Bone marrow is involved in less than 10% of patients with nasal-type NK/T cell lymphoma at initial diagnosis

To evaluate the frequency of bone marrow involvement by nasal-type NK/T cell lymphoma, we retrospectively studied biopsy specimens from 40 patients by EBV in situ hybridization (ISH). Three patients had marrow involvement at initial diagnosis (7.5%). In one patient (1/40, 2.5%), the disease in bone marrow was recognized by routine morphological assessment, while two other patients had minimal involvement of lymphoma cells which was recognized only by EBV in situ hybridization (2/40, 5%). Two patients had a disseminated disease at diagnosis and died 6 days and 214 days after diagnosis. One patient had diffuse colonic lesion and died 82 days later. In conclusion, marrow involvement in nasal NK/T cell lymphoma is infrequent at initial diagnosis, and EBV ISH is a useful technique for identifying the minor subgroup of patients which have easily overlooked neoplastic involvement.     

Histological and immunophenotypic profile of nasal NK/T cell lymphomas from Peru: high prevalence of p53 overexpression.

Nasal NK/T-cell lymphoma is a unique form of lymphoma highly associated with Epstein-Barr virus (EBV). These lymphomas are rare in Western populations and much more prevalent in some Asian and Latin American countries. Although there are several sizable studies from Asian countries, the same is not true from South America. The aim of this study was to analyze a series of 32 cases of nasal T-cell lymphoma from Peru and to further extend the characterization of this disease. Immunohistochemistry was performed on paraffin sections using the following antibodies: CD20 (L26), CD45RO, CD3, Ki67, CD57, CD56, TIA-1, bcl-2, and p53. The presence of EBV was investigated with immunohistochemical analysis for latent membrane protein (LMP)-1 and in situ hybridization using an antisense riboprobe to EBER 1. The 32 patients included 18 men and 14 women (M:F ratio, 1.2:1), with a median age of 43 years (11 to 72). Three categories were identified: (1) Nasal NK/T cell lymphomas (28 cases): The morphology ranged from small or medium-sized cells to large transformed cells. Necrosis was present in 86% of the cases, and angioinvasion was seen in 36% of the cases. All cases were positive for CD45RO, CD3, and for TIA-1. CD56 was positive in 21 of 27 cases (78%), and CD57 was negative in all cases. EBER 1 positivity was identified in most of the tumor cells in 27 of 28 cases (96%), including the six cases in which CD56 was negative. Overexpression of p53 was detected in 24 cases (86%). (2) Blastic NK cell lymphoma (1 case): The neoplastic cells resembled those of lymphoblastic lymphoma. CD56 and CD45RO were positive; TIA-1, TdT, and EBER-1 were negative. (3) Peripheral T-cell lymphoma (PTCL) unspecified (3 cases): CD56, TIA-1, and EBER-1 were negative. Nasal lymphomas from Peru with a T cell phenotype are predominantly EBV-associated NK/T cell lymphomas, similar to those described in Asian countries. The expression of CD56, TIA-1, and EBER-1, in combination, are very useful markers for the diagnosis of nasal NK/T cell lymphoma in paraffin-embedded tissue. The differential diagnosis of T-cell lymphomas in the nasal region should include rare cases of PTCL unspecified and the blastic variant of NK cell lymphoma. P53 is overexpressed in 86% of the cases. The significance of this finding with regard to clinical behavior and prognosis remains to be determined.     

Nasal NK/T cell lymphoma in Taiwan: a clinicopathologic study of 22 cases, with analysis of histologic subtypes, Epstein-Barr virus LMP-1 gene association, and treatment modalities

Nasal NK/T cell lymphoma is a distinctive type of extranodal lymphoma with an unique immunophenotype and a strong association with Epstein-Barr virus (EBV). It is one of the common extranodal lymphomas in Taiwan. We studied 22 cases of nasal NK/T cell lymphoma to characterize their clinicopathologic features and to explore the possible differences between histologic subtypes and their clinical behavior as well as the prevalence of 30-base pair (bp) deleted latent membrane protein-1 (LMP-1) gene of the EBV. They consisted of 5 cases of small cell type (SC), 6 cases of medium-sized cell type (MC), 6 cases of large cell type (LC), and 5 cases of pleomorphic cell type (PC). Twelve patients were men and 10 were women (1.2 to 1), and their ages ranged from 34 to 75 years with a median age of 55.5 years. The median ages of the LC type and PC type were older than the other 2 types. No other clinical features differed significantly among the 4 subtypes. Nasal obstruction was the most common initial presenting symptom. All but 1 case had stage IE disease at the time of diagnosis. Five cases developed extranasal involvement and skin was the most common site. No bone marrow involvement was detected. The majority of patients received local radiotherapy and chemotherapy. Local irradiation was more effective than chemotherapy alone. We achieved an overall survival of 63.6% at 5 years as estimated by the Kaplan-Meier analysis, which was better than other series. All cases displayed an immunophenotypic profile of CD3(epsilon)+, CD20-, CD56+, and TIA-1+ except that 1 case was CD3(epsilon)-. Fourteen of 22 cases (64%) expressed LMP-1. Nine cases of various cell types (41%) were also CD30+. Among the 4 histologic subtypes, the SC type differed from the other types by the absence of angiodestruction and necrosis, although angioinvasive growth was seen in 2 of them. Pseudoepitheliomatous hyperplasia was seen in only 3 cases of the SC type, and all 5 cases of the SC type were CD30-. No statistical difference in survival was found among the 4 histologic subtypes or between CD30+ and CD30- cases. All 22 cases were positive for EBV by polymerase chain reaction and Epstein-Barr virus early RNA (EBER) in-situ hybridization. A high prevalence rate of 86% (19/22) of the 30-base pair (bp) deleted LMP-1 gene was found, but 81.5% (22/27) of the EBV-positive control reactive lymphoid tissues also had the 30-bp deleted LMP-1 gene. Therefore, the high prevalence of the 30-bp deleted LMP-1 gene found in NK/T cell lymphoma could be due to the high prevalence of the deleted variant in this geographic region. However, it remains possible that the high prevalence of the deleted LMP-1 gene contributed to the increased incidence of EBV-associated nasal NK/T cell lymphoma in Taiwan.     

Epstein-Barr virus in nasal T-cell lymphomas (polymorphic reticulosis/midline malignant reticulosis) in Western China

Polymorphic reticulosis (PR) or midline malignant reticulosis (MMR) is considered to be malignant, or at least pre-malignant T-cell proliferations of the nose or midline area. Recent reports of small series of nasal T-cell lymphomas have shown a strong association with Epstein-Barr virus (EBV). Furthermore, a peculiar phenotype is described, with expression of CD56 and not of CD3, suggesting a possible origin from natural killer (NK) cells. We have analysed a series of 38 cases of PR/MMR for the presence of EBV by in situ hybridization (ISH) of the EBV-encoded RNAs 1 and 2 (EBER). Twenty cases were tested for expression of EBV-encoded latent membrane protein 1 (LMP-1). Special attention was also paid to the expression of CD3 and the NK cell-related marker CD56. Thirty-two cases (84 per cent) showed positive EBER ISH. In 5 of 20 cases, LMP-1 expression was detected. In three cases, a few scattered cells were positive, and in two cases, LMP-1 was detected in clusters of atypical cell. Most of the neoplasms showed expression of CD3 (89 per cent) and in 27 cases (71 per cent), CD56 was detected. These results are consistent with an aetiopathogenetic role for EBV in most, but not all, cases of PR/MMR. Our findings are less supportive of a major role for LMP-1 in tumour genesis. CD3 expression in most of the cases of PR/MMR underlines the T-cell origin of these neoplasms, often with aberrant expression of CD56.     

Therapeutic outcome of Epstein-Barr virus positive T/NK cell lymphoma in the upper aerodigestive tract

Expression of the natural killer (NK) cell antigen CD56 is uncommon in malignant lymphoma, but when it is, it is almost exclusively of the non-B cell lineage and show a preference for the nasal and nasopharyngeal region. T/NK cell lymphoma is known to be aggressive and refractory to treatment. It is highly associated with the Epstein-Barr Virus (EBV), but clinical investigations are rarely reported, that is until recently. We report here, on the clinical features and therapeutic outcomes of patients with T/NK cell lymphomas and its association with EBV. We reviewed fifty-four cases with peripheral T cell lymphomas in the upper aerodigestive tract between Jan. 1987 and Aug. 1998 from the Severance Hospital, Yonsei University College of Medicine. The diagnosis of T/NK cell lymphoma was made according to the expression of the NK cell markers, CD56 antigen and cytoplasmic CD3epsilon, in tumor specimens, by immunohistochemistry. Epstein-Barr early region (EBER) RNA was detected using in situ hybridization on paraffin-embedded sections. Among the 54 cases with malignant lymphomas occurring in the upper aerodigestive tract, 20 had T/NK cell lymphoma (37%). The primary sites of T/NK cell lymphomas were the nasal cavity, 12 cases (60%), the tonsils, 4 cases (20%), the nasopharynx, 2 cases (10%), and the oropharynx, 2 case (10%). There were no differences between the features, at diagnosis or therapeutic modalities for patients with T/NK cell lymphoma and non-T/NK cell lymphoma. The complete remission rate of T/NK cell lymphomas was lower than non-T/NK cell lymphomas (65% vs 85%, p=0.02). The overall survival of T/NK cell lymphomas was 13 months (1-74 month), which was significantly lower than non-T/NK cell lymphomas [60.6% with a median follow up of 22 months (1-101 month, p=0.02)]. Disease free survival of T/NK cell lymphomas was 22 months (4-66 month), significantly lower than non-T/NK cell lymphomas [73.8% with a median follow up of 22 months (2-95 month), p=0.04]. The overall survival rates for T/NK cell lymphomas were significantly lower than for EBV positive non-T/NK cell lymphomas (p=0.018). EBER RNA was detected in the paraffin-embedded tissue sections of all T/NK cell lymphomas, compared to only 17.6% (6 of 34 cases) for non- T/NK cell lymphomas. In conclusion, as patients with T/NK cell lymphomas showed poor clinical outcomes, and a high association with EBV positivity, clinical trials with more investigational therapeutic strategies, and further research into the relationship of EBV infection with pathogenesis of T/NK cell lymphoma is warranted.     

细胞毒颗粒相关蛋白TIA-1在鼻NK/T细胞淋巴瘤及淋巴增生组织中的表达

目的 观察２７例鼻ＮＫ／Ｔ细胞淋巴瘤之瘤细胞表达细胞毒颗粒相关蛋白ＴＩＡ－１的情况及其与该肿瘤的免疫表型,基因型及ＥＢ病毒感染的关系。方法 采用ＳＰ法免疫组织化学染色,选用的抗体有：ＴＬＡ－１,ＣＤ５６,ＣＤ３ε,ＣＤ４５ＲＯ,ＣＤ８和ＣＤ２０等;聚合酶链反应,作ＴＣＲγ链及免疫球蛋白ＪＨ链基因重排,ＥＢＥＲ１／２原位杂交及与ＴＬＡ－１和ＣＤ８等的双标记染色,还与１０例鼻咽淋巴增生病例进行了比较。     

Nasal CD56 positive small round cell tumors

CD56-positive nasal and nasal-type natural killer (NK)/T-cell lymphoma is now a well-defined disease entity. Rare cases of blastic NK-cell lymphoma positive for CD56 have been recently reported. However, CD56 expression is also identified in several types of non-hematopoietic small round cell tumors in which lymphoma is included as a differential consideration. Here, we present nine cases of CD56+ small round cell tumors of histological origin unrelated to nasal NK/T-cell lymphoma. Eight of the nine cases presented as solid tumors of the sinonasal region. Clinical, histological, ultrastructural, and immunohistochemical examination and gene analysis for T-cell receptor (TcR) and immunoglobulin heavy chain (IgH) genes and in situ hybridization (ISH) for Epstein-Barr virus (EBV) were performed. Two cases presented with features consistent with blastic NK-cell lymphoma or lymphoblastic lymphoma of NK-cell phenotype. These cases showed features of lymphoblastic lymphoma, phenotypes of sCD3-, cCD3+, CD45+, CD56+, TdT+, and human leukocyte antigen (HLA)-DR+, germline of IgH and TcR genes, and EBV negative reactivity. One case had myeloid/NK-precursor acute leukemia/lymphoma with a phenotype of CD13+, CD33+, CD34+, CD56+, and MPO-. Three cases were neurogenic, including one case of olfactory neuroblastoma and two of primitive neuroectodermal tumors (PNET). It was difficult to differentiate CD56+ PNET from blastic NK-cell lymphoma, especially when only paraffin-embedded sections were available. Myogenic markers, such as HHF35, alpha-sarcomeric actin, and desmin, were positive in three cases of rhabdomyosarcomas. Our findings suggest that as CD56 is used more routinely as a marker in immunohistochemical staining, the differential diagnosis of extranodal lymphohematological malignancies and small round cell tumors will become more complicated.     

鼻及咽部非霍奇金淋巴瘤158例临床特点及其与EB病毒感染的关系

目的探讨鼻及咽部原发性非霍奇金淋巴瘤（NHL）的临床特点、免疫表型及其与EB病毒感染的关系。方法对158例鼻及咽部原发性NHL进行了HE和免疫组织化学SP法（CD3、CD20、CD56、CD57）检查,按WHO2001年《造血和淋巴组织肿瘤的病理学和遗传学》标准进行分类;并对其中99例进行了EBER-1原位杂交的检测。结果158例鼻及咽部原发性NHL中,原发于鼻腔84例（53．2％）,扁桃体39例（24．7％）,咽部35例（22．1％）。结外鼻型NK／T细胞淋巴瘤101例（63．9％）、非特异性外周T细胞淋巴瘤23例（14．6％）,B细胞淋巴瘤34例（21．5％）。99例EBER-1原位杂交结果显示阳性率：结外鼻型NK／T细胞淋巴瘤为98．6％（70／71）,而非特异性外周T细胞淋巴瘤为66．7％（8／12）,B细胞淋巴瘤为43．8％（7／16）。结论鼻及咽部NHL中结外鼻型NK／T细胞淋巴瘤最为多见,与EB病毒密切相关,其病理诊断需结合其免疫表型特征及肿瘤部位。     

Nodal T/NK-cell lymphoma of nasal type: a clinicopathological study of six cases

Aims:  To investigate the clinicopathological features of six unusual cases of nodal CD56+ and Epstein–Barr virus (EBV)+ T/natural killer (NK)-cell lymphoma, a putative nodal counterpart of nasal NK/T-cell lymphoma (nodal T/NK-cell lymphoma of nasal type) in comparison with nasal NK/T-cell lymphoma with secondary lymph node involvement ( n  = 24) and peripheral T-cell lymphoma (PTCL) of cytotoxic molecule (CTM)+ and EBV+ type ( n  = 21).
Methods and results:  All cases of nodal T/NK-cell lymphoma of nasal type exhibited diffuse infiltration of pleomorphic medium-sized to large tumour cells, reminiscent of those in CTM+ EBV+ PTCL. The tumour cells had a typical phenotype of nasal NK/T-cell lymphoma: CD2+, CD3ε+, CD4−, CD5−, CD56+, T-cell intracellular antigen-1+, granzyme B+, perforin+ and EBV+. However, four of six cases demonstrated clonal T-cell receptor γ-gene rearrangement on polymerase chain reaction analysis, unlike nasal NK/T-cell lymphoma. Comparison of clinical parameters and overall survival among the three groups demonstrated only minor differences.
Conclusions:  Nodal T/NK-cell lymphoma may occupy the grey zone between extranodal nasal-type NK/T-cell lymphoma and nodal CTM+ PTCL in a spectrum of NK to T-cell lymphomas that are EBV+. The close relationship between NK/T-cell lymphomas and cytotoxic T-cell lymphomas was also substantiated.     

应用组织芯片技术探讨"恶性组织细胞增生症"肿瘤细胞属性及其与EB病毒感染的关系

目的：初步探讨所谓“恶性组织细胞增生症”（简称恶组）肿瘤细胞的属性及其与EB病毒感染之间的关系。方法：用组织芯片技术将5例“恶组”尸检病例的每例不同组织各集成在一张组织芯片上,用免疫组织化学标记链霉素卵白素生物素（LSAB）法检测瘤细胞的免疫表型,用EBER1／2原位杂交检测Epstein-Barr(EB)病毒感染的情况。结果：（1）5例瘤细胞均表达CD45RO、CD3ε、T细胞限制性细胞内抗原－1（TIA－1）、Granzyme B,无瘤细胞表达CD56、CD30、CD20、CD68。（2）5例EBER1／2原位杂交均为阳性（簇型3例、弥漫型2例）。结论：至少部分“恶组”为EB病毒相关的侵袭性T细胞淋巴瘤。     

EBV‐encoded RNA1‐positive cells in the bone marrow specimens of patients with EBV‐negative lymphomas and sarcomas

Epstein‐Barr virus (EBV) infection is associated with pathogenesis of various cancers, including extranodal natural killer/T‐cell lymphoma, nasal type (ENKL). ENKL tumor cells are positive for EBV‐encoded RNA1 (EBER1), which is the most useful marker to identify ENKL tumor cells in histopathology. Currently, EBER1 in situ hybridization (ISH) is recommended to evaluate bone marrow (BM) involvement of ENKL. However, the actual burden of EBER1‐positive cells in normal BM specimens remains unclear. In the present study, we performed EBER1 ISH on 111 BM specimens, which were obtained during an initial staging procedure in patients with EBV‐negative cancers and were also negative for BM involvement. One or more EBER1‐positive cells per whole specimen were observed in 38 specimens (34%). The number of EBER1‐positive cells was distributed as follows: single positive cell, n = 17; two positive cells, n = 13; three positive cells, n = 3; and four positive cells, n = 5. These findings suggest that four or fewer EBER1‐positive cells can be observed in BM specimens of patients with non‐EBV‐related cancers. The clinical implications of a small number of EBER1‐positive cells in BM specimens of patients with ENKL should be evaluated in further studies.     

Three cases of extranodal NK/T-cell lymphoma of the nasal type diagnosed by nasal brush cytology

Extranodal natural killer (NK)/T-cell lymphoma of the nasal type is a rare type of malignant lymphoma that is most common in Asian countries. Here we describe cytomorphologic, immunocytochemical, and molecular cytochemical features of three cases of NK/T-cell lymphoma of the nasal type diagnosed by nasal brush cytology. Cytomorphologic findings common among the three cases included the presence of several cell types, including nasal cavity epithelial cells, histiocytes, phagocytic histiocytes, and lymphoid cells, within a necrotic background. Suspected lymphoma cells were medium to large lymphoid cells possessing light blue and abundant cytoplasm. A characteristic feature of these cells was the presence of the tongue-like projections of cytoplasm from one or both sides of the cells. We believe these intriguing cytologic findings are indicators of NK/T-cell lymphoma of the nasal type. Azurophilic granules were observed in all cases, ranging from extremely fine granules to large granular lymphocyte (LGL)-like granules. Immunocytochemical and molecular cytochemical analyses showed staining for natural killer cell antigen CD56 as well as cytotoxic granule-associated proteins granzyme B7 (GrB7) and T-cell-restricted intercellular antigen-1 (TIA-1). EBV (Epstein-Barr virus) encoded small RNAs (EBER) positivity was shown by in situ hybridization, and no rearrangement of the TCRgamma gene was observed. Comparison between cytobrush and cotton swab methodology showed that cytobrush resulted in more cell-rich specimens than did cotton swabs, suggesting that nasal brush cytology with cytobrush is most useful in the diagnosis of NK/T-cell lymphoma of the nasal type.     

Cases of cutaneous and nasal CD56 (NCAM)-positive lymphoma in Japan have differences in immunohistology, genotype, and etiology.

CD56 (NCAM)-positive lymphoma frequently involves the skin and nasal area. This study shows it is likely that the clinicopathologic features of this lymphoma are distinctive to each of the primarily involved sites. Sixteen cutaneous and 11 nasal cases of CD56-positive lymphoma were examined. In 10 cutaneous cases, the lesions consisted of pleomorphic large-cell lymphoma that expressed CD3epsilon (CD3), CD2 (LFA2), CD4, CD122 (IL-2B receptor), TIA1, perforin, and granzyme B and displayed angiocentric/angiodestructive features. Lobular panniculitis was found in 8 of these cases, and 6 cases showed other organ involvement. The remaining 6 cutaneous cases consisted mostly of CD3epsilon- and CD4-positive, CD2-, CD122-, and TIA1-negative large blastic lymphoma, having less angiodestruction and panniculitis. Bone marrow invasion and leukemic changes were found in 4 of these cases during the clinical course. All 11 nasal cases showed pleomorphic small and medium-size lymphoma cells with angiodestructive features and were positive for CD3epsilon, CD2, CD122, TIA1, perforin, and granzyme B. CD4-positive lymphoma was found in 4 of these cases. Only 3 nasal cases showed other organ involvement. Genotypically, 2 of the 4 cases examined in the first cutaneous group, 3 of the 4 cases examined in the second cutaneous group, and only 1 of the 11 nasal cases showed rearrangement of the TcRCbeta gene by the Southern blot method. Only 2 cutaneous cases with panniculitis and all 11 nasal cases showed a positive nuclear signal for EBV-encoded RNA (EBERs) by in situ hybridization. Thus, two types of cutaneous CD56-positive lymphoma were found, each having a unique cell characteristic, genotype, and EBV infection pattern that differed from that of nasal-type lymphoma.     

First reported cases of intravascular large cell lymphoma of the NK cell type: clinical, histologic, immunophenotypic, and molecular features

Most cases of intravascular large cell lymphoma are of B-cell phenotype, with a few cases of T-cell lineage and rare cases with histiocytic features described. A definitive natural killer (NK) cell variant has not been recognized. This report is the first to describe the clinical, histologic, immunophenotypic, and molecular features of 2 cases of intravascular lymphoma with an NK cell phenotype (CD3epsilon+, CD2+, CD7+, CD56+, T-cell intracytoplasmic antigen-1+, perforin+, granzyme B+, CD20-, CD4-, CD5-, CD8-, T-cell receptor [TCR]betaF1-). Molecular studies for TCR gene rearrangements revealed a germline configuration. A 41-year-old man had erythematous plaque-like subcutaneous lesions of the lower extremities in which biopsy revealed Epstein-Barr virus-positive intravascular lymphoma. Following chemotherapy and stem cell transplantation, he was alive with no evidence of disease at 1 year. A 47-year-old woman had myalgias, arthralgias, weakness, fever, altered mental status, and pancytopenia. Bone marrow biopsy demonstrated intravascular lymphoma. Therapy was initiated; however, her condition deteriorated rapidly, and she died. Autopsy revealed involvement of multiple organs, including brain, kidneys, ovaries, and bone marrow. These cases represent the first documented examples of an NK cell variant of intravascular lymphoma.     

CD4+CD56+ lineage negative hematopoietic neoplasm: so called blastic NK cell lymphoma

Blastic natural killer (NK) cell lymphoma is a rare neoplasm characterized by blastoid tumor cells expressing CD4 and CD56, with predominant skin involvement. Although this tumor has been regarded as a neoplasm related to NK cell, recent studies suggested that it is derived from plasmacytoid dendritic cells, but not from NK cell. Herein we report 4 cases of CD4+CD56+ lineage marker-blastic NK cell lymphomas with a review of literatures. The patients were 3 men and one woman. Three of them were young (17, 18, and 22 yr old). Three patients had skin lesions, at initial presentation in two patients and during the course of disease in other patient. Histologically, tumors consisted of monotonous medium to large blastoid cells showing no necrosis, angiocentric growth or epidermotrophism. All four tumors were CD4+ and CD56+. Three expressed CD68 antigen. Lineage specific markers for B- and T cell were negative. All tumors did not express myeloperoxidase. T-cell receptor gene rearrangement, EBV, CD13 and CD33 were negative. In one patient, tumor cells arranged in Homer-Wright type pseudorosette and expressed terminal deoxynucleotidyl transferase(TdT). Despite the standard lymphoma chemotherapy, the tumors, except one lost during follow-up, progressed and relapsed. The patients died 8-60 months after diagnosis.     

Diagnostic cues for natural killer cell lymphoma: primary nodal presentation and the role of in situ hybridisation for Epstein-Barr virus encoded early small RNA in detecting occult bone marrow involvement

Natural killer (NK) cell lymphomas are rare, and atypical features might lead to diagnostic pitfalls. This report describes an unusual patient in whom lymphoma occurred initially as isolated lymph node involvement, an exceptional presentation of an almost exclusively extranodal disease. Furthermore, during the terminal haemophagocytosis in the bone marrow, lymphoma cells lost the expression of the NK cell marker, CD56, making the histopathological diagnosis of bone marrow involvement difficult. This was resolved by in situ hybridisation for Epstein-Barr virus encoded small RNA, which detected occult bone marrow infiltration.     

Expression of cyclin-dependent kinase 6 (cdk6) and frequent loss of CD44 in nasal-nasopharyngeal NK/T-cell lymphomas: comparison with CD56-negative peripheral T-cell lymphomas

Lymphomas involving the nasal and nasopharyngeal region mainly include CD56-positive natural killer (NK)/T-cell lymphomas, CD56-negative peripheral T-cell lymphomas (PTL), and B-cell lymphomas. Among these, the CD56-positive lymphoma, presumably of an NK/T-cell nature, is frequently seen in Asian, Mexican, and South American patients. NK cells are proposed to be closer developmentally to T cells than to other lymphoid cells, because bipotential common progenitor cells of NK/T-cell lineage have been isolated. In this study, we collected 47 cases of nasal lymphoma and investigated the phenotypic difference between NK/T-cell lymphoma and PTL by examining the pattern of the developmentally differentially expressed molecules cdk6 (cyclin-dependent kinase 6), CD44, CD117, and by examining the rearrangement of the T-cell receptor gene (TcR-GR). cdk6, an essential regulator of the cell cycle in G1 progression, was over-expressed in a subset of cortical thymocytes, but absent in mature thymocytes. In contrast, CD44, a glycosylated adhesion molecule, was absent in cortical thymocytes, but present in mature thymocytes and peripheral activated T cells. We found both over-expression of nuclear cdk6 (n-cdk6) and frequent absence of CD44 in nasal CD56-positive NK/T-cell lymphomas, in contrast to most nasal CD56-negative PTL, which were CD44-immunoreactive with weak or no expression of n-cdk6. Almost all tested cases of NK/T-cell lymphoma displayed a germ-line configuration of TcR, without evidence of gene rearrangement. Thus, there seems to be a useful distinction between the classical NK/T type of nasal lymphoma (CD56+/n-cdk6+/CD44-/TcR-GR-) and PTL (CD56-/n-cdk6-/CD44+/TcR-GR+) involving the nasal region. The presence of Epstein-Barr virus does not seem to be a good marker for distinguishing between NK/T lymphoma and PTL involving the nasal region.     

CD56+/CD4+ lymphomas and leukemias are morphologically, immunophenotypically, cytogenetically, and clinically diverse

CD56, a neural adhesion molecule, is a marker of natural killer (NK) lymphocytes as well as a subgroup of CD8+ T cells. Normal lymphocytes with a CD56/CD4 phenotype are scarce. Physiologic increases may occur in patients with immunosuppression, chronic inflammation, and autoimmune disorders. We report 4 cases of lymphomas/leukemias with the unusual CD56/CD4 phenotype. Two were of T-cell and 2 of true NK-cell origin. The T-cell lymphomas had large granular lymphocyte morphologic features and splenomegaly. One patients had a benign course; the other died within months of the leukemia diagnosis. The 2 NK cell lymphomas had blastic morphologic features, initially involved skin, and had a very aggressive clinical course; 1 patient died of acute leukemia, and 1 had recurrence after bone marrow transplantation. Cytogenetic analyses did not show a consistent pattern of abnormalities. The NK lymphoma with acute leukemia had a t(2;5) but was CD30- and anaplastic lymphoma kinase negative. Although CD56+/CD4+ lymphomas/leukemias are a heterogeneous group, there may be a distinct subgroup of NK lymphoblastoid lymphomas of the skin, judging from our cases, as well as those previously reported.     

淋巴结细胞毒性自然杀伤/T细胞淋巴瘤

目的 探讨淋巴结细胞毒性自然杀伤（NK/T）细胞淋巴瘤的临床病理学特征。方法 对5例淋巴结细胞毒性NK/T细胞淋巴瘤作临床病理观察及随访、用ISAB法做免疫表型分析（CD35RO、CD8、CD56、CD30、CD20、TIA-1）及EBER1/2原位杂交检测。结果 淋巴结细胞毒性NK/T细胞淋巴瘤的瘤 理组织学特点为：（1）淋巴结结构明显破坏并被瘤细胞所取代：（2）瘤细胞呈多形性;（3）我数肿瘤细胞表达淋巴细胞分化抗原。5例中CD45RO阳性的有4例,其中3例瘤细胞同时呈CD56阳性;1例为无标记细胞性;所有病例的TIA-1和EBER均为阳性。结论 淋巴结细胞毒性NK/T细胞淋巴瘤有特征性的形态改变和免疫表型。提示肿瘤进展及预后不良。