METTL3 regulates M6A methylation-modified EBV-pri-miR-BART3-3p to promote NK/T cell lymphoma growth.

OBJECTIVE: N6-methyladenosine (M6A) is the most prevalent epigenetic alteration. Methyltransferase-like 3 (METTL3) is a key player in the control of M6A modification. Methyltransferase promote the processing of mature miRNA in an M6A-dependent manner, thereby participating in disease occurrence and development. However, the regulatory mechanism of M6A in NK/T cell lymphoma (NKTCL) remains unclear. PATIENTS AND METHODS: We determined the expression of METTL3 and its correlation with clinicopathological features using qRT-PCR and immunohistochemistry. We evaluated the effects of METTL3 on NKTCL cells using dot blot assay, CCK8 assay and subcutaneous xenograft experiment. We then applied M6A sequencing combined with gene expression omnibus data to screen candidate targets of METTL3. Finally, we investigated the regulatory mechanism of METTL3 in NKTCL by methylated RNA immunoprecipitation and RNA immunoprecipitation (RIP) assays. RESULTS: We demonstrated that METTL3 was highly expressed in NKTCL cells and tissues and indicated poor prognosis. The METTL3 expression was associated with NKTCL survival. Functionally, METTL3 promoted the proliferation capability of NKTCL cells in vitro and in vivo. Furthermore, EBV-miR-BART3-3p was identified as the downstream effector of METTL3, and silencing EBV-miR-BART3-3p inhibited the proliferation of NKTCL. Finally, we confirmed that PLCG2 as a target gene of EBVmiR-BART3-3p by relative assays. CONCLUSIONS: We identified that METTL3 is significantly up-regulated in NKTCL and promotes NKTCL development. M6A modification contributes to the progression of NKTCL via the METTL3/EBV-miR-BART3-3p/PLCG2 axis. Our study is the first to report that M6A methylation has a critical role in NKTCL oncogenesis, and could be a potential target for NKTCL treatment.

Comprehensive Genetic Profiling Reveals Frequent Alterations of Driver Genes on the X Chromosome in Extranodal NK/T-cell Lymphoma.

Extranodal NK/T-cell lymphoma (ENKTCL) is an Epstein-Barr virus (EBV)-related neoplasm with male dominance and a poor prognosis. A better understanding of the genetic alterations and their functional roles in ENKTCL could help improve patient stratification and treatments. In this study, we performed a comprehensive genetic analysis of 178 ENKTCL cases to delineate the landscape of mutations, copy number alterations (CNA), and structural variations, identifying 34 driver genes including six previously unappreciated ones, namely, HLA-B, HLA-C, ROBO1, CD58, POT1, and MAP2K1. Among them, CD274 (24%) was the most frequently altered, followed by TP53 (20%), CDKN2A (19%), ARID1A (15%), HLA-A (15%), BCOR (14%), and MSN (14%). Chromosome X losses were the most common arm-level CNAs in females (∼40%), and alterations of four X-linked driver genes (MSN, BCOR, DDX3X, and KDM6A) were more frequent in males and females harboring chromosome X losses. Among X-linked drivers, MSN was the most recurrently altered, and its expression was lost in approximately one-third of cases using immunohistochemical analysis. Functional studies of human cell lines showed that MSN disruption promoted cell proliferation and NF-κB activation. Moreover, MSN inactivation increased sensitivity to NF-κB inhibition in vitro and in vivo. In addition, recurrent deletions were observed at the origin of replication in the EBV genome (6%). Finally, by integrating the 34 drivers and 19 significant arm-level CNAs, nonnegative matrix factorization and consensus clustering identified two molecular groups with different genetic features and prognoses irrespective of clinical prognostic factors. Together, these findings could help improve diagnostic and therapeutic strategies in ENKTCL. Significance: Integrative genetic analyses and functional studies in extranodal NK/T-cell lymphoma identify frequent disruptions of X-linked drivers, reveal prognostic molecular subgroups, and uncover recurrent MSN alterations that confer sensitivity to NF-κB inhibition.

Co-occurrence of Epstein-Barr virus-positive nodal T/NK-cell lymphoma and nodal T-follicular helper cell lymphoma of different clonal origins: An autopsy case report.

Nodal T-follicular helper cell lymphoma (TFHL) is a subset of T-cell lymphoma and frequently co-occurs with Epstein-Barr virus (EBV)-positive B-cell lymphoma but not with T/NK-cell lymphoma. Recently, a new entity with a worse prognosis, called EBV-positive nodal T/NK-cell lymphoma (NTNKL) has been established. Here, we report an autopsy case of synchronous multiple lymphomas, including TFHL and NTNKL. The patient was a 78-year-old female admitted with pneumonia. Although pneumonic symptoms were improved, fever, pancytopenia, and disseminated intravascular coagulation emerged, implicating lymphoma. She died on the 21st hospital day without a definitive diagnosis. The autopsy revealed the enlargement of multiple lymph nodes throughout her body. Histological analysis revealed three distinct regions in the left inguinal lymph node. The first region consists of small-sized lymphocytes with T-follicular helper phenotype and extended follicular dendritic cell meshwork, indicating TFHL. The second region included EBV-positive large B cells. The third region comprised EBV-positive large cells with cytotoxic T/NK cell phenotype, indicating NTNKL. Clonality analysis of the first and the third regions showed different patterns. Since various hematopoietic malignancies progress from common clonal hematopoiesis according to existing literature, this case may help to understand TFHL and NTNKL.

EBV+ nodal T/NK-cell lymphoma associated with clonal hematopoiesis and structural variations of the viral genome.

ABSTRACT: Epstein-Barr virus (EBV)-positive (EBV+) nodal T- and natural killer (NK)-cell lymphoma is a peripheral T-cell lymphoma (EBV+ nPTCL) that presents as a primary nodal disease with T-cell phenotype and EBV-harboring tumor cells. To date, the genetic aspect of EBV+ nPTCL has not been fully investigated. In this study, whole-exome and/or whole-genome sequencing was performed on 22 cases of EBV+ nPTCL. TET2 (68%) and DNMT3A (32%) were observed to be the most frequently mutated genes whose presence was associated with poor overall survival (P = .004). The RHOA p.Gly17Val mutation was identified in 2 patients who had TET2 and/or DNMT3A mutations. In 4 patients with TET2/DNMT3A alterations, blood cell-rich tissues (the bone marrow [BM] or spleen) were available as paired normal samples. Of 4 cases, 3 had at least 1 identical TET2/DNMT3A mutation in the BM or spleen. Additionally, the whole part of the EBV genome was sequenced and structural variations (SVs) were found frequent among the EBV genomes (63%). The most frequently identified type of SV was deletion. In 1 patient, 4 pieces of human chromosome 9, including programmed death-ligand 1 gene (PD-L1) were identified to be tandemly incorporated into the EBV genome. The 3' untranslated region of PD-L1 was truncated, causing a high-level of PD-L1 protein expression. Overall, the frequent TET2 and DNMT3A mutations in EBV+ nPTCL seem to be closely associated with clonal hematopoiesis and, together with the EBV genome deletions, may contribute to the pathogenesis of this intractable lymphoma.

Characterization of T-/natural killer cell lymphoproliferative neoplasms associated with systemic, chronic, active Epstein-Barr virus in adults: A report of 5 cases in a Western population.

OBJECTIVES: Because of its low frequency in adult populations and clinical and laboratory overlap with hemophagocytic lymphohistiocytosis and other T-cell lymphomas, T-cell/natural killer (NK) cell systemic, chronic, active Epstein-Barr virus (EBV) (T/NK sCAEBV) infection remains underdiagnosed, preventing critical, prompt therapeutic interventions. METHODS: We report a 5-case series that included 2 adult patients with T/NK sCAEBV and 3 additional adult patients with T/NK lymphomas with concomitant systemic EBV infection to review these entities' overlapping diagnostic and clinical features. RESULTS: Approximately 95% of the world population has been infected with EBV during their lifetime, and infection is usually asymptomatic, with symptomatic cases eventually resolving spontaneously. A small subset of immunocompetent patients develops CAEBV, a life-threatening complication resulting from EBV-infected T-cell or NK cell neoplastic lymphocytes. The sites of end-organ damage in T/NK sCAEBV demonstrate pathologic findings such as reactive lymphoid proliferations, making the diagnosis difficult to establish, with the only curative option being an allogeneic hematopoietic stem cell transplant. CONCLUSIONS: This diagnosis is most prevalent in Asia, with few cases reported in Western countries. Adult age is an independent risk factor for poor outcomes, and most cases are diagnosed in pediatric populations.

Estimating the global burden of Epstein-Barr virus-related cancers.

BACKGROUND: More than 90% of the adult population globally is chronically infected by the Epstein-Barr virus (EBV). It is well established that EBV is associated with a number of malignancies, and advances in knowledge of EBV-related malignancies are being made every year. Several studies have analysed the global epidemiology and geographic distribution of EBV-related cancers. However, most have only described a single cancer type or subtype in isolation or limited their study to the three or four most common EBV-related cancers. This review will present an overview on the spectrum of cancers linked to EBV based on observations of associations and proportions in the published literature while also using these observations to estimate the incidence and mortality burden of some of these cancers. METHOD: We have reviewed the literature on defining features, distribution and outcomes across six cancers with a relatively large EBV-related case burden: Nasopharyngeal carcinoma (NPC), Gastric carcinoma (GC), Hodgkin lymphoma (HL), Burkitt lymphoma (BL), Diffuse large B-cell lymphoma (DLBCL) and Extranodal NK/T-cell lymphoma, Nasal type (ENKTL-NT). We retrieved published region-specific EBV-related case proportions for NPC, GC, HL and BL and performed meta-analyses on pooled region-specific studies of EBV-related case proportions for DLBCL and ENKTL-NT. We match these pooled proportions with their respective regional incidence and mortality numbers retrieved from a publicly available cancer database. Additionally, we also reviewed the literature on several other less common EBV-related cancers to summarize their key characteristics herein. CONCLUSION: We estimated that EBV-related cases from these six cancers accounted for 239,700-357,900 new cases and 137,900-208,700 deaths in 2020. This review highlights the significant global impact of EBV-related cancers and extends the spectrum of disease that could benefit from an EBV-specific therapeutic.

Combination of Gemcitabine and Thymosin alpha 1 exhibit a better anti-tumor effect on nasal natural killer/T-cell lymphoma.

BACKGROUND: Nasal natural killer/T-cell lymphoma (NNKTL) is an aggressive and poor prognostic malignant tumor along with high-level infection of Epstein-Barr virus (EBV). Gemcitabine (Gem) and Thymosin alpha 1 (Tα1) exert an anti-tumor effect in various cancers. However, the effect of the combination of Gem and Tα1 in NNKTL remains unknown. METHODS: SNK6 cells were treated with Gem, Tα1 and Gem plus Tα1 for 48 h. The expression levels of EBV and inflammatory factors were measured by qRT-PCR assay. The effect of Gem and Tα1 on cell viability, proliferation, apoptosis, autophagy was detected by CCK-8, colony formation, flow cytometry, autophagic flux measurement, respectively. Western blot was used to evaluate the expression of proteins related to epithelial-mesenchymal transition (EMT), apoptosis and autophagy. In vivo xenograft models were used to further verify the roles of Gem and Tα1. Tumors were removed for weight measurement, H&E and IHC staining. RESULTS: We identified that the half maximal inhibitory concentration (IC50) of Gem and Tα1 was 116.5 µmol/ml and 1.334 µmol/ml. Alone or combined administration of Gem and Tα1 dramatically attenuated the EBV viral load and promoted inflammatory factors expression in SNK6 cells, among which the combination of Gem and Tα1 treatment showed the most significant effect. Besides, combination treatment with Gem and Tα1 markedly inhibited cell growth and EMT progress, and enhanced apoptosis and autophagy. Similarly, Gem combined with Tα1 suppressed tumor growth, promoted apoptosis and autophagy in vivo. Additionally, combination treatment with Gem and Tα1 inhibited PI3K/AKT/mTOR pathway. CONCLUSION: In summary, combination administration of Gem and Tα1 suppressed the progression of NNKTL in vivo and in vitro. Our study provided an effective therapeutic strategy potentially for the clinical treatment of NNKTL.

Secondary parenchymal CNS involvement by lymphoma including rare types: Follicular and EBV-positive NK/T cell lymphoma, nasal type.

BACKGROUND: Secondary CNS involvement by systemic lymphomas (SCNSL) is uncommon, but when it occurs, is usually due to diffuse large B cell lymphoma (DLBCL). Three recent unusual cases serve to highlight diagnostic challenges. OBJECTIVE: To report SCNSL from DLBCL and two unusual lymphoma types: follicular lymphoma with high-grade transformation to DLBCL and NK/T cell lymphoma, nasal type (ENKL), nasal type. RESULTS: SCNSL in the DLBCL case occurred at 7-year interval from primary in a 54-year-old woman who presented with stroke-like symptoms and a right postcentral gyrus 2.6 × 2.9 × 2.6 cm. mass. The follicular lymphoma occurred at 6-month interval in a 69-year-old woman with 1 month of diplopia and 2 weeks of cognitive decline; multifocal lesions involved temporal lobe, subependymal periventricular areas, brainstem, cerebellum, hypothalamus, corpus callosum and gyrus rectus. The ENKL occurred at 25-month interval from nasal biopsy in a 45-year-old man with 1 week of altered mental status; multifocal cerebral and brainstem lesions were identified. Histological features in cases 1 and 3 were identical to the primary lymphoma, with high-grade transformation to DLBCL in the follicular lymphoma. CONCLUSION: Unusual features in our series include longer interval from primary to relapse in case 1 with DLBCL (usually <2 years of diagnosis), and SCNSL occurring from either follicular lymphoma or EKNL, nasal type (<6% of cases). Pathologists play an important role in excluding infectious, especially in cases with parenchymal lesions and characterizing the lymphoma type in SCNSL.

Updating targets for natural killer/T-cell lymphoma immunotherapy.

Natural killer/T-cell lymphoma (NKTCL) is a highly invasive subtype of non-Hodgkin lymphoma, typically positive for cytoplasmic CD3, CD56, cytotoxic markers, including granzyme B and TIA1, and Epstein-Barr virus (EBV). The current treatment methods for NKTCL are associated with several drawbacks. For example, chemotherapy can lead to drug resistance, while treatment with radiotherapy alone is inadequate and results in frequent relapses. Moreover, hematopoietic stem cell transplantation exhibits limited efficacy and is not well recognized by domestic and foreign experts. In recent years, immunotherapy has shown good clinical results and has become a hot spot in cancer research. Clinical activity of targeted antibodies, such as daratumumab (anti-CD38 antibody) and brentuximab vedotin (anti-CD30 antibody), have been reported in NKTCL. Additionally, dacetuzumab and Campath-1H have demonstrated promising results. Further encouraging data have been obtained using checkpoint inhibitors. The success of these immunotherapy agents is attributed to high expression levels of programmed death-ligand 1 in NKTCL. Furthermore, anti-CCR4 monoclonal antibodies (mAbs) exert cytotoxic actions on both CCR4+ tumor cells and regulatory T cells. Depletion of these cells and the long half-life of anti-CCR4 mAbs result in enhanced induction of antitumor effector T cells. The role of IL10 in NKTCL has also been investigated. It has been proposed that exploitation of this cytokine might provide potential novel therapeutic strategies. Cellular immunotherapy with engineered cytotoxic T lymphocytes targeted against LMP1 and LMP2 has shown promising results and sustained remission. Cellular immunotherapy may be used either as maintenance therapy following initial induction chemotherapy or in cases of relapsed/refractory disease. The present review outlines the known immunotherapy targets for the treatment of NKTCL.

Analysis of latent T-cell epitopes in Epstein-Barr virus isolated from extranodal nasal-type natural killer/T-cell lymphoma in Taiwanese population.

Extranodal nasal-type natural killer (NK)/T-cell lymphoma (NKTCL) is an aggressive lymphoma that is prevalent among East Asian and South American populations. Although Epstein-Barr virus (EBV) is commonly detected in NKTCL, there are limited studies that have analyzed the EBV genomic variations in NKTCL. In this study, 8 EBV latent genes were analyzed using targeted gene sequencing in 23 formalin-fixed paraffin-embedded tissues derived from 18 patients with NKTCL. Five cases with paired samples were comparatively analyzed. The consistency of EBV sequencing data between tissue samples was high (96.3%-98.7%), whereas that of variant calling among the tissue samples and plasma samples (74.3%-79.2%) was low. The highest densities of non-synonymous variants were detected in the EBNA3B gene. Among the 74 known T-cell epitopes, 363 non-synonymous variants were identified in 32 (43.2%) epitopes. Additionally, the AVFDRKSDAK (A1S/P and V2F/M/L) and YHLIVDTDSL (I4L and L10R/V/G/H) epitopes were associated with 5 patterns of amino acid changes in EBNA3B and EBNA-2, respectively. The frequency of variation in the human leukocyte antigen (HLA)-restricted epitopes with corresponding HLA types common among Taiwanese population was significantly low (P = 0.011), whereas that in anchor residues was significantly high (P = 0.012). In conclusion, this study demonstrated the genomic diversity of EBV in NKTCL and its correlation with the HLA-restricted epitope variations in Taiwanese population. The findings of this study provide useful insights for the development of novel therapeutic strategies for NKTCL.

Nodal EBV+ cytotoxic T-cell lymphoma: A literature review based on the 2017 WHO classification.

Nodal Epstein-Barr virus (EBV)-positive cytotoxic T-cell lymphoma (CTL) is a primary nodal peripheral T-cell lymphoma (PTCL) characterized by a cytotoxic phenotype and EBV on the tumor cells. This disease reportedly accounts for 21% of PTCL not otherwise specified (NOS). However, few nodal EBV+ lymphomas have been documented in detail. Nodal EBV+ CTL and nasal-type NK/T-cell lymphoma (NKTL) both exhibit cytotoxic molecule expression and EBV positivity on the tumor cells; however, nodal EBV+ CTL is characterized as a systemic disease without nasopharyngeal involvement, and exhibits a CD8+/CD56- phenotype distinct from NKTL. The clinicopathological uniqueness of nodal EBV+ CTL is further supported by its T-cell origin in most reported cases. In the 2008 WHO classification, it was unclear whether nodal EBV+ CTL should be classified as PTCL or NKTL. However, based on additional data, the 2017 revision classifies nodal EBV+ CTL as PTCL. In the present review, we focus on the clinicopathological characteristics of nodal EBV+ CTL, discuss the relationship between chronic active EBV infection and nodal EBV+ lymphoma, and highlight future perspectives regarding the treatment of this disease.

Extranodal NK/T-Cell Lymphomas: The Role of Natural Killer Cells and EBV in Lymphomagenesis.

Keywords: NK cells, extranodal NK/T-cell lymphoma, EBV.

Mutational profile and EBV strains of extranodal NK/T-cell lymphoma, nasal type in Latin America.

Extranodal NK/T-cell lymphoma (ENKTL) is an Epstein-Barr virus (EBV) associated lymphoma, prevalent in Asia and Latin America. Studies in Asian cohorts have identified some recurrent gene mutations in ENKTL; however, the mutational landscape of ENKTL in Latin America is unknown. In this study, we investigated the mutational profile and EBV strains of 71 ENKTL cases from Latin America (42 from Mexico, 17 from Peru, and 12 from Argentina) and compared it with Asian cohorts. The mutational analysis was performed by next generation sequencing (NGS) using an Ion AmpliSeq™ custom panel covering for the most frequently mutated genes identified in ENKTL. STAT3 was the most frequent mutated gene (16 cases: 23%), followed by MSN (10 cases; 14%), BCOR (9 cases; 13%), DDX3X (6 cases; 8%), TP53 (6 cases; 8%), MGA (3 cases; 4%), JAK3 (2 cases; 3%), and STAT5B (1 case; 1%). Mutations in STAT3, BCOR, and DDX3X were nearly mutually exclusive, suggesting different molecular pathways involved in the pathogenesis of ENKTL; whereas mutations in MGA, MSN, and TP53 were concomitant with other mutations. Most cases (75%) carried Type A EBV without the 30-bp LMP1 gene deletion. The overall survival was significantly associated with serum LDH level, Eastern Cooperative Oncology Group (ECOG) performance status, International Prognostic Index (IPI) score, and therapy (p < 0.05), but not associated with any mutation, EBV strain or deletion in EBV LMP1 gene. In conclusion, mutational analysis of ENKTL from Latin America reveals frequent gene mutations leading to activation of the JAK-STAT pathway (25%), mostly STAT3. Compared to Asian cohorts, BCOR, DDX3X and TP53 mutations were also identified but with different frequencies. None of these mutations were associated with prognosis.

Linfoma Extranodal de Células T/NK en Cavidad Oral. Reporte de un Caso en Chile / Extranodal Lymphoma of T / NK Cells in Oral Cavity. Case Report in Chile

RESUMEN: El linfoma extranodal de células T/NK es una neoplasia maligna agresiva que se caracteriza por una destrucción de estructuras de la línea media de la cara como paladar y fosa nasal. Presentamos el caso de un paciente de sexo masculino, 48 años de edad, consumidor de cocaína, que consulta en la Facultad de Odontología de la Universidad de Chile en Septiembre del 2015 por síntomas de disfagia, rinorrea y que presenta al examen clínico un tumor ulcerado que compromete paladar duro y blando, de un mes de evolución. Se confirma diagnóstico de linfoma de células T/NK con una batería de pruebas inmunohistoquímicas. Esta patología, aunque infrecuente, siempre debe ser considerada dentro los diagnósticos diferenciales en tumores ulcerados en esta localización.

ABSTRACT: Extranodal T / NK cell lymphoma is an aggressive malignant neoplasm characterized by destruction of midline structures of the face such as the palate and nasal fossa. We present the case of a male patient, 48 years old, cocaine user, who consults at the Faculty of Dentistry of the Universidad de Chile in September of 2015 due to symptoms of dysphagia, rhinorrhea and presenting to the clinical examination an ulcerated tumor which compromises hard and soft palate, a month of evolution. Diagnosis of T / NK cell lymphoma is confirmed with a battery of immunohistochemical tests. This pathology, although infrequent, should always be considered within the differential diagnoses in ulcerated tumors of this location.

Expression and clinical significance of neuropilin-1 in Epstein-Barr virus-associated lymphomas.

BACKGROUND: The expression of neuropilin-1 (NRP-1) in Epstein-Barr virus (EBV)-associated lymphomas and its relationships with clinicopathological parameters was investigated. METHODS: The researchers compared 111 cases of patients with lymphoma to 20 cases of reactive lymphoid hyperplasia. In situ hybridization was applied to observe the expression of EBV-encoded RNA (EBER) in lymphomas, and immunohistochemistry was used to detect the NRP-1 expression in lymphoma tissues and lymph node tissues with reactive hyperplasia. RESULTS: In these 111 cases, the EBER of 62 cases (55.9%) appeared positive. NRP-1 was relatively highly expressed in lymphomas (P= 0.019). Further, NRP-1 showed higher expression in lymphomas with positive EBER than in negative ones. A comprehensive analysis revealed that NRP-1 was differently expressed in NK/T-cell lymphoma, Hodgkin's lymphoma, diffuse large B-cell lymphoma, and anaplastic large cell lymphoma (P= 0.027). Moreover, highly expressed NRP-1 was found to be a useful independent prognostic factor in assessing overall survival and progression-free survival rates in cases of non-Hodgkin's lymphoma (NHL). CONCLUSIONS: NRP-1 exhibited higher expression in lymphomas, and it was positively expressed in EBV-positive lymphomas. Moreover, highly expressed NRP-1 can be used as an undesirable independent prognostic factor in NHL.

Intravascular NK/T-cell lymphoma: clinicopathological and integrated molecular analysis of two cases provides a clue to disease pathogenesis.

AIMS: To elucidate the clinicopathological and molecular features of intravascular NK/T-cell lymphoma (IVNKTCL). METHODS: Two cases of IVNKTCL were retrieved from a single-centre cohort composed of 25 intravascular lymphomas. Whole-exome and RNA sequencing and immunohistochemistry were performed. RESULTS: We identified somatic mutations in the following epigenetic regulators: four histone genes (HIST1H2AN, HIST1H2BE, HIST1H2BN and H3F3A), histone deacetylase (HDAC5), two helicases (WRN and DDX3X), two methylation-related enzymes (TET2 and DNMT1) and the SNI/SWF pathway (ARID1A). Copy number analysis identified driver gene alterations comprising the loss of ARID1B, HACE1 and SMAD4, and the gain of SOX2 and histone clusters. RNA sequencing analysis did not indicate the presence of any fusion gene. Both cases were positive for Epstein-Barr virus (EBV) and showed strong expression of programmed death-ligand 1 (PD-L1). CONCLUSIONS: This study raises the possibility that, at least for some patients, IVNKTCL may be considered an epigenetic disease with EBV infection-associated aetiopathogenesis.

Laryngeal Extranodal Nasal-type Natural Killer/T-cell Lymphoma: A Clinicopathologic Study of 31 Cases in China.

Extranodal natural killer/T-cell lymphoma, nasal-type (ENKTL-N) initially presented in larynx is a rare condition without distinctive clinicopathologic features, with a challenging pathologic diagnosis. This study aimed to evaluate the clinicopathologic features and diagnosis of laryngeal ENKTL-N and spread awareness regarding ENKTL-N. A series of 31 cases of laryngeal ENKTL in one Chinese institution over a 9-year interval was retrospectively analyzed. Median age was 50 years (range, 13 to 77 y) with a male/female ratio of 5.2:1 (26/5). All patients initially presented with hoarseness and/or laryngalgia, and 10 patients (32.3%) experienced B symptoms. The supraglottic region was the most common site of occurrence (58.1%), the glottic area being the rarest site (6.5%). The mucosal squamous epithelium was detected in 26 specimens and pseudoepitheliomatous hyperplasia was observed in 8 cases (8/26, 30.8%). "Keratin-pearls" and a "pseudoinvasive" pattern were observed in 2 cases. Follow-up data were available for 26 patients (83.9%), the median survival duration was 9 months, and the overall survival rate at 5 years was 29.6%. Univariate analysis revealed that patients experiencing B symptoms (P=0.019) and age above 60 years had a significantly low survival (P=0.049) and that combined radiotherapy and chemotherapy prolongs overall survival (P<0.001). Laryngeal ENKTL-N is a rare entity with high aggressiveness and a poor prognosis. Multiple biopsies are usually required owing to secondary infection and massive necrosis. Laryngeal EKTL-N may mimic inflammatory lesions or well-differentiated squamous cell carcinoma. Therefore, clinical vigilance is essential to prevent misdiagnosis or a delayed diagnosis.