Natural killer cell neoplasm: biology and pathology

Extranodal natural killer/T-cell lymphoma with hepatosplenic involvement: a retrospective study of a consecutive 14-year case series

Extranodal natural killer/T-cell lymphoma (ENKTL) with hepatosplenic involvement is rare, accounting for approximately 0.2% of ENKTL cases. The clinicopathologic features of ENKTL with hepatosplenic involvement are still poorly understood. Seven cases of ENKTL with hepatosplenic involvement were investigated retrospectively by clinical features, pathology, immunophenotype, genotype, Epstein-Barr virus (EBV) status, and survival analysis. The median age was 36 years; three patients (3/7) had a history of primary nasal ENKTL. Six cases (6/7) presented liver or spleen structures that were replaced by neoplasms, and the neoplastic cells displayed diffuse infiltration; one case (1/7) displayed neoplastic cells scattered in hepatic sinuses and portal areas. The cellular morphology and immunohistochemical features were similar to those of ENKTL involving other sites. Follow-up data were available in five of the seven patients. All five patients received first-line chemotherapy based on L-asparaginase. Three patients died, and two were still alive by the last follow-up. The median overall survival (OS) was 21 months. ENKTL with hepatosplenic involvement is rare, regardless of whether it is initial or secondary. There are two histopathologic patterns of ENKTL with hepatosplenic involvement, and L-asparaginase-based chemotherapy combined with AHSCT might yield good efficacy. Morphological features of ENKTL in the spleen and liver A The architecture of the spleen was affected, and dense infiltration of the neoplastic cells was observed in the left part; B Focal infiltration of the neoplastic cells was located in the red pulp; C Dense infiltration of the neoplastic cells in the liver, accompanied by fatty change of hepatocytes and congestion; D More neoplastic cells accumulated in sinusoidal region.

A Case Report on Aggressive Natural Killer Cell Leukemia in a Pediatric Patient

Aggressive natural killer cell leukemia (ANKL) is a rare neoplastic malignancy, especially in pediatric populations with very few cases reported in the literature. It commonly presents with a rapidly declining clinical course and has a median survival of two months. We report the case of a 15-year-old female who presented with fever, hepatosplenomegaly, hemophagocytosis, and disseminated intravascular coagulation (DIC). The patient was ultimately diagnosed with ANKL but died after developing multiorgan failure and DIC prior to the initiation of any treatment. In this case report, we review and discuss the literature concerning the diagnosis and treatment of ANKL in pediatric patients.

Comparison of Diagnostic Cytomorphology of Natural Killer/T-Cell Lymphoma (Nasal Type) in Conventional Smears, Liquid-Based Preparations, and Histopathology

Natural killer (NK)/T-cell lymphoma is formally referred to as extranodal NK/T-cell lymphoma, nasal type (ENKTCL), in the 2008 and 2016 World Health Organization (WHO) classifications. NK/T-cell lymphoma, nasal type, is a rare but clinically important lymphoid neoplasm. It is the predominant type of extranodal lymphoma associated with the Epstein–Barr virus (EBV). NK/T-cell lymphoma is marked by a wide cytomorphological spectrum. The cytological findings may be so subtle that NK/T-cell lymphoma could possibly be easily overlooked. Here, we report a case of NK/T-cell lymphoma involving the sinonasal region with lymph node involvement. Fine needle aspiration of the neck lymph node and punch biopsy of the nasal mucosa were performed. The diagnosis of NK/T-cell lymphoma was confirmed based on pathological and immunohistochemical analyses, as well as in situ hybridization for EBV-encoded mRNA (EBER). The present case report underlines the importance of prompt clinicopathological assessment in suspected cases. The comparison of cytomorphologic features of NK/T-cell lymphoma in various specimens is presented.

Chronic active Epstein-Barr virus infection associated with hemophagocytic syndrome and extra-nodal natural killer/T-cell lymphoma in an 18-year-old girl: A case report

RATIONALE

Chronic active Epstein-Barr virus infection (CAEBV) associated with hemophagocytic syndrome (HPS) and extra-nodal natural killer (NK)/T-cell lymphoma (ENKL) is a rare life-threatening disorder. This disease is easily misdiagnosed because of its varied presentations.

PATIENT CONCERNS

An 18-year-old girl was admitted to our hospital with a history of edema in the lower limbs and intermittent fever lasting for more than 1 month. At admission, she had severe liver injury of unknown etiology. Laboratory test results revealed pancytopenia, hyperferritinemia, hypertriglyceridemia, and hypofibrinogenemia. Results of serologic tests for EBV were positive. Results of a skin biopsy indicated EBV-positive NK/T-cell lymphoma, and bone marrow aspiration revealed focal hemophagocytosis and atypical lymphoid cells.

DIAGNOSIS

On the basis of these findings, we diagnosed the case as extra-nodal NK/T-cell lymphoma-associated HPS (natural killer/T-cell lymphoma-associated hemophagocytic syndrome), which is commonly induced by CAEBV.

INTERVENTIONS

Treatment consisted of general management of hepatitis, supplemented with albumin and empirical antibiotic therapy.

OUTCOMES

The patient died from massive gastrointestinal hemorrhage a week after she was discharged from the hospital.

LESSONS

ENKL and HPS present with varied features and are generally fatal; therefore, clinicians should proceed with caution in suspected cases. HPS should be considered when the patient presents with fever, hepatosplenomegaly, pancytopenia, and liver failure. When HPS is suspected, clinicians should determine the underlying cause, such as severe infection, including infection with viruses such as EBV; genetic predisposition; or underlying malignancies, especially lymphoma because of its strong association with HPS.

Blastic plasmacytoid dendritic cell neoplasm: A case report and literature review

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a clinically aggressive tumor, which frequently presents as cutaneous lesions and subsequently progresses to bone marrow (BM) involvement and leukemic dissemination. BPDCN is a rare entity that belongs in the same class as acute myeloid leukemia-associated precursor neoplasms, according to the 2008 World Health Organization classification. The present study reported the case of a 26-year-old female who presented with evident thrombocytopenia, leukocytosis and anemia, but without skin lesions. The results of peripheral blood, BM smear and BM biopsy examinations detected numerous blastic or abnormal cells. In addition, flow cytometric analysis of BM demonstrated the presence of plasmacytoid dendritic cell-neoplastic precursor cells (CD4+, CD56+, CD123+, CD304+ and human leukocyte antigen-DR+ phenotype).

Extranodal hematopoietic neoplasms and mimics in the head and neck: an update

The head and neck region is a common site for extranodal lymphomas, second only to the gastrointestinal tract; and 12% to 15% of all head and neck tumors are lymphomas. Non-Hodgkin lymphomas are most common, and Hodgkin lymphoma occurs rarely at extranodal sites in the head and neck. Most non-Hodgkin lymphomas of the head and neck region are of B-cell lineage, and the Waldeyer ring is the most common site. Head and neck lymphomas have distinctive epidemiological and clinicopathologic features, including an association with immunosuppression, infectious organisms, or autoimmune disorders; site-specific differences (eg, thyroid gland versus ocular adnexa) for common lymphomas, such as extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue; and genetic differences that provide insights into etiology. Furthermore, the diagnosis of non-Hodgkin lymphomas at extranodal sites implies differences in prognosis and therapeutic implications with lymphomas at nodal sites. In this review, we discuss various types of non-Hodgkin lymphomas and Hodgkin lymphoma, focusing on unique aspects related to the head and neck region. We also discuss a number of newer entities that are clinically indolent as well as mimics of lymphoma that can occur in the head and neck region, including infectious mononucleosis, Kikuchi-Fujimoto disease, Kimura disease, Castleman disease, and immunoglobulin G4-related disease.

Primary central nervous system extranodal NK/T cell lymphoma, nasal type, with antecedent hemophagocytic syndrome in a child

Primary central nervous system (CNS) extranodal natural killer (NK)/T-cell lymphoma, nasal type (NKTCL), is an exceedingly uncommon entity. Here, we present a case of CNS NKTCL that manifested initially as hemophagocytic syndrome 4 months earlier in a 13-year-old girl. Histological examination revealed the cerebellum mass was composed of large-sized and atypical tumor cells, with an angiocentric and angiodestructive growth pattern and prominent necrosis. The tumor cells exhibited marked pleomorphism with conspicuous nucleoli and prominent mitotic activity. Immunohistochemical staining showed the tumor cells were positive for CD45, CD2, CD3ε, CD30, CD43, CD56, and granzyme B. Epstein-Barr virus--encoded ribonucleic acid was expressed in almost all of the nuclei of the lymphoma cells. The T-cell receptor γ chain gene rearrangement study showed no evidence of a clonal rearrangement. The patient was treated with etoposide and dexamethasone and died a few days after the operation. As far as we know, this case is the 1st pediatric and female patient of primary CNS NKTCL with antecedent hemophagocytic syndrome, which highlights the clinical data and is helpful for the diagnosis of this tumor.

Pathology of the liver sinusoids

The hepatic sinusoids comprise a complex of vascular conduits to transport blood from the porta hepatis to the inferior vena cava through the liver. Under normal conditions, portal venous and hepatic artery pressures are equalized within the sinusoids, oxygen and nutrients from the systemic circulation are delivered to the parenchymal cells and differentially distributed throughout the liver acini, and proteins of liver derivation are carried into the cardiac/systemic circulation. Liver sinusoid structures are lined by endothelial cells unique to their location, and Kupffer cells. Multifunctional hepatic stellate cells and various immune active cells are localized within the space of Disse between the sinusoid and the adjacent hepatocytes. Flow within the sinusoids can be compromised by physical or pressure blockage in their lumina as well as obstructive processes within the space of Disse. The intimate relationship of the liver sinusoids to neighbouring hepatocytes is a significant factor affecting the health of hepatocytes, or transmission of the effects of injury within the sinusoidal space. Pathologists should recognize several patterns of injury involving the sinusoids and surrounding hepatocytes. In this review, injury, alterations and accumulations within the liver sinusoids are illustrated and discussed.

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.

Resveratrol induces cell cycle arrest and apoptosis in malignant NK cells via JAK2/STAT3 pathway inhibition

Natural killer (NK) cell malignancies, particularly aggressive NK cell leukaemias and lymphomas, have poor prognoses. Although recent regimens with L-asparaginase substantially improved outcomes, novel therapeutic approaches are still needed to enhance clinical response. Resveratrol, a naturally occurring polyphenol, has been extensively studied for its anti-inflammatory, cardioprotective and anti-cancer activities. In this study, we investigated the potential anti-tumour activities of resveratrol against the NK cell lines KHYG-1, NKL, NK-92 and NK-YS. Resveratrol induced robust G0/G1 cell cycle arrest, significantly suppressed cell proliferation and induced apoptosis in a dose- and time-dependent manner for all four cell lines. In addition, resveratrol suppressed constitutively active STAT3 in all the cell lines and inhibited JAK2 phosphorylation but had no effect on other upstream mediators of STAT3 activation, such as PTEN, TYK2, and JAK1. Resveratrol also induced downregulation of the anti-apoptotic proteins MCL1 and survivin, two downstream effectors of the STAT3 pathway. Finally, resveratrol induced synergistic effect on the apoptotic and antiproliferative activities of L-asparaginase against KHYG-1, NKL and NK-92 cells. These results suggest that resveratrol may have therapeutic potential against NK cell malignancies. Furthermore, our finding that resveratrol is a bonafide JAK2 inhibitor extends its potential benefits to other diseases with dysregulated JAK2 signaling.

Aggressive natural killer cell leukemia: therapeutic potential of L-asparaginase and allogeneic hematopoietic stem cell transplantation

We conducted a retrospective Japan-Korea multicenter study to better elucidate the clinicopathologic features and therapeutic modalities for aggressive natural killer cell leukemia (ANKL). A total of 34 patients were analyzed. The median age of the patients was 40 years. Among the patients in the study, four had a history of Epstein-Barr virus-related disorders. Three types of ANKL cells were categorized according to their morphological features. Leukemic cells were below 20% in both peripheral blood and bone marrow of 11 patients. The clinical characteristics and prognoses of these 11 patients did not differ significantly from those of the others. As an initial therapy, l-asparaginase chemotherapy resulted in a better response. A total of six patients received allogeneic hematopoietic stem cell transplantation (HSCT) and two received autologous HSCT, with all in non-complete remission (CR). After HSCT, four with allogeneic and one with autologous HSCT reached CR. Median survival of all patients was 51 days. Median survival for the patients with and without HSCT were 266 and 36 days, respectively. A total of two patients with allogeneic HSCT were alive and in CR. All patients without HSCT died of ANKL. The use of L-asparaginase was indicated as a factor for longer survival (HR 0.33, 95% confidence interval; 0.13-0.83, P = 0.02). Early diagnosis of ANKL, l-asparaginase-based chemotherapy and allogeneic HSCT might lead to improved patient outcomes.