Extranodal Natural Killer/T-Cell Lymphoma in Children and Adolescents: A Report of 17 Cases in China

An exploratory study on the differential diagnostic indicators between adult systemic EBV-positive T-cell lymphoproliferative disorders and angioimmunoblastic T-cell lymphoma with multiple EBV infections

BACKGROUND

The differential diagnosis between adult systemic EBV-positive T-cell lymphoproliferative disorders (EBV+ T-LPD) and angioimmunoblastic T-cell lymphoma (AITL) with multiple EBV infections is difficult, and distinguishing between the two has become a diagnostic challenge for pathologists. Given that the clinical treatment plans are different, an accurate diagnosis is a prerequisite to ensure effective treatment, therefore, it is extremely necessary and meaningful to find effective pathological indicators for distinguishing between two diseases.

METHODS

We present a retrospective study comparing 7 cases of adult EBV+ T-LPD and 16 cases of AITL with multiple EBV infections diagnosed at our institution from 2017 to 2022. Differences in immunophenotype, type of EBV-infected cells, clonality and gene mutations between the two groups of cases were compared by immunohistochemical staining, double-label staining, TCR gene rearrangement and next-generation sequencing analysis.

RESULTS

7 cases of adult EBV+ T-LPD: all cases had no more than 1 T follicular helper (THF) marker was expressed, and there were significantly more EBER+/CD3 + cells than EBER+/CD20 + cells; 5 cases had mutation detection results, in which only 1 had the characteristic KMT2D mutation, 2 had TET2 mutations, and no common mutations such as DDX3X were detected.16 cases of AITL with multiple EBV infections: all cases were found to express at least 2 TFH markers, with 87% of them expressing at least 3 TFH markers., and had significantly more EBER+/CD20 + cells than EBER+/CD3 + cells; 4 cases had mutation test results, with mutated high-frequency genes being TET2 (100%, and all of them had 2 or more TET2 mutations) and RHOA G17V (100%), DNMT3A mutation occurred in 2 cases (50%), and IDH2 R172 mutation occurred in 1 case (25%).

CONCLUSIONS

We found that the expression pattern of TFH markers, the types of cells predominantly infected by EBV and the different mutations can all be used as effective pathological indicators for distinguishing between two diseases.

Clinicopathological Features of Epstein-Barr Virus-Positive Neuroendocrine Carcinoma: Analysis of Twenty-Two Cases

Epstein-Barr Virus (EBV)-positive neuroendocrine carcinoma (NEC) is a rare neoplasm with limited histopathological and therapeutic data. This report presents 22 cases of EBV-positive NEC, analyzing age distribution, morphology, and immunophenotype. The median patient age was 47 years (range: 27-67 years), with a male-to-female ratio of 17:5. Most cases (86%, 19/22) were localized to the nasal cavity or nasopharynx, while the remaining three (14%, 3/22) involved the lung, eyelid, and chest wall. Tumors were identified as small cell neuroendocrine carcinoma (SCNEC) or large cell neuroendocrine carcinoma (LCNEC) based on cellular morphology. Immunohistochemical analysis showed positivity for at least one, but generally, two neuroendocrine markers and INI1, while negativity for NUT and squamous cell carcinoma markers, such as p63, p40, and CK5/6. In situ hybridization consistently revealed EBV early RNAs (EBERs) in all cases. Notably, eight patients benefited from chemoradiotherapy. Recognizing this rare tumor is essential for optimizing treatment strategies.

Extranodal NK/T-Cell Lymphoma Predominantly Composed of Anaplastic Cells: A Frequently Misdiagnosed and Highly Aggressive Variant

Extranodal NK/T-cell lymphoma (ENKTL) is a non-Hodgkin lymphoma associated with the Epstein-Barr virus that primarily affects individuals in East Asia and indigenous populations in Central and South America. Morphologically, ENKTL typically consists of medium-sized cells or a combination of small and large cells. This report presents 10 cases characterized by predominantly anaplastic cells with diffuse expression of CD30, resembling anaplastic lymphoma kinase-negative anaplastic large cell lymphoma (ALK-negative ALCL) and demonstrating highly aggressive behavior. The cohort included 9 males and 1 female, ranging in age from 29 to 65 years (median age: 47 y). Eight patients presented with nasal disease, while 2 had non-nasal disease. Five patients had stage I/II disease, and the remaining 5 had stage III/IV disease. Morphologically, necrosis was observed in 9 cases, angiocentric-angiodestructive growth in 3 cases, and pseudoepitheliomatous hyperplasia in 2 cases. Anaplastic cells predominated in all cases, with some displaying eccentric, horseshoe-shaped, or kidney-shaped nuclei (referred to as "Hallmark" cells). The morphology profile was monomorphic in 3 cases and polymorphic in 7 cases. Immunohistochemically, all cases tested positive for cytotoxic granule markers (TIA1 and granzymeB) and Epstein-Barr virus-encoded RNA. Cytoplasmic expression of CD3ε and CD56 was observed in 9 of 10 cases. Interestingly, most cases (7 of 8) exhibited variable expression of MuM1, ranging from 10% to 90%. All cases showed diffuse positivity for CD30 but were negative for ALK, resulting in 3 cases being initially misdiagnosed as ALK-negative ALCL. Compared with nonanaplastic cases, anaplastic cells predominant ENKTL had a significantly higher frequency of "B" symptoms, bone marrow involvement, hemophagocytic lymphohistiocytosis, and higher Ki67 proliferative index. These findings provide valuable information for pathologists, expanding their understanding of the cytologic spectrum of ENKTL. This rare variant of ENKTL, characterized by the predominance of anaplastic cells and diffuse CD30 expression, exhibits high aggressiveness and should be differentiated from ALK-negative ALCL. Awareness of this uncommon variant is crucial in preventing misdiagnosis and ensuring the timely initiation of therapy.

The expression and clinical significance of PLK1/p-PLK1 protein in NK/T cell Lymphoma

AIMS

To investigate the expression of polo-like kinase 1 protein (PLK1) and its phosphorylation level (p-PLK1) in extranodal NK/T cell lymphoma (NKTCL) and their correlation with clinical characteristics and prognosis.

METHODS

We collected 40 cases of NKTCL (referred to as the experimental group), which received diagnoses at the First Affiliated Hospital of Zhengzhou University between January 2018 and October 2022. Concurrently, we assembled a control group, including 20 cases afflicted with nasopharyngeal mucosal lymphoid hyperplasia diseases during the same timeframe. We utilized immunohistochemical techniques to evaluate the levels of PLK1 and p-PLK1 expression in both the experimental and control groups. Subsequently, we conducted an analysis to identify disparities in their expression and explore their relationships with clinical characteristics and patient prognosis.

RESULTS

Among the 40 NKTCL patients, there were 27 males and 11 females, with a median age of 51 years (range 12-80 years). Compared to the control group, the tissue samples of NKTCL patients exhibited significantly elevated expression levels and active phosphorylation levels of PLK1 (P < 0.05). Correlation analysis of the immunohistochemical H score and Ki-67 positive rate of PLK1 and p-PLK1, revealed a significant positive correlation for both (P < 0.0001, each). No statistically significant differences were observed in the distribution of PLK1 and p-PLK1 expression in NKTCL patients with respect to gender, age, Ann Arbor stage, PINK-E score, B-symptoms, lactate dehydrogenase, β2-microglobulin, blood EBV-DNA, bone marrow invasion, and lymph node metastasis (p > 0.05). Grouping based on PLK1 and p-PLK1 immunohistochemical H-scores revealed that the high expression of PLK1 and p-PLK1 was associated with poor prognosis.

CONCLUSIONS

The expression levels and active phosphorylation levels of PLK1 were significantly increased in NK/T cell lymphoma, and patients with overexpression of PLK1 and p-PLK1 had a poorer prognosis.

Challenges in the Diagnosis of Epstein-Barr Virus-positive Inflammatory Follicular Dendritic Cell Sarcoma: Extremely Wide Morphologic Spectrum and Immunophenotype

Epstein-Barr virus (EBV)-positive inflammatory follicular dendritic cell (FDC) sarcoma (EBV + IFDCS) is a rare entity, and its histopathological characteristics have not been fully described. Here, we investigated the wide morphologic spectrum and immunophenotype of this tumor with the aim to help avoid misdiagnosis. Thirteen cases of EBV + IFDCS were retrospectively analyzed, combined with a review of 70 cases reported in the literature. The median age of patients was 49 (range, 29 to 67 y). Six patients were male and 7 were female. Most cases (92.3%, 12/13) occurred in the liver or spleen, and only 1 case affected an extra-hepatosplenic site (lung, 7.7%, 1/13). Tumors were assessed for a variety of histologic features and assigned to the following morphologic groups: classic type (53.8%, 7/13), lymphoma-like subtype (38.5%, 5/13), and hemangioma-like subtype (7.7%, 1/13). The classic type had distinct EBV-positive neoplastic cells with a fascicular or storiform growth pattern, variable lymphoplasmacytic infiltrates, and blood vessels. The lymphoma-like subtype had extremely prominent lymphoplasmacytic infiltrates (resembling marginal zone lymphoma with plasmacytoid differentiation) with singly dispersed distinct EBV-positive neoplastic cells, highlighted by in situ hybridization for EBV-encoded small RNA. The hemangioma-like subtype had extremely prominent blood vessels with hyaline and/or fibrinoid degeneration, singly dispersed distinct EBV-positive neoplastic cells, and limited lymphoplasmacytic infiltrates. Immunohistochemically, the neoplastic cells showed variable staining for FDC markers (CD21, CD35, CD23, and SSTR2) and the fibroblastic marker SMA, with the staining ranging from very focal to extensive. The number of EBV-positive neoplastic cells ranged from 80 to 400/HPF. All cases showed variable expression of PD-ligand 1 (PD-L1) (CPS: 5-90). IgG4-positive cells ranged from rare up to 100/HPF. Interestingly, 2 cases satisfied the criteria proposed in a previous study, mimicking IgG4-related disease. EBV + IFDCS is an entity with an extremely wide morphologic spectrum and immunophenotype. Awareness of the spectrum of morphologic presentations of this rare tumor, specifically the lymphoma-like subtype and hemangioma-like subtype, is important for accurate diagnosis.

Primary lymphoma of the uterine cervix: a clinicopathologic study of 13 cases with review of additional 54 cases in the literature

Primary lymphoma of the uterine cervix (LUCX) is extremely rare, and its diagnosis is challenging. However, its clinicopathological features have not been well characterized. Thirteen primary LUCX patients were retrospectively studied, and 54 patients from the literature were reviewed. Primary LUCX was identified in 0.22% (13/6000) of patients with uterine cervical malignancies in our institution. The patients' median age was 51 years (range: 22-85 years). All patients had a bulk of neoplasms in the uterine cervix. The median tumour diameter was 6 cm (range: 1.5-10 cm). Approximately 78.0% (39/50) of the patients initially presented with irregular vaginal bleeding or discharge. Moreover, 86.7% (39/45) had Ann Arbor stage I or II. Diffuse large B-cell lymphoma, not otherwise specified, was the most common type, accounting for 85.0% (57/67) of primary LUCX cases. Follicular lymphoma (7.5%, 5/67), extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (4.5%, 3/67), mantle cell lymphoma (MCL), blastoid variant (1.5%, 1/67), and peripheral T-cell lymphoma (1.5%, 1/67) were occasionally observed. Three patients (7.1%, 3/42) with DLBCL, NOS died from the disease during the follow-up period. Their 5-year overall survival (OS) rate was 93.5%. The patient with MCL, blastoid variant in our present cohort died of the disease 33 months after diagnosis. Primary LUCX is an extremely rare condition. The clinical symptoms are non-specific. DLBCL, NOS is the most common histologic type, showing a favourable outcome with accurate diagnosis and timely and optimal treatment.

Inhibition of UBA6 by inosine augments tumour immunogenicity and responses

Anti-cancer immunity and response to immune therapy is influenced by the metabolic states of the tumours. Immune checkpoint blockade therapy (ICB) is known to involve metabolic adaptation, however, the mechanism is not fully known. Here we show, by metabolic profiling of plasma samples from melanoma-bearing mice undergoing anti-PD1 and anti-CTLA4 combination therapy, that higher levels of purine metabolites, including inosine, mark ICB sensitivity. Metabolic profiles of ICB-treated human cancers confirm the association between inosine levels and ICB sensitivity. In mouse models, inosine supplementation sensitizes tumours to ICB, even if they are intrinsically ICB resistant, by enhancing T cell-mediated cytotoxicity and hence generating an immunologically hotter microenvironment. We find that inosine directly inhibits UBA6 in tumour cells, and lower level of UBA6 makes the tumour more immunogenic and this is reflected in favourable outcome following ICB therapy in human melanomas. Transplanted mouse melanoma and breast cancer cells with genetic ablation of Uba6 show higher sensitivity to ICB than wild type tumours. Thus, we provide evidence of an inosine-regulated UBA6-dependent pathway governing tumour-intrinsic immunogenicity and hence sensitivity to immune checkpoint inhibition, which might provide targets to overcome ICB resistance.

The metabolic environment of tumours has wide-ranging effects on the anti-tumour immune response and the outcome of immune therapy. Authors show here that the purine metabolite inosine enhances tumour immunogenicity and thus immune checkpoint blockade therapy response by inhibiting the ubiquitin-activating enzyme UBA6 in tumour cells.

A retrospective study on the clinicopathological and molecular features of 22 cases of natural killer/T-cell lymphoma in children and adolescents

Natural killer/T-cell lymphoma (NKTCL) in children and adolescents is a rare type of T/NK cell neoplasms. The aim of the present study was to analyze the clinicopathological and genetic features of this rare entity of lymphoma. We evaluated the clinical, histopathological and molecular features of 22 young people with NKTCL, including 15 males and 7 females, with a median age of 15 years. The results revealed that the nasal site was the most involved region while non-nasal sites were observed in 27.3% out of all cases. The tumor cells were composed of small‑sized to large cells and 19 (86.4%) cases exhibited coagulative necrosis. The neoplastic cells in all patients were positive for CD3 and the cytotoxic markers. Nineteen (86.4%) cases were positive for CD56. Reduced expression of CD5 was observed in all available cases. CD30 was heterogeneously expressed in 15 (75.0%) cases. All 22 patients were EBV positive. Seven (36.8%) out of all the 19 patients during the follow-up died of the disease, and the median follow‑up period was 44 months. Moreover, patients treated with radiotherapy/chemotherapy showed significantly inferior OS compared with the untreated patients. High mutation frequencies were detected including KMT2C (5/5), MST1 (5/5), HLA-A (3/5) and BCL11A (3/5), which involved in modifications, tumor suppression and immune surveillance. These results suggest that NKTCL in children and adolescents exhibits histopathological and immunohistochemical features similar to the cases in adults. Active treatment is necessary after the diagnosis of NKTCL is confirmed. Furthermore, genetic analyse may provide a deep understanding of this rare disease.

Comparison of chemotherapy with or without asparaginase for extranodal nasal NK/T-cell lymphoma in children and adolescents

PURPOSE

As extranodal natural killer/T-cell lymphoma (ENKTL) occurs rarely in children and adolescents, standardized therapy is yet to be determined. This study aimed to describe the clinical features and determine the optimal chemotherapy regimen for childhood ENKTL.

METHODS

The treatment outcomes of radiotherapy combined with asparaginase-based (P-GEMOX or P-GMED) or asparaginase-absent chemotherapy regimens (CHOP, EPOCH, or NHL-BFM-90/95) in patients aged ≤18 years with newly diagnosed ENKTL from December 2006 to December 2018 were compared.

RESULTS

Among the 34 patients included in the study, 21 had stage I/II disease. The overall response rates of chemotherapy with or without asparaginase were 85.0% and 78.6%, respectively. With a median follow-up of 54 months, the 5-year event-free survival (EFS) rates of patients with stage I/II and III/IV disease were 66.2 ± 11.3% and 26.0 ± 12.8%, respectively (P = .027). In stage III/IV patients treated with asparaginase-based or asparaginase-absent regimens, the 5-year EFS rates were 40.0 ± 17.4% and 0%, respectively (P = .236). The 5-year EFS rates of stage III/IV patients who received or did not receive hematopoietic stem cell transplant were 66.7 ± 27.2% and 11.1 ± 10.5%, respectively (P = .054). In addition, chemotherapy-associated side effects were significantly less in patients treated with asparaginase-based regimens as compared to asparaginase-absent regimens in this cohort.

CONCLUSION

P-GEMOX and P-GMED regimens are effective and safe for treating childhood ENKTL.

Extranodal NK/T cell lymphoma, nasal type: An updated overview

Extranodal NK/T-cell lymphoma, nasal type (ENKTCL-NT) is an aggressive malignancy associated with Epstein-Barr virus infection, with a geographic and racial predilection for some Asian and Latin American countries. ENKTCL-NT manifests as a necrotic process affecting nasal or upper aerodigestive structures and, rarely, extranasal sites such as skin, and the gastrointestinal tract. ENKTCL-NT was characterized by its poor prognosis irrespective of clinical stage and therapy. However, during the last two decades, advances in its clinicopathologic, genetic and molecular characterization have been achieved, as have changes in the chemotherapy regimens that, in combination with radiotherapy, are significantly improving the survival of these patients, especially in initial stages. For these reasons, we present an overview of the historical background of ENKTCL-NT along with an updated review of its potential etiological factors, clinicopathologic and molecular features, as well as its prognostic models, current treatment protocols, and future directions on potential promising therapeutic approaches.

Primary extranodal natural Killer/T-cell lymphoma in a child in the colon: A case report

RATIONALE

Primary extranodal natural killer (NK)/T-cell lymphoma (ENKTL) rarely occurs in childhood and adolescence. To the best of our knowledge, ENKTL of childhood in the gastrointestinal (GI) tract has not been reported yet.

PATIENT CONCERNS

A 12-year-old Chinese boy complained of abdominal pain and persistent fever for 1 month.

DIAGNOSIS

Grossly an ulcerated tumor with perforation was located at the proximal ascending colon, 5 cm × 4 cm × 1.5 cm in diameter. The tumor was poorly circumscribed, tan-white and solid. Histological evaluation revealed medium-sized atypical lymphoid cells with large areas of necrosis distributed throughout all layers of the colon. Small blood vessels with destroyed walls were surrounded by lymphoid cells. Immunohistochemistry (IHC) highlighted tumor cells as strongly positive for CD3, CD56, CD5, CD2, CD8, CD4, CD43, T-cell restricted intracellular antigen 1 (TIA-1) and granzyme B. The proliferation index, measured by Ki-67 expression was high with 60%. The In situ hybridization (ISH) for EBER was positive. TCR was negative. Therefore, the final diagnosis was ENKTL of childhood in the colon.

INTERVENTIONS

The patient underwent right hemicolectomy and ileocolostomy.

OUTCOMES

We recommended further evaluation and treatment, but the patient and patient family rejected further treatment of his condition. The patient died within 1 month after being discharged from hospital as a result of his disease.

LESSONS

ENKTL of childhood in the GI tract is extremely rare. Due to the non-specific clinical symptoms, it is easy it is easy not to think of this differential diagnosis at early stage. If patients have GI symptoms, ENKTL cannot easily be ignored. It is necessary to diagnose ENKTL of childhood in the GI tract by morphology and immunohistochemistry, and to differentiate from the GI T-cell lymphomas. We hope this case may serve as a reference improving clinical diagnosis and treatment.

Clinicopathological and prognostic features of nasopharyngeal carcinoma in children and adolescents: A retrospective study of 196 cases in South China

Nasopharyngeal carcinoma (NPC) occurring in children and adolescence is extremely rare and till present there is a lack of understanding on their clinicopathological and prognostic features of this rare entity. For our study, data of 196 cases children and adolescents with NPC from the past 18 years at a high-volume cancer center from South China were retrospectively analyzed. Half of the evaluated NPC patients (83/166, 50.0%) were staged as Stage IVa disease, whereas 1.2% (2/166), 27.7% (46/166), 16.9% (28/166) and 4.2% (7/166) had Stage II, III, IVb and IVc disease, respectively. Serum EBV EA-IgA ≥1:10 and VCA-IgA ≥1:40 were found in 67.7% (113/167) and 76.6% (128/167) of the evaluated patients, respectively, whereas 56.8% (84/148) of the patients had plasma EBV DNA ≥1000 copies/mL. Histologically, all tumors were classified as nonkeratinizing squamous cell carcinoma (NK-SCC). Immunohistochemistrically, the expression of CK (AE1/AE3), P63, CK5/6 and P40 were observed in 100% (88/88), 93.2% (68/73), 84.1% (58/69) and 63.2% (12/19) of the detected cases, respectively. All cases show similar immunophenotype compared to that occurring in adult patients. All evaluated cases (71/71 100%) harbored EBER. Patients with plasma EBV DNA ≥1000 copies/mL and positive serum EBV antibodies had significantly inferior 3-year OS (88% vs 100%, P = .007) compared to other corresponding groups. The combination of EBV serology and plasma EBV DNA are useful to predict the outcome of patients with NPC in children and adolescents.

CD20-positive extranodal NK/T cell lymphoma: clinicopathologic and prognostic features

Extranodal natural killer (NK)/T cell lymphoma (ENKTCL) with aberrant CD20 expression is extremely rare. Here, we describe the clinicopathologic features of 11 CD20-positive ENKTCLs from three institutions in China along with a literature review. Membranous expression of CD20 was identified in 1.29% (11/851) of ENKTCLs. CD20-positive ENKTCLs primarily occurred in extra-nasal sites (72.2%, 13/18) rather than in the nasal cavity (27.8%, 5/18). Most evaluated patients (71.4%, 10/14) presented ENKTCL at advanced stage IV. The percentage of CD20-positive tumor cells ranged from 20 to 90%, and the CD20 staining intensity was dimmer in tumor cells than in normal B cells. Among four cases with multiple biopsies, three cases showed discordant expression of CD20 between the disseminated and primary lesions. All evaluated cases were negative for other B cell markers, including PAX5, CD79a, and CD19, except for one case that showed focally positive for CD79a. Patients with CD20-positive ENKTCL more frequently had advanced diseases (stage III/IV: 70% vs 17%, p = 0.001), with older age (median age at diagnosis: 60 years vs. 43.5 years, p = 0.006) and had inferior outcome (median survival: 18.7 moths vs 36.0 moths, p = 0.017) compared with CD20-negative cases. Four nonsynonymous single nucleotide variants (C > T) and one stop-gain mutation (C > T) in the exonic region of CD20 gene (MS4A1) were detected in one of seven cases with target region next-generation sequencing. Thus, ENKTCL with aberrant CD20 expression is rare, tends to occur in older patients, and is characterized by a highly aggressive clinical course and poor outcomes. The mechanism underlying the expression of CD20 in ENKTC still remains unknown.

Nitrosourea, etoposide and cyclophosphamide followed by autologous stem cell transplantation for pediatric lymphoma patients

Treatment outcomes in pediatric lymphoma have improved substantially over the past 2 decades; however, the prognosis for patients with high risk or relapsed disease remains poor. We evaluated outcomes of high-dose chemotherapy (HDC) and autologous stem cell transplantation (auto-SCT) in 56 pediatric lymphoma patients. Patients received nitrosourea (51 BCNU; 5 ACNU), etoposide, and cyclophosphamide (BEC; AEC). Median age at HDC/auto-SCT was 12 years (range 2-17 years). Forty-four patients underwent HDC/auto-SCT because they did not achieve complete remission after induction chemotherapy. Eight patients showed relapse and four NK/T-cell lymphoma patients also underwent HDC/auto-SCT. BCNU pneumonitis was diagnosed in nine (16.0%) patients. Eight (14.3%) relapsed after HDC/auto-SCT. Treatment-related mortality occurred in three cases. Five-year event-free survival and overall survival rates were 74.8% [72.7% non-Hodgkin's lymphoma (NHL); 83.3% Hodgkin's disease (HD); 72.7%] and 83.6% (81.6% NHL; 91.7% HD), respectively. HDC/auto-SCT with BEC or AEC regimen for pediatric high-risk lymphoma patients showed feasible outcomes. However, treatment modifications are warranted to reduce relapse and toxicity.

De Novo Testicular Extranodal NK/T-Cell Lymphoma: A Clinicopathologic Study of 21 Cases With Review of Additional 18 Cases in the Literature

Although the testis is not uncommonly involved during the course of disease in both nasal and non-nasal extranodal NK/T-cell lymphoma (ENKTCL), only a few cases presenting initially with a testicular mass have been previously reported. These have been documented as case reports, rather than as study series. Because of its rarity, the clinicopathologic features and the prognosis of de novo testicular ENKTCL have not been well characterized. Clinicopathologic features of 21 cases of de novo testicular ENKTCL from 3 institutions in China were retrospectively analyzed with review of an additional 18 cases from the literature. De novo testicular ENKTCL accounted for 0.72% (21/2906) of all ENKTCL during the study period. The median age of patients with de novo testicular ENKTCL was 45 years (range, 21 to 79 y). Most (90.9%) cases occurred in Asians. All patients initially presented with testicular swelling and most (91.9%) had unilateral testicular masses. The majority (73.0%) of patients presented at Ann Arbor stage I/II. Expression of CD56 was found in 92.1% (35/38) of the available cases. Interestingly, aberrant expression of CD20 was found in the tumor cells in 10.3% (4/39) of cases. The majority of patients with follow-up data (24/30, 80%) had extratesticular involvement during the follow-up period (median follow-up, 6 months; range, 0.5 to 87 mo). Preferential sites of extratesticular involvement included lymph nodes, skin, contralateral testis, bone marrow, spleen, adrenal gland, and central nervous system. Of the 30 patients with survival data, 70% (22/30) of patients died of the disease. The 2-year overall survival of patients with de novo testicular ENKTCL was 23%, and the median survival was 9.5 months. Patients that presented with B symptoms showed a trend toward inferior overall survival (P=0.095). No statistical significance was found between patients with stage I/II and stage III/IV (P=0.783). De novo testicular ENKTCL tends to disseminate early, shows extremely poor outcome, and should be recognized as a highly aggressive form of ENKTCL. A portion of cases show aberrant expression of CD20, and accurate diagnosis as well as timely and optimal treatment are very important.

High incidence of MYC rearrangement in human immunodeficiency virus-positive plasmablastic lymphoma

AIMS

MYC rearrangements are the main cytogenetic alterations in plasmablastic lymphoma (PBL). We aimed to investigate the relationship between MYC rearrangement and the clinicopathological features of PBL.

METHODS AND RESULTS

MYC rearrangements assessed in 13 unpublished single-centre PBL cases, and an additional 85 cases from the literature, with reported MYC rearrangement information individualised by patient, were reviewed. In Asia, PBL was much less commonly diagnosed in human immunodeficiency virus (HIV)-positive patients (27% versus 84%, P = 0.000), with older age (median age at diagnosis: 52 years versus 44 years, P = 0.046) and a lower EBV infection rate (56.8% versus 81.8%, P = 0.049), than in non-Asian regions. Overall, MYC rearrangements were identified in 44 of 98 (44.9%) PBL cases, and IGH was the partner in almost all available cases (30/31, 96.8%), as confirmed with a MYC-IGH fusion probe. The MYC rearrangement rate in HIV-positive cases (33/55, 60.0%) was significantly higher than that in HIV-negative cases (11/38, 28.9%, P = 0.003). Patients with MYC rearrangement showed a trend towards an inferior median survival time (9.6 months versus 15.7 months, P = 0.122) and 2-year overall survival (17% versus 32%, P = 0.238).

CONCLUSIONS

MYC rearrangement was frequently identified in PBL patients, and IGH was the partner gene in an overwhelming majority of MYC rearrangements. In addition, the MYC rearrangement rate was significantly higher in HIV-positive PBL patients than that in HIV-negative patients. MYC rearrangement may play an important role in the pathogenesis of HIV-positive PBL, but further studies are required to understand the underlying mechanisms.

Incidental lymphoma in lymph node dissection for carcinoma in the abdominopelvic cavity: a single-institution experience

Incidental detection of lymphoma in lymph node (LN) dissection for carcinoma is extremely rare. The occurrence and clinicopathological features of this rare condition have not been characterised. The medical records of 11,889 consecutive patients who underwent LN dissection for carcinoma in the abdominopelvic cavity were retrospectively reviewed. Among these patients, 11 had lymphomas detected in LN dissections and 7 had no previous history of lymphoma, representing an incidental detection rate of 0.06% (7/11889). The patients had a median age of 63 years (range, 48-69 years), and the male-to-female ratio was 1:2.5. The sites and histological types of the carcinoma were as follows: adenocarcinoma of the sigmoid colon (2 cases), endometrioid adenocarcinoma of the endometrium (2 cases), squamous carcinoma of the uterine cervix (1 case), adenocarcinoma of the stomach (1 case), and adenocarcinoma of the rectum (1 case). All incidental lymphoma cases (100%, 7/7) were low-grade B cell non-Hodgkin lymphoma (B-NHL), including 5 cases of follicular lymphoma (grades 1-2) and 2 cases of small lymphocytic lymphoma. The median follow-up interval was 39 months (5-65 months). All the patients were alive at the end of the follow-up period. Low-grade B-NHL can be incidentally detected during LN dissection for carcinoma in the abdominopelvic cavity. The subtype of incidental lymphoma is likely related to the epidemiology of lymphoma classes in the corresponding area. We should be aware of simultaneous occurrence of incidental lymphoma during lymphadenectomy for carcinoma.

Extranodal NK/T-Cell Lymphoma, Nasal Type in Guatemala: An 86-Case Series Emphasizing Clinical Presentation and Microscopic Characteristics

Extranodal NK/T-cell lymphoma, nasal type (ENKTCL-NT) is a lymphoid malignancy that mainly affects the nasopharynx and is associated with the Epstein-Barr virus (EBV). Increased incidence is seen in some Latin American and Asian countries. In this study, we describe a case series of 86 Guatemalan patients with ENKTCL-NT from a single diagnostic head and neck center. We emphasize the distinctive clinical, microscopic, and immunohistochemical (IHC) features, as well as EBV positivity by in situ hybridization (ISH). Most of the patients (90.6%) were of Mayan descent and low socioeconomic status (SES). Males were more often affected than females, comprising 68.3% of cases. Patient age ranged from 8 to 71, with a mean of 34.7 years. All cases arose in the upper aerodigestive tract and mainly presented as a rapidly progressive, necrotizing midfacial process affecting the nasal, nasopharyngeal, sinonasal, palatal, and oropharyngeal structures. Microscopically, ENKTCL-NT showed a diffuse polymorphic and atypical lymphoid infiltrate. Angiocentric and angiodestructive growth patterns were present with associated necrosis. Peripheral hyaline necrosis of blood vessels was a histologic hallmark. The ISH and IHC profiles included positivity of EBV, LCA, CD3, CD45RO, CD30 (focal in 39.2%), granzyme-B, TIA-1, perforin (in 82.3%), and CD56 (in 83.7%). CD20 was negative, and the Ki-67 index ranged from 70 to 90%. In Guatemala, this lymphoma is strongly associated with people of low SES and indigenous ethnicity. When affected, the palatal mucosa provides the best site to obtain a representative biopsy. Since ENKTCL-NT is highly aggressive, it is extremely important to recognize the spectrum of clinical presentations and microscopic features in order to avoid misdiagnosis and treatment delay.

Primary Nonanaplastic Peripheral Natural Killer/T-Cell Lymphoma in Pediatric Patients-An Unusual Distribution Pattern of Subtypes

Peripheral NK/T-cell lymphoma (PNKTCL) represents a group of uncommon diagnoses for children in Western countries, and studies have often necessitated multiple institutions to assemble enough cases. We retrospectively analyzed 11 cases of nonanaplastic PNKTCL in children over 19 years at our institution with comparison to several published large multi-institutional studies. Patients included 9 males and 2 females of white (5), Native American (3), and Hispanic (3) background with 6 cases of extranodal NK/T-cell lymphoma, nasal type (EN-NKTL, 54.6%), 3 cases of peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS, 27.2%), and 2 cases of systemic Epstein-Barr virus (EBV)-positive T-cell lymphoma of childhood (18.2%). Compared to the literature, our institution exceeded in frequency of total nonanaplastic PNKTCL (4.8% vs 0.9%-1.6%) with lesser relative incidence of PTCL-NOS (27.2% vs 42.9%-66.7%) and greater relative incidence of EN-NKTL (54.6% of cases vs 12.5%-47.6%), which significantly exceeded the literature's rate for Western institutions (13.5%). Potential influencing factors include population structure approximating those of non-Western countries with high EN-NKTL prevalence and the predisposition for EBV infection in this demography. These data suggest an uneven distribution of nonanaplastic PNKTCL in Western countries, and differential diagnoses may differ depending on practice location and associated patient population.

Extranodal NK/T-cell lymphoma in adolescents: imaging findings of a consecutive 7-year case series

Objectives

Extranodal NK/T-cell lymphoma is reportedly a rare but emerging type of lymphoma in adolescents. The present study was performed to specify its imaging characteristics.

Methods

Our hospital’s picture archiving and communication systems were searched from January 2009 to December 2016. We identified 13 patients aged <18 years with pathologically confirmed extranodal NK/T-cell lymphoma in the head and neck region. The computed tomography and magnetic resonance images were reviewed to summarize the imaging characteristics of extranodal NK/T-cell lymphoma in adolescents.

Results

The mean age at onset was 15.2 ± 1.46 years (range, 12–17 years) with a male:female ratio of 1.17:1.00. Most of the patients (n = 10) displayed nasal cavity and/or paranasal involvement. The tumor was homogeneous in both computed tomography and magnetic resonance images and showed slight enhancement. No calcification or liquefactive necrosis was observed. Adjacent structures were usually involved.

Conclusion

Suggestive imaging characteristics could acquaint specialists with extranodal NK/T-cell lymphoma in adolescents, facilitating improved early recognition of the diagnosis and helping to improve the patient’s outcome.

Extranodal Natural Killer/T-Cell Lymphoma, Nasal Type: Basic Science and Clinical Progress

Extranodal natural killer (NK)/T-cell lymphoma, nasal type (NNKTL) has very unique epidemiological, etiologic, histologic, and clinical characteristics. It is commonly observed in Eastern Asia, but quite rare in the United States and Europe. The progressive necrotic lesions mainly in the nasal cavity, poor prognosis caused by rapid local progression with distant metastases, and angiocentric and polymorphous lymphoreticular infiltrates are the main clinical and histologic features. Phenotypic and genotypic studies revealed that the lymphoma is originated from either NK- or γδ T-cell, both of which express CD56. In 1990, the authors first reported the presence of Epstein-Barr virus (EBV)-DNA and EBV-oncogenic proteins, and EBV has now been recognized to play an etiological role in NNKTL. in vitro studies revealed that a wide variety of cytokines, chemokines, and micro RNAs, which may be produced by EBV-oncogenic proteins in the lymphoma cells, play important roles for tumor progression in NNKTL, and could be therapeutic targets. In addition, it was revealed that the interaction between NNKTL cells and immune cells such as monocytes and macrophages in NNKTL tissues contribute to lymphoma progression. For diagnosis, monitoring the clinical course and predicting prognosis, the measurements of EBV-DNAs and EBV-micro RNAs in sera are very useful. For treatment with early stage, novel concomitant chemoradiotherapy such as DeVIC regimen with local radiotherapy and MPVIC-P regimen using intra-arterial infusion developed with concomitant radiotherapy and the prognosis became noticeably better. However, the prognosis of patients with advanced stage was still poor. Establishment of novel treatments such as the usage of immune checkpoint inhibitor or peptide vaccine with molecular targeting therapy will be necessary. This review addresses recent advances in the molecular understanding of NNKTL to establish novel treatments, in addition to the epidemiologic, clinical, pathological, and EBV features.

Acute Epstein-Barr virus-positive cytotoxic T cell lymphoid hyperplasia in the upper aerodigestive tract, mimicking extranodal natural killer/T cell lymphoma, nasal type

To describe the clinicopathological features of nine patients with acute Epstein-Barr virus (EBV)-positive cytotoxic T cell lymphoid hyperplasia (EBV+TLH) in the upper aerodigestive tract, in which initial findings led to a preliminary misdiagnosis of extranodal NK/T cell lymphoma, nasal type (ENKTL). A series of nine cases of EBV+TLH in one Chinese institution over a 9-year interval was retrospectively analyzed. Median age was 16 years (range 5-29 years) with a M:F ratio of 5:4. All patients were previously healthy with an acute onset period of < 1 month. Six patients (66%) presented with masses or polypoid protrusions in the upper aerodigestive tract. Nasopharyngeal symptoms, cervical lymphadenopathy, and fever were found in 89%, 78%, and 56% of patients, respectively. In seven cases, morphology mainly showed small-sized irregular cells and in two cases medium-to-large cells. In all cases, the cells diffusely expressed cytoplasmic CD3 and at least one marker for cytotoxic granules, but were negative for CD56. CD5 expression was detected in eight cases (8/9, 89%). In all cases, double staining for CD3 and EBER indicated that most T cells were infected with EBV. T cell receptor gene rearrangement was performed in five cases and all showed polyclonal results. All patients achieved complete remission within 1 month after diagnosis without any chemoradiotherapy and were followed up 19-124 months without recurrent disease. EBV+TLH in the upper aerodigestive tract is occasionally observed in China. The histopathologic features of EBV+TLH can mimic ENKTL. EBV+TLH should be taken into consideration as a potential diagnosis when the disease duration is short, spontaneous remission is achieved without intervention, and when histology shows infiltration with EBV-infected T lymphocytes.

Cutaneous Hematolymphoid and Histiocytic Proliferations in Children

This article focuses on cutaneous hematopoietic neoplasms that are more likely to be encountered in the pediatric age-group and includes both lymphoproliferative and histiocytic disorders. The cutaneous hematologic disorders in children have a different epidemiologic profile to what is seen during adulthood. Although mycosis fungoides is the most frequent form of cutaneous lymphoma in adults, it is very rare in children. Because lymphoblastic leukemias and lymphomas are more frequent in the pediatric setting, cutaneous leukemic infiltrates are relatively common in this age-group. Similarly, histiocytic disorders are more common in children, particularly Langerhans cell histiocytosis and juvenile xanthogranuloma. Notably, the histiocytic disorders have undergone significant modifications on their nomenclature in the basis of the molecular characteristics that are present in them. A summary of the most frequent cutaneous hematopoietic disorders in children will be discussed further in this review.

A distinct subtype of Epstein-Barr virus-positive T/NK-cell lymphoproliferative disorder: adult patients with chronic active Epstein-Barr virus infection-like features

The characteristics of adult patients with chronic active Epstein-Barr virus infection are poorly recognized, hindering early diagnosis and an improved prognosis. We studied 54 patients with adult-onset chronic active Epstein-Barr virus infection diagnosed between 2005 and 2015. Adult onset was defined as an estimated age of onset of 15 years or older. To characterize the clinical features of these adults, we compared them to those of 75 pediatric cases (estimated age of onset <15 years). We compared the prognosis of adult-onset chronic active Epstein-Barr virus infection with that of patients with nasal-type (n=37) and non-nasal-type (n=45) extranodal NK/T-cell lymphoma. The median estimated age of onset of these lymphomas was 39 years (range, 16–86 years). Compared to patients with pediatric-onset disease, those in whom the chronic active Epstein-Barr virus infection developed in adulthood had a significantly decreased incidence of fever (P=0.005), but greater frequency of skin lesions (P<0.001). Moreover, hypersensitivity to mosquito bites and the occurrence of hydroa vacciniforme were less frequent in patients with adult-onset disease (P<0.001 and P=0.0238, respectively). Thrombocytopenia, high Epstein-Barr virus nuclear antigen antibody titer, and the presence of hemophagocytic syndrome were associated with a poor prognosis (P=0.0087, P=0.0236, and P=0.0149, respectively). Allogeneic hematopoietic stem cell transplantation may improve survival (P=0.0289). Compared to pediatric-onset chronic active Epstein-Barr virus infection and extranodal NK/T-cell lymphoma, adult-onset chronic active Epstein-Barr virus infection had a poorer prognosis (P<0.001 and P=0.0484, respectively). Chronic active Epstein-Barr virus infection can develop in a wide age range, with clinical differences between adult-onset and pediatric-onset disease. Adult-onset chronic active Epstein-Barr virus infection is a disease with a poor prognosis. Further research will be needed.