDH), and performance score less than 2 correlated with superior survival but high Gal-1 expression significantly predicted adverse outcome at both univariate (HR 2.5, 95% CI, 1.1-5.7, P = .026) and multivariate levels (HR 3.2, 95% CI, 1.2-8.5, P = .017). Tumours with high Gal-1 had few cytotoxic T cells in the tumour microenvironment. High intratumoural Gal-1 expression before therapeutic intervention correlates with adverse outcome in nodal CD30⁺ , ALK^- PTCL patients.

Nasal-type extranodal natural killer/T-cell lymphoma presenting with a mass on the buttock: A case report

RATIONALE

Nasal-type extranodal natural killer (NK)/T-cell lymphoma is a highly unusual disease with no standard curative managements yet. Our focus is to emphasize a very rare case of nasal-type extranodal NK/T-cell lymphoma with onset of the mass on the buttock successfully operated by combination of surgical excision together with chemotherapy. The management of these unique cases is of great clinical guiding significance.

PATIENT CONCERNS

A 20-year-old woman presented with a 2-month history of continuous and progressive severe pain on her left buttock. Since December 2017, the patient developed nasal congestion, accompanied with mild pain in the left eye, and new subcutaneous nodules on both cheeks.

DIAGNOSIS

Postoperative pathology confirmed the diagnosis of extranodal NK/T cell lymphoma. This is an extremely rare presentation of nasal-type NK/T-cell lymphoma.

INTERVENTIONS

The patient underwent enlarged resection of the tumor on the buttock. After the diagnosis of extranodal NK/T-cell lymphoma was established, the patient received chemotherapy and autologous hematopoietic stem cell transplantation.

OUTCOMES

The patient's symptoms improved significantly after the surgery, and the postoperative period was uneventful at the 1-year follow-up visit. There were no complications associated with the operation and adjuvant therapies during the follow-up period.

LESSONS

Taken together, the lesion's clinical features, imaging results, and pathological characteristics are unique. Extranodal NK/T-cell lymphoma, although rare, should be part of the differential diagnosis when the patient presents with the mass on the buttock. We recommend enlarged excision of the extranodal lymphoma. Combined of surgical excision of the extranodal lymphoma, chemotherapy and autologous hematopoietic stem cell transplantation are good choice for proper treatment.

Proteomic profiling identifies outcome-predictive markers in patients with peripheral T-cell lymphoma, not otherwise specified

Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) constitutes a heterogeneous category of lymphomas, which do not fit into any of the specifically defined T-cell lymphoma entities. Both the pathogenesis and tumor biology in PTCL-NOS are poorly understood. Protein expression in pretherapeutic PTCL-NOS tumors was analyzed by proteomics. Differentially expressed proteins were compared in 3 distinct scenarios: (A) PTCL-NOS tumor tissue (n = 18) vs benign lymphoid tissue (n = 8), (B) clusters defined by principal component analysis (PCA), and (C) tumors from patients with chemosensitive vs refractory PTCL-NOS. Selected differentially expressed proteins identified by proteomics were correlated with clinico-pathological features and outcome in a larger cohort of patients with PTCL-NOS (n = 87) by immunohistochemistry (IHC). Most proteins with altered expression were identified comparing PTCL-NOS vs benign lymphoid tissue. PCA of the protein profile defined 3 distinct clusters. All benign samples clustered together, whereas PTCL-NOS tumors separated into 2 clusters with different patient overall survival rates (P = .001). Differentially expressed proteins reflected large biological diversity among PTCL-NOS, particularly associated with alterations of "immunological" pathways. The 2 PTCL-NOS subclusters defined by PCA showed disturbance of "stress-related" and "protein metabolic" pathways. α-Enolase 1 (ENO1) was found differentially expressed in all 3 analyses, and high intratumoral ENO1 expression evaluated by IHC correlated with poor outcome (hazard ratio, 2.09; 95% confidence interval, 1.17-3.73; P = .013). High expression of triosephosphate isomerase (TPI1) also showed a tendency to correlate with poor survival (P = .057). In conclusion, proteomic profiling of PTCL-NOS provided evidence of markedly altered protein expression and identified ENO1 as a novel potential prognostic marker.

Multiple Ways to Detect IDH2 Mutations in Angioimmunoblastic T-Cell Lymphoma from Immunohistochemistry to Next-Generation Sequencing

Angioimmunoblastic T-cell lymphoma (AITL) is a peripheral T-cell lymphoma associated with chemoresistance and a poor prognosis. Various nonsynonymous mutations in the R172 residue of IDH2 are present in 20% to 30% of AITL patients. In addition to their diagnostic value, these mutations are potentially targetable, especially by isocitrate dehydrogenase (IDH) 2 inhibitor, and therefore their identification in a routine setting is clinically relevant. However, in AITL, the neoplastic cells may be scarce, making the identification of molecular anomalies difficult. We evaluated the diagnostic value of different methods to detect IDH2 mutations in formalin-fixed, paraffin-embedded tumor samples. Immunohistochemistry with an anti-IDH2 R172K antibody, Sanger sequencing, high-resolution melting PCR, allele-specific real-time quantitative PCR, and next-generation sequencing (NGS) were applied to biopsy specimens from 42 AITL patients. We demonstrate that the IDH2 R172K antibody is specific to this amino acid substitution and highly sensitive for the detection of the IDH2^R172K variant, the most frequent substitution in this disease. In our study, NGS and allele-specific real-time quantitative PCR displayed a good sensitivity, detecting 96% and 92% of IDH2 mutations, respectively, in contrast to Sanger sequencing and high-resolution melting PCR, which showed a significantly lower detection rate (58% and 42%, respectively). These results suggest that a combination of immunohistochemistry and AS-PCR or NGS should be considered for the identification of IDH2 mutations in AITL in a routine setting.

The Role of Activator Protein-1 (AP-1) Family Members in CD30-Positive Lymphomas

The Activator Protein-1 (AP-1) transcription factor (TF) family, composed of a variety of members including c-JUN, c-FOS and ATF, is involved in mediating many biological processes such as proliferation, differentiation and cell death. Since their discovery, the role of AP-1 TFs in cancer development has been extensively analysed. Multiple in vitro and in vivo studies have highlighted the complexity of these TFs, mainly due to their cell-type specific homo- or hetero-dimerization resulting in diverse transcriptional response profiles. However, as a result of the increasing knowledge of the role of AP-1 TFs in disease, these TFs are being recognized as promising therapeutic targets for various malignancies. In this review, we focus on the impact of deregulated expression of AP-1 TFs in CD30-positive lymphomas including Classical Hodgkin Lymphoma and Anaplastic Large Cell Lymphoma.

Non-Hodgkin lymphoma

Lymphomas can affect any organ in the body, present with a wide range of symptoms, and be seen by primary care physicians and physicians from most specialties. They are traditionally divided into Hodgkin's lymphoma (which accounts for about 10% of all lymphomas) and non-Hodgkin lymphoma, which is the topic of this Seminar. Non-Hodgkin lymphoma represents a wide spectrum of illnesses that vary from the most indolent to the most aggressive malignancies. They arise from lymphocytes that are at various stages of development, and the characteristics of the specific lymphoma subtype reflect those of the cell from which they originated. Since this topic was last reviewed in The Lancet in 2012, advances in understanding the biology and genetics of non-Hodgkin lymphoma and the availability of new diagnostic methods and therapies have improved our ability to manage patients with this disorder.

Activating mutations and translocations in the guanine exchange factor VAV1 in peripheral T-cell lymphomas

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of non-Hodgkin lymphomas frequently associated with poor prognosis and for which genetic mechanisms of transformation remain incompletely understood. Using RNA sequencing and targeted sequencing, here we identify a recurrent in-frame deletion (VAV1 Δ778-786) generated by a focal deletion-driven alternative splicing mechanism as well as novel VAV1 gene fusions (VAV1-THAP4, VAV1-MYO1F, and VAV1-S100A7) in PTCL. Mechanistically these genetic lesions result in increased activation of VAV1 catalytic-dependent (MAPK, JNK) and non-catalytic-dependent (nuclear factor of activated T cells, NFAT) VAV1 effector pathways. These results support a driver oncogenic role for VAV1 signaling in the pathogenesis of PTCL.

Expression patterns of the activator protein-1 (AP-1) family members in lymphoid neoplasms

The activator protein-1 (AP-1) is a dimeric transcription factor composed of proteins belonging to the Jun (c-Jun, JunB and JunD), Fos (c-Fos, FosB, Fra1 and Fra2) and activating transcription factor protein families. AP-1 is involved in various cellular events including differentiation, proliferation, survival and apoptosis. Deregulated expression of AP-1 transcription factors is implicated in the pathogenesis of various lymphomas such as classical Hodgkin lymphomas, anaplastic large cell lymphomas, diffuse large B cell lymphomas and adult T cell leukemia/lymphoma. The main purpose of this review is the analysis of the expression patterns of AP-1 transcription factors in order to gain insight into the histophysiology of lymphoid tissues and the pathology of lymphoid malignancies.

Primary gastric natural killer/T-cell lymphoma with diffuse CD30 expression and without CD56 expression: A case report

The majority of natural killer (NK)/T-cell lymphomas occur in the nasal cavity and rarely involve the stomach. They possess a specific immunophenotype, with the expression of cluster of differentiation (CD)56, CD2 and CD3ε, but without CD3 expression. Few cases of NK/T-cell lymphoma have partial CD30 expression. The present study reveals a unique case of a 41-year-old female patient with gastric NK/T-cell lymphoma that did not express CD56 and diffusely expressed CD30. Immunohistochemical staining demonstrated that the tumor cells expressed CD3ε, CD43, CD30 and granzyme B and did not express CD2, CD4, CD5, CD7, CD8, CD56, anaplastic lymphoma kinase, CD20, paired box-5 or pan cytokeratin. Based on the immunostaining profile and morphological features, the initial diagnosis considered was gastric anaplastic large cell lymphoma. However, following a consultation with other pathologists, the Epstein-Barr virus (EBV) status of the patient was investigated to exclude a diagnosis of NK/T-cell lymphoma. Notably, the signal for EBV RNA was diffuse positive. Therefore, the final diagnosis was corrected to NK/T-cell lymphoma. To the best of our knowledge, the present study is the first to report NK/T-cell lymphoma in the stomach with a diffuse CD30-positive and CD56-negative phenotype.

[Molecular pathogenesis of peripheral T-cell lymphoma (1): angioimmunoblastic T-cell lymphoma, peripheral T-cell lymphoma, not otherwise specified and anaplastic large cell lymphoma]

Peripheral T-cell lymphomas (PTCL) belong to the group of non-Hodgkin lymphoma and particularly that of mature T/NK cells lymphoproliferative neoplasms. The 2008 WHO classification describes different PTCL entities with varying prevalence. With the exception of the histological subtype "ALK positive anaplastic large cell lymphoma", PTCL are characterized by a poor prognosis. The mechanisms underlying the pathogenesis of these lymphomas are not yet fully understood, but development of genomic high-throughput analysis techniques now allows to extensively identify the molecular abnormalities present in tumor cells. This review aims to summarize the current knowledge and recent advances about the molecular events occurring at the origin or during the natural history of main entities of PTCL. It will be published in two parts : the first is focused on the three more frequent entities, angioimmunoblastic T-cell lymphoma, peripheral T-cell lymphoma, not otherwise specified, and anaplastic large cell lymphoma. The second (which will appear in the november issue) will describe other subtypes less frequent and of poor prognosis : extranodal NK/T-cell lymphoma, nasal type, adult T-cell leukemia/lymphoma, and enteropathy-associated T-cell lymphoma. T or NK cell lymphoproliferative disorders with leukemic presentation, primary cutaneous T-cell lymphoma and very rare subtypes of PTCL whose prevalence is less than 5% (hepatosplenic T-cell lymphoma and subcutaneous panniculitis-like T cell lymphoma) will not be discussed herein.

Changing the paradigms of treatment in peripheral T-cell lymphoma: from biology to clinical practice

Despite enormous advances in our understanding of aggressive lymphomas, it is clear that progress in the peripheral T-cell lymphomas (PTCL) has lagged well behind other B-cell malignancies. Although there are many reasons for this, the one commonly cited notes that the paradigms for diffuse large B-cell lymphoma (DLBCL) were merely applied to all patients with PTCL, the classic "one-size-fits-all" approach. Despite these challenges, progress is being made. Recently, the FDA has approved four drugs for patients with relapsed/refractory PTCL over the past 5 years, and if one counts the recent Japanese approval of the anti-CCR4 monoclonal antibody for patients with adult T-cell leukemia/lymphoma, five drugs have been approved worldwide. These efforts have led to the initiation of no fewer than four randomized clinical studies exploring the integration of these new agents into standard CHOP (cyclophosphamide-Adriamycin-vincristine-prednisone)-based chemotherapy regimens for patients with newly diagnosed PTCL. In addition, a new wave of studies are exploring the merits of novel drug combinations in the disease, an effort to build on the obvious single-agent successes. What has emerged most recently is the recognition that the PTCL may be a disease-characterized by epigenetic dysregulation, which may help explain its sensitivity to histone deacetylase (HDAC) inhibitors, and open the door for even more creative combination approaches. Nonetheless, advances made over a relatively short period of time are changing how we now view these diseases and, hopefully, have poised us to finally improve its prognosis. See all articles in this CCR Focus section, "Paradigm Shifts in Lymphoma."

Uncommon non-Hodgkin lymphomas of childhood: pathological diagnosis, clinical features and treatment approaches

We provide a review of the pathological and clinical features for uncommon B-cell and T-cell lymphomas of childhood with a specific focus on advances in treatment approaches and outcomes. There is clearly a need for prospective investigation of both the clinical and biological features of the uncommon non-Hodgkin lymphoma subtypes in childhood. These results should lead to more uniform and more effective treatment approaches.

Epstein-Barr virus (EBV)-associated lymphoid lesions of the head and neck

Epstein Barr virus (EBV)-related lymphoproliferative processes occur in the head and neck ranging from reactive processes such as infectious mononucleosis to high grade malignant lymphomas. EBV is a ubiquitous herpes virus that infects more than 90% of adults worldwide, and is generally transferred though saliva. Primary infection can occur throughout life. EBV is the first virus linked to malignancies, both epithelial and lymphoid. Both T and B cell lymphomas can be associated with EBV and evidence shows that an individual's response to the acute EBV infection may be critical in the development of subsequent lymphoma. Currently, in situ hybridization for EBER is the most sensitive available test to detect EBV and should be routinely performed in lymphoproliferative lesions of the head and neck. Immunohistochemistry for EBV related proteins, such as LMP1, is much less sensitive than EBER in situ hybridization, but can help determine latency patterns of EBV infection. Although relatively rare, primary EBV-related lymphomas must be considered in the differential of atypical lymphoid proliferations in the head and neck. We present selected EBV-related disorders of the head and neck discussing etiology as well as differential diagnosis.

High intratumoral macrophage content is an adverse prognostic feature in anaplastic large cell lymphoma

AIMS

Macrophage infiltration has been associated with prognosis in several cancers, including lymphoma, but has not been assessed systematically in anaplastic large cell lymphoma (ALCL). The aim of the study was to correlate expression of the macrophage-associated antigens CD68 and CD163 with pre-therapeutic parameters and outcome in a cohort of treatment-naive ALCL patients.

METHODS AND RESULTS

Pre-therapeutic tumour specimens from 52 patients with ALCL were included in a tissue microarray. The intratumoral macrophage content was assessed by immunohistochemical staining for CD68 and CD163, and quantified using digital image analysis. Anaplastic lymphoma kinase (ALK)-positive patients were significantly younger and had a favourable outcome compared with ALK-negative ALCL patients (median age: 42 versus 59 years; P = 0.008). However, ALK expression was not a significant predictor when adjusting for age. Although classical risk factors were distributed evenly between the compared groups, high intratumoral content of CD68 and/or CD163 correlated with poor outcome, in both univariate and multivariate analyses. High intratumoral CD163 content showed the strongest adverse association with both overall and progression-free survival in ALK-negative patients (P < 0.001).

CONCLUSIONS

A high content of intratumoral CD68- and/or CD163-positive macrophages correlates with an adverse outcome in ALK-negative ALCL.

A case of ileal mucosa-associated lymphoid tissue lymphoma accompanied by luminal stricture and arterial spurting

Primary small intestinal lymphoma is relatively uncommon. Small bowel tumors are difficult to diagnose, because they are usually asymptomatic in the initial phase, and they are not easily detected by traditional methods of investigating the small intestine. This case shows a successfully detected and treated gastrointestinal bleeding from rare ileal mucosa-associated lymphoid tissue lymphoma, using double balloon endoscopy.

Prognostic significance of peripheral monocyte count in patients with extranodal natural killer/T-cell lymphoma

Background

Extranodal natural killer/T-cell lymphoma (ENKL) has heterogeneous clinical manifestations and prognosis. This study aims to evaluate the prognostic impact of absolute monocyte count (AMC) in ENKL, and provide some immunologically relevant information for better risk stratification in patients with ENKL.

Methods

Retrospective data from 163 patients newly diagnosed with ENKL were analyzed. The absolute monocyte count (AMC) at diagnosis was analyzed as continuous and dichotomized variables. Independent prognostic factors of survival were determined by Cox regression analysis.

Results

The AMC at diagnosis were related to overall survival (OS) and progression-free survival (PFS) in patients with ENKL. Multivariate analysis identified AMC as independent prognostic factors of survival, independent of International Prognostic Index (IPI) and Korean prognostic index (KPI). The prognostic index incorporating AMC and absolute lymphocyte count (ALC), another surrogate factor of immune status, could be used to stratify all 163 patients with ENKL into different prognostic groups. For patients who received chemotherapy followed by radiotherapy (102 cases), the three AMC/ALC index categories identified patients with significantly different survivals. When superimposed on IPI or KPI categories, the AMC/ALC index was better able to identify high-risk patients in the low-risk IPI or KPI category.

Conclusion

The baseline peripheral monocyte count is shown to be an effective prognostic indicator of survival in ENKL patients. The prognostic index related to tumor microenvironment might be helpful to identify high-risk patients with ENKL.

Gastrointestinal lymphomas: Morphology, immunophenotype and molecular features

Primary gastrointestinal lymphoma comprises 10-15% of all non-Hodgkin lymphomas and encompasses 30-40% of the total extranodal lymphomas. Approximately 60-75% of cases occur in the stomach, and then the small bowel, ileum, cecum, colon and rectum. Lymphoid neoplasms may consist of mature B, T and less commonly extranodal NK/T cells. Of these, the two most frequently encountered histologic subtypes are extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma), where Helicobacter pylori infection is implicated in a number of cases, and diffuse large B cell lymphoma. Several B cell lymphomas are associated with chromosomal aberrations. Enteropathy-associated T cell lymphoma, type I in particular, usually arises in a background of celiac disease. T cell gene rearrangement confirms clonality. NK/T cell neoplasms are invariably associated with Epstein-Barr virus infection and are often aggressive; thus, differentiation from a benign NK-cell enteropathy is paramount. Although incidence of other hematopoietic malignancies in the gastrointestinal tract such as plasma cell myeloma associated with amyloidosis, plasmablastic lymphoma, Hodgkin disease, histiocytic sarcoma and mast cell sarcoma is extremely rare, these entities have been documented, with the latter two demonstrating aggressive clinical behavior. Endoscopic ultrasonography is an important adjunct in disease staging and follow-up. Conservative antibiotic treatment of stage I MALT lymphomas with associated Helicobacter pylori infection achieves good clinical outcome with high remission rate. Chemotherapy, radiation and rarely surgery are reserved for advanced diseases or cases resistant to conservative therapy and those not associated with Helicobacter pylori infection.

Gastrointestinal lymphomas: Morphology, immunophenotype and molecular features

Primary gastrointestinal lymphoma comprises 10-15% of all non-Hodgkin lymphomas and encompasses 30-40% of the total extranodal lymphomas. Approximately 60-75% of cases occur in the stomach, and then the small bowel, ileum, cecum, colon and rectum. Lymphoid neoplasms may consist of mature B, T and less commonly extranodal NK/T cells. Of these, the two most frequently encountered histologic subtypes are extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma), where Helicobacter pylori infection is implicated in a number of cases, and diffuse large B cell lymphoma. Several B cell lymphomas are associated with chromosomal aberrations. Enteropathy-associated T cell lymphoma, type I in particular, usually arises in a background of celiac disease. T cell gene rearrangement confirms clonality. NK/T cell neoplasms are invariably associated with Epstein-Barr virus infection and are often aggressive; thus, differentiation from a benign NK-cell enteropathy is paramount. Although incidence of other hematopoietic malignancies in the gastrointestinal tract such as plasma cell myeloma associated with amyloidosis, plasmablastic lymphoma, Hodgkin disease, histiocytic sarcoma and mast cell sarcoma is extremely rare, these entities have been documented, with the latter two demonstrating aggressive clinical behavior. Endoscopic ultrasonography is an important adjunct in disease staging and follow-up. Conservative antibiotic treatment of stage I MALT lymphomas with associated Helicobacter pylori infection achieves good clinical outcome with high remission rate. Chemotherapy, radiation and rarely surgery are reserved for advanced diseases or cases resistant to conservative therapy and those not associated with Helicobacter pylori infection.

The spectrum of lymphoblastic, nodal and extranodal T-cell lymphomas: characteristic features and diagnostic dilemmas

T-cell lymphomas represent a heterogeneous group of neoplasms that encompass considerable clinical, morphologic, and immunophenotypic variation. The diagnosis of T-cell lymphoma is challenging because of its relative rarity, the lack of an immunophenotypic marker of clonality, and significant morphologic overlap with infectious/inflammatory processes and neoplasms, including Hodgkin and other non-Hodgkin lymphomas, and even mesenchymal or epithelial lesions. In the current World Health Organization classification of hematopoietic tumors, all except 1 subtype (ie, T-lymphoblastic lymphoma) are recognized as mature neoplasms derived from postthymic T cells. In addition to T-lymphoblastic lymphoma, this review will focus on nodal and extranodal T-cell lymphomas and exclude T-cell lymphomas presenting primarily in the skin. Extranodal natural-killer-cell/T-cell lymphoma, nasal type, will also be discussed because the derivation of this lymphoma from natural killer and natural killer-like T cells shows morphologic and immunophenotypic features that overlap with other T-cell lymphomas. In this review, we discuss the salient clinicopathologic, immunophenotypic, and genetic features, as well as our approaches to the diagnosis of lymphoblastic, nodal, and extranodal T-cell lymphomas.

Update: peripheral T-cell lymphomas

Peripheral T-cell lymphomas (PTCLs) are a group of biologically heterogeneous but typically aggressive diseases. Progress in understanding and developing optimal therapies for PTCLs has been hampered by disease rarity and only relatively recent recognition of the importance of the T-cell phenotype. The International Peripheral T-cell Lymphoma Project was a large collaborative effort to provide a broader understanding of prognosis. Recently, several new therapies have shown promise in the treatment of PTCLs.