High-dose chemotherapy with hematopoietic stem cell transplantation is effective for nasal and nasal-type CD56+ natural killer cell lymphomas

Sinonasal lymphoma: A primer for otolaryngologists

Objective

Sinonasal lymphomas are a rare entity that commonly present with nonspecific sinonasal symptoms and are often recognized immediately. Through this review, we aim to summarize important principles in diagnosis and treatment of sinonasal lymphomas, with the goal of disseminating the current knowledge of this under-recognized malignancy to otolaryngologists.

Methods

Systemic review using PRISMA guidelines of foundational scholarly articles, guidelines, and trials were reviewed focusing on clinical characteristics of key sinonasal lymphoma subtypes, along with available treatments in the otolaryngology, medical oncology, and radiation oncology literature.

Results

Sinonasal lymphoma are derived from clonal proliferation of lymphocytes at various stages of differentiation, of which diffuse large B-cell lymphoma (DLBCL) and extranodal natural killer/T-cell lymphoma (ENKTL) are the most common. Diagnosis and staging require biopsy with immunohistochemistry in conjunction with imaging and laboratory studies. Treatment is ever evolving and currently includes multi-agent chemotherapy and/or radiation therapy.

Conclusion

Otolaryngologists may be the first to recognize sinonasal lymphoma, which requires a comprehensive workup and a multidisciplinary team for treatment. Symptoms are nonspecific and similar to many sinonasal pathologies, and it is crucial for otolaryngologists to keep a broad differential.

Level of Evidence

5.

Allogeneic Hematopoietic Stem Cell Transplantation in Extranodal Natural Killer/T-cell Lymphoma

Objective

Extranodal NK/T-cell lymphoma (ENKL) is aggressive and resistant to chemotherapy and radiotherapy. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative treatment for high-risk lymphomas owing to its associated graft-versus-lymphoma (GVL) effect. However, its application to ENKL is limited. We aim to summarize the characteristics of allo-HSCT for ENKL and, more importantly, evaluate whether allo-HSCT could offer any benefits for ENKL.

Materials and Methods

A systematic review and data analysis were performed to evaluate the performance of allo-HSCT in the treatment of ENKL using studies obtained from PubMed, Medline, and Embase from January 2000 to December 2019 in the English language.

Results

A total of 136 cases from 17 eligible publications were included in this study. It was found that after allo-HSCT, with an average follow-up time of 34 months (range: 1-121 months), 37.5% (52) of 136 patients had acute graft-versus-host disease (GVHD) and 31.6% (43) had chronic GVHD. Furthermore, 35.3% (48) of the patients were reported to have relapsed, but 2 of those relapsed only locally and achieved complete remission (CR) again with additional irradiation, chemotherapy, and donor lymphocyte infusions for one and rapid tapering and discontinuation of cyclosporine for the other, earning more than one year of extra survival. Finally, of the 136 patients, 51.5% (70) died because of primary disease progression (42.9%), infection (20.0%), GVHD (11.4%), organ failure (7.1%), hemorrhage (4.3%), and other causes (not specified/unknown) (14.3%).

Conclusion

Allo-HSCT may be a treatment option for advanced or relapsed/refractory ENKL, but its role still requires more rigorous future studies.

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.

Primary testicular natural killer/T-cell lymphoma: A CARE-case report and review of literature

RATIONALE

Primary testicular natural killer (NK)/T-cell lymphoma is an extremely rare and highly aggressive lymphoid malignancy. At present, only 20 cases have been reported.

PATIENT CONCERNS

A 32-year-old Chinese man complained of discomfort and swelling of his right testicle for 3 months. Physical examination revealed a 10 × 10 × 9.5 cm mass on the right side of the scrotum area.

DIAGNOSES

Pathologic evaluation showed effacement of normal testicular parenchymal architecture by small-to-medium-sized lymphoid cells with irregular nuclear profiles, and immunohistochemical studies positively expressed CD2, CD56, cytoplasmic CD3, granzyme B, perforin, and TIA-1. Therefore, the patient was diagnosed with primary testicular NK/T-cell lymphoma.

INTERVENTIONS

The patient underwent CHOP (cyclophosphamide (CTX), pirarubicin (THP-ADM), vincristine (VCR), and prednisolone (PDN)) chemotherapy.

OUTCOMES

The patient relapsed 5 months after his initial presentation and died after an infection and gastrointestinal bleed.

LESSONS

Clinicopathological assessment of this rare case highlights the clinical and pathological features required to diagnose testicular NK/T-cell lymphoma. In addition, it highlights the dismal survival of these patients. We hope it may serve as a reference aiding prompt clinical diagnosis, which can hopefully improve the survival and quality of life of these patients.

[Primary colonic extranasal NK/T-cell lymphoma: about a case]

To better understand this cancer, we here report the case of a 43-year old patient diagnosed with localized and isolated primary colonic NK/T-cell lymphoma without associated enteropathy, treated wih 3 cycles of AspaMetDex with a poor response who died during treatment with a clinical picture of acute abdomen. Primary intestinal NK/T-cell lymphoma most commonly affects the young subject with poor prognosis. It is difficult to distinguish between intestinal NK/T-cell lymphoma and inflammatory or infectious intestinal disorders because of its non-specific clinical and endoscopic features. The histopathological and immunohistochemical data as well as the study of DNA allow to adjust the diagnosis and to classify this lymphoma according the European Enteropathy type T-cell lymphoma (ETL).

Characteristics and prognostic factors for head and neck non-Hodgkin's lymphoma in Chinese patients

BACKGROUND AND OBJECTIVES

The head and neck region is the second most frequent anatomical site of extranodal lymphomas. These tumours affect many individuals worldwide, justifying epidemiological studies in different countries. This study evaluated the characteristics, treatments and prognostic factors for non-Hodgkin's lymphoma of the head and neck in Chinese patients.

METHOD

The clinical manifestations, clinicopathological characteristics, multidisciplinary treatment and prognostic factors for 102 patients with extranodal non-Hodgkin's lymphoma of the head and neck were analysed retrospectively.

RESULT

The tonsil was the most commonly involved primary site, followed by the nasal cavity. The most common histological subtype was diffuse large B-cell lymphoma, followed by natural killer T-cell lymphoma. Patients receiving a combination of rituximab and chemotherapy did better than those receiving chemotherapy alone. Prognosis was significantly associated with both International Prognostic Index and histological subtype; the former was especially strongly associated with poor survival.

CONCLUSION

In this group of Chinese patients, diffuse large B-cell lymphoma was the most common pathological subtype, but the incidence of T-cell lymphomas was higher than that reported in the USA. Combined rituximab and chemotherapy led to better outcomes than chemotherapy alone. Prognosis depended on both International Prognostic Index and histological subtype.

Extranodal natural killer/T-cell lymphoma: current concepts in biology and treatment

Natural killer/T-cell (NK/T) lymphomas represent a group of rare tumors of NK and NK-T cells. The World Health Organization classifies NK-cell tumors into three types, extranodal NK/T-cell lymphomas (ENKL, nasal and non-nasal), NK-cell leukemias, and a blastic variant (CD4-positive, CD56-positive hematodermic neoplasms). We focus our review to the current concepts in biology and treatment of ENKL. Though considerable advances have been made in our understanding of NK-cell biology, malignant transformation including the role of Epstein-Barr virus, and prognosis, the rare nature of ENKL and its heterogeneity limit the ability to standardize therapy. Radiotherapy is fundamental to treatment of early-stage disease with a role for chemoradiotherapy among high-risk patients. The clinical course of advanced disease is highly aggressive with frequent chemotherapy resistance and a poor prognosis. Therapeutic approaches to advanced-stage or relapsed and refractory disease, including the appropriate sequence of chemotherapy, combined modality therapy, and stem cell transplantation is not well-established. International and multicenter clinical trials are needed for this rare and aggressive disease.

Clinical differences between nasal and extranasal natural killer/T-cell lymphoma: a study of 136 cases from the International Peripheral T-Cell Lymphoma Project

Among 1153 new adult cases of peripheral/T-cell lymphoma from 1990-2002 at 22 centers in 13 countries, 136 cases (11.8%) of extranodal natural killer (NK)/T-cell lymphoma were identified (nasal 68%, extranasal 26%, aggressive/unclassifiable 6%). The disease frequency was higher in Asian than in Western countries and in Continental Asia than in Japan. There were no differences in age, sex, ethnicity, or immunophenotypic profile between the nasal and extranasal cases, but the latter had more adverse clinical features. The median overall survival (OS) was better in nasal compared with the extranasal cases in early- (2.96 vs 0.36 years, P < .001) and late-stage disease (0.8 vs 0.28 years, P = .031). The addition of radiotherapy for early-stage nasal cases yielded survival benefit (P = .045). Among nasal cases, both the International Prognostic Index (P = .006) and Korean NK/T-cell Prognostic Index (P < .001) were prognostic. In addition, Ki67 proliferation greater than 50%, transformed tumor cells greater than 40%, elevated C-reactive protein level (CRP), anemia (< 11 g/dL) and thrombocytopenia (< 150 x 10(9)/L) predicts poorer OS for nasal disease. No histologic or clinical feature was predictive in extranasal disease. We conclude that the clinical features and treatment response of extranasal NK/T-cell lymphoma are different from of those of nasal lymphoma. However, the underlying features responsible for these differences remain to be defined.

Growth and apoptosis of human natural killer cell neoplasms: role of interleukin-2/15 signaling

Interleukin (IL)-15 plays an important role in the survival of human natural killer (NK) cells. We investigated IL-2/15 signaling in NK cell neoplasms from five patients and in five cell lines (NK-92, KHYG-1, SNK-6, HANK1 and MOTN-1) compared to mature peripheral NK cells from 10 healthy subjects. Apoptosis of NK cell lines was prevented by addition of IL-15 in vitro. Blocking IL-2/15Rbeta on IL-2-stimulated NK-92 cells resulted in reduced expression of Bcl-X(L) and phosphorylated Stat5, which paralleled early apoptosis without altering Bcl-2 expression. These data add IL-2/15Rbeta to the list of factors important for the survival of NK cell neoplasms.

Successful Treatment of Advanced Extranodal NK/T Cell Lymphoma with Unrelated Cord Blood Transplantation

Nasal natural killer (NK)/T cell lymphoma is a rare entity of non-Hodgkin's lymphoma which mostly occurs in East Asian countries. The advanced disease above clinical stage III is often refractory to the radiation and chemotherapies, remission is transient even if achieved, and median survival is about 12 months. Thus the prognosis of advanced NK/T cell lymphoma is generally poor, however, the promising results of allogeneic hematopoietic stem cell transplantation for advanced NK/T cell lymphoma have been recently reported. In most of these cases, stem cell sources were human leukocyte antigen (HLA) matched donors and alternative sources were seldom used. We report here a case of a 36-year-old woman who was diagnosed as having an extranodal NK/T cell lymphoma, nasal type. The patient achieved a complete remission after 2 cycles of chemotherapy including Carboplatin, Etoposide, Ifosfamide, and Dexamethasone, but 3-months later relapsed during the search for HLA-matched unrelated donors. She received unrelated cord blood transplantation (CBT) in the second remission achieved by a regimen containing L-asparaginase. The conditioning regimen was 12 Gy of total body irradiation, high-dose cytarabin and cyclophosphamide. FK506 and methotrexate were used for graft-versus-host disease (GVHD) prophylaxis. GVHD involving the intestine and the oral mucosa was observed, but improved without additional immunosuppressive therapies. The patient remains in remission 33 months after CBT. Cord blood thus could be an appropriate stem cell source for patients with advanced NK/T lymphoma who have no HLA matched donors.

Extranodal NK/T-cell lymphoma, nasal type

Extranodal NK/T-cell lymphoma, nasal type (ENKTCL), previously known as lethal midline granuloma is a distinct clinico-pathological entity associated with Epstein-Barr virus that typically causes destruction of the midface, palatal and orbital walls. In addition, ENKTCL can involve the skin, soft tissue, testes, gastrointestinal and upper respiratory tract. ENKTCL neoplastic cells express some T-cell associated antigens, most commonly CD2 and cytoplasmic CD3epsilon and, in favour of an NK-cell origin, CD56. Early stage disease may respond to radiotherapy alone, however late stage disease does not respond well to any available therapies. Overall, patients with ENKTCL have a cumulative probability of survival at 5 years ranging from 37.9% to 45.3%.

High-dose chemotherapy with autologous stem cell transplantation in extranodal NK/T-cell lymphoma: a retrospective comparison with non-transplantation cases

To determine the role of high-dose chemotherapy and autologous stem cell transplantation (HDC/ASCT) in extranodal NK/T-cell lymphoma patients, we conducted a retrospective analysis. In our previous study, we searched for patients who had received HDC/ASCT and identified 16 eligible patients and compared the treatment outcome with historical control group (n=246). Nine patients received HDC/ASCT in the first (CR1) or second complete remission (CR2), while seven patients received HDC/ASCT as salvage. Twelve of 16 patients achieved or maintained CR after HDC/ASCT. Among the 12 patients, five patients relapsed. Estimated 2-year overall survival (OS) and relapse-free survival (RFS) rates were 71.3+/-12.4% and 25.8+/-14.3%, respectively. There was a tendency of better survival in patients who received HDC/ASCT as compared to those who did not (P=0.091). In subset analysis, patients who underwent HDC/ASCT at CR (P=0.049) and patients with stage III or IV (P=0.001) had a favorable outcome. Patients with NKIPI 3,4 or EUNKTL, who underwent HDC/ASCT had more prolonged survival without statistical significance (P=0.055 and 0.056). In conclusion, HDC/ASCT may be considered as a treatment option for patients with extranodal NK/T-cell lymphoma, especially those in CR, with advanced disease (stage III/IV or EUNKTL) and high NKIPI scores.

Adoptive transfer of Epstein-Barr virus-specific cytotoxic T-lymphocytes for the treatment of angiocentric lymphomas

Angiocentric lymphoma, known as natural killer (NK)/T-cell non-Hodgkin's lymphoma, has been reported to be associated with the Epstein-Barr virus (EBV). We performed adoptive transfer of EBV-specific polyclonal T-cell lines in 3 patients with extranodal NK/T-cell lymphoma, nasal type, and evaluated the treatment for safety, immunologic reconstitution, and clinical outcomes. The tissue samples collected from the 3 patients were confirmed by polymerase chain reaction analysis to be EBV positive. In the cases of the first and second patients, EBV-transformed B-lymphoblastoid cell lines (LCLs) and T-cell lines were generated from peripheral lymphocytes of HLA-matched sibling donors. The third patient's T-cell lines were induced with autologous lymphocytes. Polyclonal T-cell infusion was carried out after high-dose radiotherapy because active relapsed disease remained in all of the patients. The first patient received 4 weekly infusions of 2 3 10(7) cells/m(2), and the second and third patients underwent treatment with 2 cycles of infusions of the same dosage. All T-cell lines showed >60% NK activity, cytotoxic T-lymphocyte (CTL) responses of >40% against autologous LCLs, and no CTL activity against patient-derived lymphoblasts. The level of cytotoxicity increased substantially in all patients after cell infusion. The 2 patients who received T-cell therapy twice had stabilized disease for more than 3 years. These safe treatments exhibited no severe inflammatory response, and no serious toxicity developed during T-cell therapy. Our findings demonstrate that adoptively transferred cells may provide reconstitution of EBV-specific CTL responses in patients with active relapsed angiocentric lymphoma. These results provide a rationale for the immunotherapy of angiocentric lymphoma.

NK/T-cell lymphomas ‘nasal type’: an Italian multicentric retrospective survey

OBJECTIVE

To evaluate the clinical characteristics and outcome of NK/T-cell lymphoma 'nasal type' developed in Italian patients.

PATIENTS

Between 1997 and 2004, 26 new cases of NK/T-cell lymphoma 'nasal type' were diagnosed in 10 Italian Hematology institutions.

RESULTS

All patients were Caucasian, male/female ratio was 19/7, with a median age of 50 years (range 20-80). In 23 cases presentation at the onset was in the nasal cavity or adjacent structures, in two cases the lymphoma onset with skin lesions was followed successively by rhynopharyngeal dissemination, while the remaining case had bone marrow and lymph node involvement followed by oro-pharyngeal involvement. Regarding the stage of disease: 12 patients were in stage I; six in stage II; eight in stage IV. Diagnosis was based on the finding of a NK/T-cell phenotype at the histological and immunophenotypic examination of oropharyngeal or cutaneous lesions. All patients but one were treated with chemotherapy, alone in nine cases or associated to radiotherapy in 14 cases; two patients had chemotherapy, radiotherapy and surgery, while one patient underwent only surgery. Chemotherapy was anthracycline-based in 17 out of 25 cases. In those patients in whom radiotherapy was performed, radiation dosages ranged between 36 Gy and 47.5 Gy, with a median dosage of 40 Gy. Nine patients (34%) were responsive to the treatments: six patients obtained a complete remission and other three a partial remission. The remaining 17 patients resulted refractory or presented a limited response to therapy. The median disease-free survival was 14 months and the median overall survival time was 9 months.

CONCLUSION

The results of this retrospective survey confirmed that NK/T-cell lymphoma 'nasal type' is a very rare lymphoma in the Italian population, and it is characterized by a very bad prognosis. Due to the rarity of this disease, a standardized therapeutic approach is lacking. More data are needed to know the epidemiology of this kind of lymphoma in Europe.

Hematopoietic stem cell transplantation for natural killer-cell lineage neoplasms

Neoplasms of natural killer (NK)-lineage are rare. Their prognosis is generally poor except for cases of solitary nasal NK-cell lymphoma. The NK-cell Tumor Study Group performed a survey in Japan on patients diagnosed between 1994 and 1998. Of 228 patients selected for analysis, 40 underwent HSCT (15 allografts and 25 autografts). The underlying diseases were myeloid/NK cell precursor acute leukemia (n = 4), blastic NK-cell lymphoma (n = 11), aggressive NK-cell leukemia (n = 3), and nasal-type extranodal NK-cell lymphoma (n = 22). At the time of HSCT, 22 patients were in complete remission (CR), 11 were in relapse, and seven were primary refractory. All patients received myeloablative conditioning regimens including total-body irradiation. Sixteen died of disease progression, and six of treatment-related causes. Overall, 4-year survival was 39% with a median follow-up of 50 months; this was significantly better than that of patients who did not undergo HSCT (21%, P = 0.0003). For patients transplanted in CR, the 4-year overall survival was 68%, which was significantly better than that of patients who went into CR but did not undergo HSCT (P = 0.03). These findings suggest that the HSCT is a promising treatment strategy for NK-cell lineage.

Intracranial Nasal Natural Killer/T-cell Lymphoma: Immunopathologically-Confirmed Case and Review of Literature

Advances in immunophenotypic profiling now permit characterization of natural killer/T-cell (NK/T-cell) lymphoma as distinct from other extranodal T- and B-cell Non-Hodgkin's lymphomas. NK/T-cell lymphoma presents most commonly in the nasal cavity. Disease progression to the central nervous system (CNS) is a rare phenomenon. We present here, to our knowledge, the first immunophenotypically-confirmed case of direct extension of nasal NK/T-cell lymphoma to the brain. In addition, we review the literature with respect to NK/T-cell lymphoma metastasis to the CNS. The overall prevalence of NK/T-cell lymphoma CNS metastasis is less than 3%. Although rare, CNS invasion portends a poor prognosis, emphasizing the importance of early and accurate immunophenotype profiling and the need for novel, aggressive therapy.

Allogeneic haematopoietic stem cell transplantation as a promising treatment for natural killer-cell neoplasms

The efficacy of allogeneic haematopoietic stem-cell transplantation (allo-HSCT) for natural killer (NK)-cell neoplasms is unknown. We investigated the results of allo-HSCT for NK-cell neoplasms between 1990 and 2003 through questionnaires. After reclassification by a haematopathologist, of 345 patients who underwent allo-HSCT for malignant lymphoma, 28 had NK-cell neoplasms (World Health Organization classification): extranodal NK/T-cell lymphoma (n=22), blastic NK-cell lymphoma (n=3), and aggressive NK-cell leukaemia (n=3). Twelve were chemosensitive and 16 chemorefractory. Twenty-two had matched-related donors. Stem-cell source was bone marrow in eight and mobilised peripheral blood in 20. Conditioning regimens were myeloablative (n=23) and non-myeloablative (n=5). Grade 2-4 acute graft-versus-host disease (GVHD) and chronic GVHD developed in 12 and 8 respectively. Eight died of disease progression, three of infection, two of acute GVHD, one of veno-occlusive disease, one of interstitial pneumonitis, and one of thrombotic microangiopathy. Two-year progression-free and overall survivals were 34% and 40% respectively (median follow-up, 34 months). All patients who did not relapse/progress within 10 months achieved progression-free survival (PFS) during the follow-up. In multivariate analysis, stem cell source (BM versus peripheral blood; relative risk 3.03), age (>or=40 years vs. <40 years; relative risk 2.85), and diagnoses (extranodal NK/T-cell lymphoma versus others; relative risk 3.94) significantly affected PFS. Allo-HSCT is a promising treatment for NK-cell neoplasms.

Natural killer cell neoplasms

Lymphoid neoplasms that are derived from natural killer (NK) cells are uncommon but distinct clinicopathologic disease entities. Three types have been recognized and categorized in the latest World Health Organization classification: extranodal NK cell lymphoma, nasal-type; aggressive NK cell leukemia; and blastic NK cell lymphoma. All NK tumor cells express the NK cell marker CD56, but they lack the expression of surface CD3 and the rearrangement of T-cell receptor genes, which distinguish them from T-lymphoid neoplasms. There is also a strong association with the Epstein-Barr virus, except in blastic NK cell lymphoma. Extranodal involvement by the NK cell tumor is common, especially in the nasal cavity, the skin, and the gastrointestinal tract. All 3 NK cell neoplasms are characterized by aggressive clinical course and poor response to treatment. Although the optimal treatment modality remains to be determined, good initial response to combined radiation therapy and chemotherapy has been observed in localized disease. Further studies in the basic biology of the NK cell and the pathology of NK cell neoplasms may shed light on the development of newer and more effective therapy.

Primary nasal lymphoma, NK/T-cell type: report of two cases with similar presentation but different outcome

Two cases of natural killer (NK)/T-cell primary nasal lymphoma with similar clinical presentations are reported, for comparison and contrast, to highlight the clinical issues and challenges posed by this unusual disease, its aggressiveness being matched only by its rarity. Presenting as a lesion in the nasal cavity with histological features of malignant lymphoma, primary nasal lymphoma is an uncommon extranodal lymphoma, which poses problems in both diagnosis and management. In people of oriental descent, the common cell subtype is NK/T-cell. Although it is generally thought that combination treatment with chemotherapy and radiation is the best management for early stage non-Hodgkin's lymphoma (NHL), there is still debate as to whether combined therapy is optimal treatment for this particular subtype of NHL, given that it responds less well to conventional chemotherapy. Herein we report two patients to illustrate these controversies.

Leukemia and lymphoma of natural killer lineage cells

Natural killer (NK) cells are lymphocytes with a large granular lymphocyte morphology, a CD3- CD56+ phenotype, a non-major histocompatibility complex-restricted cytotoxicity, and germline configuration T-cell receptor genes. NK cell lineage tumors originate from either precursor NK cells or mature NK cells. Tumors originating conceivably from precursor NK cells include myeloid/NK cell precursor acute leukemia, precursor NK cell acute lymphoblastic leukemia, and blastic NK cell lymphoma. However, because the developmental pathway of normal NK cells and the characteristics of these NK precursors are not fully understood, the definition and characterization of the tumors are only provisional. Tumors of mature NK cell origin include aggressive NK cell leukemia/lymphoma, nasal-type NK cell lymphoma, and chronic NK lymphocytosis, but the last disorder seems to be reactive in most cases. Because NK cell tumors are rare and difficult to manage, vigorous studies are required for their understanding and management.

Primary NK/T cell lymphoma of the testis. A case report and review of the literature

We report a case of aggressive 'nasal type' natural killer (NK)/T cell lymphoma initially presenting as a testicular tumor in a Korean man, which quickly took a fatal course by widespread dissemination. Histologically, the testicular mass showed a diffuse dense infiltrate of medium-sized and atypical large lymphoid cells with angiocentric and angiodestructive infiltration and areas of coagulative necrosis on hematoxylin-eosin stained sections. Immunophenotyping by immunohistochemistry yielded surface markers consistent with NK/T cell lymphoma. The Epstein-Barr virus genome was detected by in situ hybridization. During involved-field irradiation and chemotherapy following radical orchiectomy, the tumor disseminated shortly to the skin and soft tissue of his anterior chest wall and central nervous system (CNS). Identical lymphoid infiltrates were present in the patient's skin. CNS involvement was interpreted as having a leptomeningeal seeding. To the best of our knowledge, this is the 9th reported case of confirmed NK/T cell lymphoma arising from the testis. Relevant literature is reviewed, and the clinicopathologic features, natural history, and treatment options for primary testicular NK/T cell lymphoma are discussed.