Expression of natural killer cell markers in non-Hodgkin's lymphomas

Few and far between: clinical management of rare extranodal subtypes of mature T-cell and NK-cell lymphomas

While all peripheral T-cell lymphomas are uncommon, certain subtypes are truly rare, with less than a few hundred cases per year in the USA. There are often no dedicated clinical trials in these rare subtypes, and data are generally limited to case reports and retrospective case series. Therefore, clinical management is often based on this limited literature and extrapolation of data from the more common, nodal T-cell lymphomas in conjunction with personal experience. Nevertheless, thanks to tremendous pre-clinical efforts to understand these rare diseases, an increasing appreciation of the biological changes that underlie these entities is forming. In this review, we attempt to summarize the relevant literature regarding the initial management of certain rare subtypes, specifically subcutaneous panniculitis-like T-cell lymphoma, hepatosplenic T-cell lymphoma, intestinal T-cell lymphomas, and extranodal NK/T-cell lymphoma. While unequivocally established approaches in these diseases do not exist, we make cautious efforts to provide our approaches to clinical management when possible.

An update on viral-induced cutaneous lymphoproliferative disorders. CME Part I

Viral-induced cutaneous T-cell lymphomas are an uncommon group of lymphoproliferative disorders characterized by a viral infection of T and natural killer (NK) cells. This group of cutaneous T-cell lymphomas is more commonly encountered in Asians and Native Americans from Central and South America compared with Western populations. Viral-associated lymphoproliferative disorders include a spectrum of entities that range from nonneoplastic lesions, such as chronic active Epstein-Barr virus infection and infective dermatitis to malignant diseases, such as extranodal NK/T-cell lymphoma, hydroa vacciniforme-like T-cell lymphoma, and adult T-cell leukemia/lymphoma. This review article will focus on hydroa vacciniforme-like lymphoproliferative disorder, extranodal NK/T-cell lymphoma, adult T-cell leukemia/lymphoma, lymphomatoid granulomatosis, and Epstein-Barr virus-positive mucocutaneous ulcers. We will review the pathogenesis of these conditions and the challenges of making a timely diagnosis in early-stage disease and discuss the common clinicopathologic manifestations, mutational landscape, and approaches to treat these highly aggressive and frequently lethal types of lymphoma.

Treatment of extranodal NK/T-cell lymphoma: From past to future

Extranodal NK/T-cell lymphoma (ENKTCL) is the most common subtype of T/NK-cell lymphoma in Asia and Latin America, but very rare in North American and Europe. Patient survival has improved significantly over the past two decades. However, standard treatment has not yet been established, although dozens of prospective trials have been conducted. To help understand how the treatment of ENKTCL has evolved in the past and what trends lie ahead, we have comprehensively reviewed the treatment of this aggressive malignancy, with a particular focus on neglected or unanswered issues, such as the optimal staging method, the best partner of asparaginase (Asp), the individualized administration of Asp, the preferred sequence of CT and RT and so on. Overall, the 5-year overall survival (OS) of patients with Ann Arbor stage I/II disease increased from < 50% in the early 20th century to > 80% in recent years, and the median OS of patients with Ann Arbor stage III/IV disease increased from < 1 year to more than 3 years. The improvement in patient survival is largely attributable to advances in radiation technology and the introduction of Asp and anti-PD-1/PD-L1 immunotherapy into practice. Radiotherapy is essential for patients with early-stage disease, while Asp-based chemotherapy (CT) and PD-1/PD-L1 inhibitors significantly improved the prognosis of patients with advanced-stage disease. ENKTCL management is trending toward simpler regimens, less toxicity, and higher efficacy. Novel drugs, such as manufactured T cells, monoclonal antibodies, and small molecule inhibitors, are being intensively investigated. Based on the fact that ENKTCL is highly resistant to cytotoxic drugs except Asp, and aggressive CT leads to higher toxicity rather than better outcomes, we recommend it is unnecessary to expend additional resources to compare different combinations of Asp with cytotoxic agents. Instead, more efforts should be made to optimize the use of Asp and immunotherapy to maximize efficacy and minimize toxicity, explore ways to overcome resistance to Asp and immunotherapy, identify novel treatment targets, and define subpopulations who may benefit more from specific treatments.

Extranodal NK/T-Cell Lymphoma, Nasal Type: Genetic, Biologic, and Clinical Aspects with a Central Focus on Epstein-Barr Virus Relation

Extranodal NK/T-Cell Lymphoma, nasal type (ENKTL-NT) has some salient aspects. The lymphoma is commonly seen in Eastern Asia, has progressive necrotic lesions in the nasal cavity, makes midfacial destructive lesions, and shows poor prognosis. The lymphoma cell is originated from either NK- or γδ T-cells, which express CD56. Since the authors first demonstrated the existence of Epstein–Barr virus (EBV) DNA and EBV oncogenic proteins in lymphoma cells, ENKTL-NT has been recognized as an EBV-associated malignancy. Because the angiocentric and polymorphous lymphoma cells are mixed with inflammatory cells on a necrotic background, the diagnosis of ENKTL-NT requires CD56 immunostaining and EBER in situ hybridization. In addition, serum the EBV DNA level is useful for the diagnosis and monitoring of ENKTL-NT. Although ENKTL-NT is refractory lymphoma, the prognosis is improved by the development of therapies such as concomitant chemoradiotherapy. The basic research reveals that a wide variety of intracellular/cell surface molecules, cytokines, chemokines, and micro RNAs are involved in lymphomagenesis, and some of them are related to EBV. Understanding lymphoma behavior introduces new therapeutic strategies, such as the usage of immune checkpoint inhibitors, peptide vaccines, and molecular targeting therapy. This review addresses recent advances in basic and clinical aspects of ENKTL-NT, especially its relation to EBV features.

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

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

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.

Nasal NK/T Cell Lymphoma Presenting with Perforation of Palate: A Case Report and Review of Literature

Nasal Natural Killer (NK)/T cell lymphoma, commonly mentioned in the literature as Lethal Midline Granuloma (LMG) is an unusual pathology of the oro-maxillo-facial region characterized by aggressive and progressive destruction of the face, nose, palate and pharynx. This disease is now classified as a T-cell lymphoma based on modern cytogenetics, immunologic and molecular studies. However, it is mentioned in various literatures by various names. Here, we present one such clinically diagnosed, histopathologically and immunologically confirmed case of LMG, designated as NK/T cell lymphoma in a 56-year-old male. The uncommon presentation of NK/T cell lymphomas should be kept as a differential diagnosis for management of patients.

Novel targets for natural killer/T-cell lymphoma immunotherapy

Extranodal natural killer/T-cell lymphoma, nasal type (NKTL) is a rare but highly aggressive Epstein-Barr virus-related malignancy, which mainly occurs in nasopharyngeal and nasal/paranasal areas. In addition to its high prevalence in Asian, Central American and South American populations, its incidence rate has been gradually increasing in Western countries. The current mainstay of treatment is a combination of multiple chemotherapies and irradiation. Although chemoradiotherapy can cure NKTL, it often causes severe and fatal adverse events. Because a growing body of evidence suggests that immunotherapy is effective against hematological malignancies, this treatment could provide an alternative to chemoradiotherapy for treatment of NKTL. In this review, we focus on how recent findings could be used to develop efficient immunotherapies against NKTL.

Extranodal NK/T-cell lymphoma, nasal type (angiocentric T-cell lymphoma): A review about the terminology

Extranodal NK/T-cell lymphoma, nasal type (ENKL) is a rare lymphoid neoplasm, which in the past has been grouped with a variety of granulomatous diseases. It is an aggressive non-Hodgkin’s type characterized clinically by aggressive, nonrelenting destruction of the midline structures of the palate and nasal fossa. Despite the malignant clinical course, histological diagnosis can be difficult because of extensive tissue necrosis and multiple biopsies that are often required and has an ominous prognosis, as the average survival rate is between 6 and 25 months as reported with a large number of Asian studies. Several American and European studies have shown similar results. This is the case report of a 60-year-old male patient who presented with nasal obstruction and foul smelling, ulcerative lesion over the palate of 6 months duration, which had been treated with antibiotics and anti-inflammatories without success. After performing a number of diagnostic tests, it was found histologically and confirmed by immunohistochemical analysis that the patient had an ENKL, nasal type (also known as angiocentric T-cell lymphoma).

Extranodal NK/T-cell lymphoma: diagnosis and treatment cues

Extranodal NK/T-cell lymphoma, nasal type (ENKL) is mostly endemic to East Asia. It predominantly occurs in the nasal or paranasal areas and less frequently in the skin. Most of the tumours show NK-cell, but rarely T-cell, phenotypes. The Epstein-Barr virus (EBV) genome can be usually detected in lymphoma cells. Geographic localization of ENKL matches the endemic distribution of EBV, suggesting that EBV plays an important role in lymphomagenesis. Originally, NK-cell and T-cell types were believed to present the same clinicopathologic characteristics, but recent data suggest more aggressive characteristics for the NK-cell phenotype. Although ENKL is sensitive to radiotherapy, it shows a poorer response to chemotherapeutic agents than other lymphomas due to expression of p-glycoprotein. Therefore, new therapeutic approaches must be considered. Several new clinical trials are now being conducted in East Asia.

Nasal NK/T-cell lymphoma: epidemiology and pathogenesis

Nasal NK/T-cell lymphoma (NKTCL) is an uncommon disease, but usually shows a highly aggressive clinical course. The disease is much more frequent in Asian and Latin American countries than in Western countries, and is universally associated with Epstein–Barr virus (EBV) infection. Analyses of gene mutations, especially p53 and c-KIT, revealed the different frequencies by district. Epidemiological studies revealed the changes of the disease frequency in Korea during the period from 1977–1989 to 1990–1996. Case-control study showed that the exposure to pesticides and chemical solvents could be causative of NKTCL. Further studies including HLA antigen typing of patients is necessary to further clarify the disease mechanism.

Combined chemotherapy and external beam radiation for stage IE and IIE natural killer T-cell lymphoma of nasal cavity

To evaluate the outcome of CHOP chemotherapy and radiotherapy in Stage IE and IIE nasal natural killer (NK)/T-cell lymphoma, 53 patients with stage IE and IIE nasal NK/T-cell lymphoma were studied. By the Ann Arbor Lymphoma Staging Classification, 41 patients (77%) had Stage IE disease and 12 patients (23%) had Stage IIE disease. All patients were treated curatively using chemotherapy, followed by radiotherapy. Chemotherapy consisted of up to six cycles of the standard CHOP based regimen. The median radiation dose to the tumor bed was 45 Gy for all patients. The median follow-up for all 39 surviving patients was 30.2 months (range, 6 - 104 months). Twenty-six patients had complete response after chemotherapy, and all patients who completed first line chemotherapy achieved complete response after radiotherapy. The 2-year overall survival and progression-free survival rates were 75.6% and 61.8%, respectively. Multivariate analysis revealed that perforation as a presenting symptom, elevated pretreatment serum lactate dehydrogenase level, and ECOG performance status >or=2 were significant independent prognostic factors for this group of patients. Combined chemotherapy followed by involved field radiation produced suboptimal outcome for patients with early stage nasal NK/T-cell lymphoma. Further investigations, preferably prospective clinical trials, for more efficacious treatment strategies are needed to improve the treatment outcome of this malignancy.

Combined chemoradiation for the management of nasal natural killer (NK)/T-cell lymphoma: elucidating the significance of systemic chemotherapy

The objective of this analysis was to evaluate the efficacy and treatment outcome of CHOP and CHOP combined with nitrosourea chemotherapy in natural killer (NK)/T-cell lymphoma of the nasal cavity. Sixty-three patients with NK/T-cell lymphoma of the nasal cavity were treated with CHOP or CHOP combined with oral nitrosourea chemotherapy between January 1997 and June 2005. By the Ann Arbor Lymphoma Staging Classification, 57 patients (90%) had Stage IE or IIE disease and six patients (10%) had Stage III or IV disease. All patients with Stage IE or IIE disease were intended to be treated curatively with combined chemoradiation; and patients who had Stage III or IV disease were treated with chemotherapy alone with curative intention. Chemotherapy consisted of: (1) up to six cycles of the standard CHOP based regimen, or (2) up to six cycles of the standard CHOP based regimen with oral Semustine dosed at 120 mg (or Lomustine dosed at 100mg) on day 1 of each chemotherapy cycle. External beam radiation therapy was delivered by daily conventional fractionation by Co-60 or 6MVx linear accelerator for patients with Stage IE or IIE disease. The radiation dose to the tumor bed was between 36 and 50 Gy with a median dose of 45 Gy. Fifty-three patients received chemotherapy prior to radiation, and four patients were treated with involved field radiation before chemotherapy. The median follow up for all 44 surviving patients was 31 months (range: 6-104 months). The 2-year progression-free survival (PFS) and overall survival (OS) rates were 60% and 70%, respectively. The PFS and OS of patients who were treated with or without oral nitrosourea in addition to CHOP were 73% vs. 44% (P=0.035) and 75% vs. 64% (P=0.276), respectively. Nine patients with Stage IE or IIE diseases developed disease progression during their planned treatment and died within 10 months after the initiation of treatment; Six patients who achieved complete response (CR) after planned chemoradiation developed systemic recurrence and died at 13-48 months despite salvage treatment; one patient died of Hemophagocytic Syndrome during radiotherapy after achieving CR from chemotherapy. Three patients with Stage III or IV disease died during chemotherapy or during salvage treatment at 2, 4, and 19 months, respectively. Among the 59 patients who received chemotherapy as their initial treatment, 29, 6, 12, and 12 patients had complete response (CR), partial response (PR), stable disease (SD), and progressive disease (PD) respectively after chemotherapy. The 2-year overall survival rates for these four groups of patients were 100%, 75%, 60%, and 17%, respectively (P<0.0001). Multivariate analysis revealed that International Prognostic Index (IPI) for Lymphoma, perforation of nasal septum as a presenting symptom, "B" symptoms, ECOG performance, as well as response after chemotherapy, were significant independent prognostic factors for this group of patients. The extent of response after induction chemotherapy is significantly related to the treatment outcome of patients with nasal NK/T-cell lymphoma. CHOP based chemotherapy combined with oral nitrosourea followed by involved field radiotherapy may provide improved treatment results compared to conventional CHOP chemotherapy and radiation. This strategy needs to be optimized and tested in a prospective trial for its efficacy.

CD56-Positive Large B-cell Lymphoma

CD56 (NCAM), a neural adhesion molecule, is normally expressed on natural killer cells and subsets of T cells and is commonly seen on hematolymphoid neoplasms such as plasma cell myeloma and acute myelogenous leukemia. It is uncommon in B-cell lymphoma. From 2001 to 2003 a cohort of 20 cases of CD56 B-cell lymphomas was identified by flow cytometry (<0.5% of all B-cell lymphomas studied) during a 2-year period. Most (90%) expressed CD10 and 5/5 tested cases were BCL6, suggesting a follicular origin. An extranodal disease presentation was seen in 45% and may be related to CD56 expression. These CD56 B-cell lymphomas may represent a new subset of large B-cell lymphoma. The relationship of cells with this antigenic profile to normal B-cell differentiation is explored.

Clinical analysis of extranodal non-Hodgkin's lymphoma in the sinonasal tract

We investigated the clinical analysis of non-Hodgkin's lymphoma (NHL) of the sinonasal tract, including the survival rate and treatment outcome. Fifty patients who had previously received a diagnosis of extranodal NHL of the sinonasal cavity from May 1992 to April 2001 were included. We reviewed the patients' clinical characteristics and the survival rates, retrospectively. Of 50 patients, 49 were classified as having extranodal NK/T cell lymphoma and only one patient as having diffuse large B cell (DLBC) lymphoma according to the new WHO classification. Even though higher mortality rates were observed in patients receiving chemotherapy alone than in those receiving chemotherapy and radiation therapy in the advanced stage, the combination treatment of chemotherapy and radiation therapy failed to demonstrate a significantly higher survival rate.

Genomic alterations in blastic natural killer/extranodal natural killer-like T cell lymphoma with cutaneous involvement

Natural killer and natural killer-like T cell lymphomas represent a rare type of non-Hodgkin's lymphoma originally described to involve the upper aerodigestive tract. This malignancy has been increasingly observed in other extranodal sites, particularly in the skin. Patients with cutaneous natural killer cell lymphoma generally have a poor prognosis; however, the etiology and the underlying molecular pathogenesis remain unclear. This study aimed to investigate comprehensively genomic changes in blastic natural killer and extranodal natural killer-like T cell lymphoma with cutaneous involvement. Comparative genomic hybridization showed chromosome imbalances in six of eight cases studied (75%). The mean number of chromosome imbalances per sample was 2.18+/-1.63 with similar number of gains (1.18+/-1.17) and losses (1.00+/-1.34). The most frequent DNA copy number changes observed were losses of 9/9p (83%), followed by loss of 13q and gain of 7 (67%). Similar patterns of chromosome imbalances were observed in both blastic natural killer and cutaneous natural killer-like T cell lymphomas. Loss of the RB1 gene at 13q14.2 was detected in one blastic natural killer cell lymphoma with 13q loss using a gene dosage assay, and in one cutaneous natural killer-like T cell lymphoma without 13q loss using fluorescent in situ hybridization. Genomic microarray analysis identified oncogene copy number gains of PAK1 and JUNB in three of four cases studied, and gains of RAF1, CTSB, FGFR1, and BCR in two cases. Real-time polymerase chain reaction detected amplification of CTSB and RAF1 in four of five cases analyzed, JUNB and MYCN in three cases, and REL and YES1 in two cases, respectively. In conjunction with this study, an extensive literature search for the published G-banded karyotypes of four subsets of natural killer cell lymphomas was conducted, which showed a nonrandom pattern of multiple chromosome aberrations. These results reveal consistent genetic alterations in cutaneous natural killer cell lymphomas, and provide a basis for further investigation of molecular pathogenesis in this malignancy.

Natural killer cell neoplasms: a distinctive group of highly aggressive lymphomas/leukemias

Natural killer (NK) cell neoplasms, which include extranodal NK/T-cell lymphoma (nasal and extranasal) and aggressive NK cell leukemia, are generally rare, but they are more common in people of Oriental, Mexican and South American descent. These neoplasms are highly aggressive, and show a strong association with Epstein-Barr virus. Extranodal NK/T-cell lymphoma most commonly affects the nasal cavity and other mucosal sites of the upper aerodigestive tract. Patients present with nasal obstruction or midfacial destruction. Despite the early stage of disease at presentation, overall survival is poor. Patients with the extranasal form of the lymphoma often present with high-stage disease, commonly involving the skin, gastrointestinal tract, testis, and soft tissue, and the prognosis is even worse. Histologically, the lymphoma can show a broad cytologic spectrum, but apoptosis, necrosis, and angioinvasion are common. The most common immunophenotype is CD2(+), surface CD3(-), cytoplasmic CD3(+), CD56(+). Based on currently available data, treatment of nasal NK/T-cell lymphoma should consist of radiotherapy, with or without multiagent chemotherapy. More research is required to ascertain the role of high-dose chemotherapy with stem cell rescue and that of non-multidrug resistance-related chemotherapeutic agents. Aggressive NK cell leukemia affects younger patients, who present with poor general condition, fever, and disseminated disease; they often die within a short time from systemic disease or complications such as multi-organ failure. The peripheral blood and bone marrow show atypical large granular lymphocytes, which exhibit an immunophenotype similar to that of extranodal NK/T-cell lymphoma. Aggressive NK cell leukemia must be distinguished from T-cell large granular lymphocyte leukemia and indolent NK cell lymphoproliferative disorder, both of which are indolent.

Early stage nasal NK/T-cell lymphoma: clinical outcome, prognostic factors, and the effect of treatment modality

PURPOSE

To determine the clinical outcome, prognostic factors, and effect of adding combination chemotherapy to radiation therapy on disease control and survival in early stage nasal natural killer (NK)/T-cell lymphoma.

METHODS AND MATERIALS

A retrospective "intent to treat" analysis was carried out on 79 patients treated consecutively with curative intent between 1977 and June 2001. They all had early stage (Ann Arbor Stage I(E): 63, II(E):16) nasal NK/T-cell lymphoma. Sixty-one were planned for combined modality treatment (CMT); radiotherapy alone (RT) was intended for 18. Three to 6 cycles of anthracycline-containing regimens were aimed at for patients intended for CMT. Patients selected for RT were generally older or treated during the earlier part of the study period.

RESULTS

The overall complete response (CR) rate was 68.4% (54/79), of whom 44.4% (24/54) relapsed after 54.9 months median follow-up of the survivors. The 5-year disease-free survival (DFS) and overall survival (OS) rates were 35.5% and 37.9%, respectively. On multivariate analysis, good performance status (Eastern Cooperative Oncology Group [ECOG] <2) was shown to be a significant favorable factor for DFS (p = 0.011), whereas good performance status (ECOG <2) and Ann Arbor Stage I(E) disease were shown to be significant favorable factors for OS (p = 0.001 and p = 0.013, respectively). The type of intended treatment was not a significant factor for DFS (5-year DFS CMT vs. RT = 35.8% vs. 30.5%, p = 0.795) or OS (5-year OS CMT vs. RT = 40.3% vs. 29.8%, p = 0.693) though only 2 of the 16 Stage II(E) patients were intended for RT alone. Resistance to treatment, especially to chemotherapy, was common. Of 61 patients intended to be given CMT, 31 showed disease progression while receiving chemotherapy, of whom 17 progressed locoregionally. Nine of the latter group were rendered CR by salvage radiotherapy.

CONCLUSIONS

The overall outcome in early stage nasal NK/T-cell lymphoma is poor. Performance status and Ann Arbor stage are significant factors influencing DFS and OS. The addition of anthracycline-containing chemotherapy to radiotherapy does not appear to confer any survival benefit in Stage I(E) patients. Therefore, radiation therapy remains the mainstay of treatment for this lymphoma type.

A case of NK/T-cell lymphoma complicated by a squamous cell carcinoma of hard palate during combination chemotherapy and radiation therapy

NK/T-cell lymphoma, which often shows an angiocentric growth pattern, is a distinct clinicopathologic entity highly associated with Epstein-Barr virus. The disease is characterized by a destruction of the upper respiratory tract, particularly the nasal cavity, palate and paranasal sinuses. Interestingly, NK/T-cell lymphoma is closely linked to a variety of complications, such as hemophagocytic syndrome, second primary cancer, sepsis and bleeding. Here we report a case of a 50-year-old man diagnosed initially as NK/T-cell lymphoma of the oropharynx and who developed a second primary carcinoma of the hard palate during combination chemotherapy and radiation therapy.

p53 Mutations in nasal natural killer/T-cell lymphoma from Mexico: association with large cell morphology and advanced disease

Nasal NK/T-cell lymphoma is a unique form of lymphoma highly associated with Epstein-Barr virus, and with a characteristic geographic distribution. Recently, we showed that p53 is overexpressed in a high percentage of nasal NK/T-cell lymphomas. The aim of this study was to analyze the status of the p53 gene, and correlate it with the expression of p53 protein and its downstream target, the cyclin-dependent kinase inhibitor p21, in a series of 25 cases of well-characterized nasal NK/T-cell lymphoma from Mexico. The highly conserved exons 5 to 8 of the p53 gene were amplified by polymerase chain reaction and screened for mutations by denaturing high-pressure liquid chromatography. Abnormal polymerase chain reaction products detected by denaturing high-pressure liquid chromatography and additional selected cases were sequenced. In addition, the incidence of loss of heterozygosity at the p53 locus was analyzed in 12 cases. Of the 25 patients, 17 were male and 8 female (M:F ratio, 2.1:1), with a median age of 43 years (range, 21 to 93 years). Morphologically, most of the cases were composed of a mixture of medium-sized cells and large transformed cells (21 cases), and four cases were composed exclusively of large transformed cells. Three different groups determined by p53 gene status and expression of p53 protein were identified: group 1 was p53 +/p53 mutated (five cases, all with p53 missense mutations). Morphologically, three of the five cases were composed of large cells. All five cases revealed overexpression of p53 in the majority of the tumor cells with a mean of 86%. Unexpectedly, three of these cases also showed overexpression of p21. Four of the five patients presented with clinical stage IVB and died with disease. Group 2 was p53+/p53 wild-type (10 cases). Histologically, nine cases were of the mixed type, and one of the large cell type. The percentage of p53 overexpressing cells was lower than in the previous group with a mean of 23%. p21 was positive in 7 of the 10 cases. Six patients in this group presented with clinical stages I to II and four patients with advanced disease (stage III and IV). Five patients are alive 12 to 120 months later (mean, 24 months), three with no evidence of disease. Group 3 was p53-/p53 wild-type (10 cases). All cases showed mixed cell morphology. p21 was positive in 5 of 10 cases. Four patients presented with clinical stage I to II and six patients with advanced disease. Four patients are alive with no evidence of disease 9 to 60 months later (mean, 10 months). Overall, p53 mutations were present in 24% (5 of 21) of the evaluable cases, all of them overexpressing p53 in the majority of tumor cells. Cases with p53 mutations were associated with large cell morphology (P = 0.0162) and presented more often with advanced stage disease. Loss of heterozygosity at chromosome 17p was found only in 2 of the 12 (17%) cases investigated, both cases showed p53 mutations of the remaining allele. P21 overexpression (60% of cases) is frequent in nasal NK/T-cell lymphoma and seems to be independent of p53 gene status. The overexpression of p53 and p21, independent of p53 mutations, although as yet not clear, might be the result of Epstein-Barr virus infection, and warrants further investigation.

Peripheral T/NK-cell lymphoma: a report of the IXth Workshop of the European Association for Haematopathology

AIMS

In April 1998, The European Association for Haematopathology organized the IXth workshop on peripheral T-cell and NK-cell lymphomas and leukaemias. The workshop focused on unusual subtypes of these rare malignancies, allowing evaluation of the recently published WHO classification of neoplastic diseases of the lymphoid tissues.

METHODS AND RESULTS

One-hundred and three cases were centrally immunophenotyped and hybridized for EBER1/2 of Epstein--Barr virus. All cases were reviewed by a panel of experienced haematopathologists and classified according to the new WHO classification for lymphoid neoplasms. Three cases were considered as precursor T-cell and 95 cases as peripheral T/NK-cell lymphoma/leukaemia. Although the cases represented a selected series of unusual cases, the following conclusions could be made: (i) Most lymphomas except the hepatosplenic gamma/delta T-cell lymphomas showed a rather broad morphological spectrum, with differences both between and within individual tumours. (ii) This heterogeneity was also reflected by the immunophenotype, for instance a variable expression of CD30 was found in many enteropathy type T-cell lymphomas. (iii) Exceptions in phenotype were regularly found in almost all categories, indicating that phenotype should not be the final determining factor in classification. (iv) The great majority of T-cell lymphomas expressed the alpha/beta T-cell receptor, with the exception of all but one hepatosplenic T-cell lymphomas and a few other extranodal peripheral T cell lymphomas. (v) Malignancies of precursor cells, blastic NK-cell lymphoma/leukaemia, adult T-cell lymphoma/leukaemia and most AIL-type T-cell lymphomas did not express cytotoxic molecules such as TIA1 and granzyme-B. In contrast, all five aggressive NK/T-cell lymphomas/leukaemias, a single case of large granular lymphocyte leukaemia and 40 of 47 primary extranodal lymphoma/leukaemias expressed these molecules. In hepatosplenic gamma/delta T-cell lymphoma, five of six cases showed expression of TIA1 but not of granzyme-B. (vi) Seven tumours developed after organ-transplant, four cases being EBV-positive. No distinct phenotype could be attributed to these cases.

CONCLUSIONS

Most peripheral T/NK cell lymphomas could be categorized as distinct entities as described in the recently proposed WHO classification for lymphoid neoplasms.

Clinicopathological features of Epstein-Barr virus-associated nasal T/NK cell lymphomas in southern Japan

OBJECTIVE

Nasal T/natural killer cell lymphomas (NTCL) are highly prevalent among Oriental populations. However the characteristic immunophenotype of NTCL is still controversial and it can be difficult to make a firm histologic diagnosis of malignancy. Therefore, 14 cases of NTCL in patients from southern Japan were evaluated for clinicopathological features and immunophenotypic status. Furthermore, the genetic variations in the latent membrane protein 1 (LMP-1) gene of Epstein-Barr virus (EBV)-related NTCL were evaluated.

METHODS

Biopsy specimens were fixed in formalin and embedded in paraffin before examination using in situ hybridization for EBV-encoded RNA-1 (EBER-1) as well as immunohistochemical staining for CD3, CD3epsilon, CD4, CD8, CD43, CD45RA, and CD45RO. To detect genetic variations, single-strand conformation polymorphism (SSCP) analysis and DNA sequencing were applied.

RESULTS

Clinically, 14 cases were divided into two groups. The first group consisting of eight patients showed good prognosis. The other group consisting of six patients showed poor prognosis. The vast majority of neoplastic cells in NTCL were EBER-1 positive. These cells did not express CD4, CD8, or CD45RA, but often expressed CD43 and CD45RO. In addition, they were negative for CD3 when stained with a mouse monoclonal antibody but stained for CD3epsilon when a rabbit polyclonal was used. The 3'-terminal of LMP-1 gene of seven cases were amplified and all of them have 30 base pair (bp) deletion.

CONCLUSION

NTCL are a heterogeneous mix of cell types although EBV-associated NTCL in patients from southern Japan appear to originate from natural killer cells rather than T cells, and also prognosis is variable and not always poor. The ability to make a firm diagnosis can be enhanced through the combined use of in situ hybridization and immunohistochemistry. High prevalence of the 30-bp deletions of the LMP-1 gene in EBV-related NTCL may also reflect the prevalence of the deletion variant in the normal population in Japan.

Lymphomatous features of aggressive NK cell leukaemia/lymphoma with massive necrosis, haemophagocytosis and EB virus infection

AIMS

Aggressive natural killer (NK) cell leukaemia will be categorized as a distinct entity in the new WHO classification of malignant lymphomas. However, its non-leukaemic features remain unclear. We therefore investigated the morphological and immunophenotypic features of this lymphoma.

METHODS AND RESULTS

Four cases with aggressive NK cell lymphoma were morphologically and immunohistochemically studied. All cases followed an aggressive course with death occurring within about 3 months of initial presentation. In these cases, the neoplastic cells disseminated throughout systemic lymph nodes and invaded various tissues and organs. The lymphoma cells were large cells showing nuclear irregularity and a pattern of sinusoidal invasion in lymph nodes. Apoptosis and coagulation necrosis were both frequently observed. Haemophagocytosis was observed in all cases. Neoplastic cells in paraffin-embedded tissue specimens from these patients had CD3(CD3epsilon)+ CD56(123C3)+ granzyme+ TIA-1+ EBERT+ CD43(MT1)- CD45RO(UCHL-1)- CD57(Leu7)- CD20(L26)- phenotypes. In the two cases where tissue was available for immunohistochemical study in frozen sections, neoplastic cells showed CD56(Leu19)+ perforin+ Fas ligand(FasL)+ CD2(Leu5b)- CD3(Leu4)- CD4(Leu3)- CD5(Leu1)- CD7(Leu9)- CD8(Leu2)- betaF1- TCRdelta1- phenotypes. CD16(Leu11b) was positive in one case.

CONCLUSIONS

: Natural killer cell lymphomas appear to represent a non-leukaemic counterpart of aggressive natural killer cell leukaemia, a relationship similar to that in adult T-cell leukaemia/lymphoma. Awareness and diagnosis of this aggressive lymphoma is important because of its fulminant course.

Primary nasal and nasopharyngeal lymphomas: a comparative study of clinical presentation and treatment outcome

Primary nasal lymphoma (NSL) and nasopharyngeal lymphoma (NPL) are uncommon extranodal lymphomas that have often been grouped together in studies published in the literature. It is unclear whether or not NSL and NPL are biologically different entities. We reviewed the records of 25 NSL and 19 NPL patients who were managed between 1985 and 1995, to evaluate and compare their clinical characteristics and treatment outcome. Clinical variables, including age, sex, stage, tumour bulk and treatment modality, were assessed for their prognostic influence on survival. Nasal obstruction (80%), nasal discharge (64%) and epistaxis (60%) were the predominant symptoms in NSL patients; neck swelling/mass (42%), nasal obstruction (37%) and hearing impairment (32%) were common findings in NPL patients. Limited stage disease (I/II) was present in all NSL and in 80% of the NPL patients. Thirty-six per cent of the NSL and 32% of the NPL patients had bulky disease. The majority of the immunophenotyped NSLs were of T-cell lineage (75%, 12/16) and most immunophenotyped NPLs were of B-cell lineage (69%, 11/16). The patients were treated with radiotherapy alone (14%), chemotherapy alone (23%) or chemotherapy plus radiotherapy (64%). NSL patients showed a lower complete remission rate and higher relapse rate than NPL patients, although the difference did not reach statistical significance. Both the 5-year disease-free survival (36% versus 76%; P = 0.007) and overall survival (33% versus 82%; P = 0.003) were significantly worse in NSL compared with NPL patients. Advanced age (>60 years; P = 0.03) and bulky disease (P = 0.04) were also associated with inferior survival times. The analysis of sex, stage and type of therapy showed no evidence of significant impact on the survival. Despite the close anatomical relationship in origin, NSL and NPL were noted to behave as biologically distinct entities, in which the NSLs demonstrated a higher frequency of T-cell tumours and a much worse prognosis than NPL. In addition to the primary site, advanced age and bulky disease were also associated with reduced survival.

Angiocentric lymphoma of the head and neck: patterns of systemic failure after radiation treatment

PURPOSE

To investigate the patterns of systemic failure and the clinical outcome in patients with angiocentric lymphoma of the head and neck who were treated with radiation alone, and to discuss the optimal mode of treatment for these patients.

PATIENTS AND METHODS

We reviewed the records of 92 patients with stage I or II angiocentric lymphoma who were treated at Yonsei Cancer Center between 1976 and 1994. All patients were treated with involved-field irradiation. Radiation doses ranged from 40 to 60 Gy (median dose, 50.4 Gy). Treatment response, patterns of treatment failure including systemic failure, and clinical outcome after radiation treatment were analyzed.

RESULTS

The most frequently involved site was the nasal cavity, either alone or in conjunction with other sites. In 16 patients (17.4%), angiocentric lymphoma was accompanied by cervical lymphadenopathy. Disease was classified as stage I in 62 patients (67.4%) and stage II in 30 patients (32.6%). After completion of radiation treatment, 61 patients (66.3%) achieved a complete response and 16 (17.4%) a partial response. Half of the patients (50.0%) ultimately experienced local recurrence with or without other components of failure, whereas regional failure was relatively uncommon (10.9%). Systemic failure occurred in 25.0% of patients during follow-up. Six patients had histologic findings identical to those at the time of the original disease (group I), whereas four patients exhibited morphologic features of frank lymphomas (group II). The majority of patients with systemic relapse had the predilection sites for widespread extranodal involvement, such as the skin, brain, lung, gastrointestinal tract, or testes. In addition, seven patients died from various medical illnesses or immunologic disorders, including hemophagocytic syndrome and second primary cancers (group III). After a median follow-up of 56 months, the overall survival and disease-free survival rates for all patients were 40.1% and 37.8%, respectively. All patients except one with systemic failure died within 1 year.

CONCLUSION

Treatment with radiation alone had suboptimal results, partly because of the occurrence of a variety of systemic failure with diverse clinicopathologic features. Given the frequent occurrence of systemic failure after radiation treatment, we believe that the multimodality treatment approach containing more effective chemotherapeutic agents should be incorporated in the treatment of angiocentric lymphoma confined to the head and neck.

Nasal lymphomas in Japan: a high prevalence of Epstein-Barr virus type A and deletion within the latent membrane protein gene

The majority of nasal lymphomas are of the natural killer (NK)/T cell lineage. We analyzed 33 specimens of nasal lymphoma from Japanese patients for Epstein-Barr virus (EBV). Phenotypic and genetic analyses showed 28 cases with NK/T cell type and 5 cases with B cell type. All NK/T lymphomas were of pleomorphic cell type except 2 large cell (centroblastoid) and one lymphoblastic lymphoma. All cases with nasal B cell lymphoma were of large (centroblastoid) cell type. EBV was detected in all cases of NK/T cell type with the exception of one lymphoblastic case, and was monoclonally integrated in all cases examined (14/14 cases). All but one case had subtype A of EBV infection with 30-base paired deleted LMP-1 gene. One case of B cell lymphoma showed the presence of EBV infection with subtype A and deletion of LMP-1. Our results indicate that the majority of nasal lymphomas in Japanese patients are of the nasal NK/T cell type, have pleomorphic morphology, a high prevalence of EBV with a monoclonal integration, subtype A and deleted LMP-1 gene. In contrast, nasal B cell lymphoma showed monomorphic appearance and rare EBV infection.

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.

Malignancies of natural killer (NK) cell precursor: myeloid/NK cell precursor acute leukemia and blastic NK cell lymphoma/leukemia

Malignant hematolymphoid disorders arising from natural killer (NK) cells have become widely recognized in the past decade. Recently, we as well as others have drawn attention to some neoplasms of conceivable NK cell precursor origin that might represent two distinct entities, i.e. myeloid/NK cell precursor acute leukemia and blastic NK cell lymphoma/leukemia. Both of these diseases were characterized by remarkable extramedullary involvement and lymphoblastoid morphology, although the sites of involvement differed. Myeloid/NK cell precursor acute leukemia exhibited more frequent involvement of bone marrow (BM) and lymph nodes, whereas blastic NK cell lymphoma/leukemia affected extranodal sites, mainly the skin/subcutis. Tumor cells of these two diseases shared the CD16-, CD56+ and CD57- phenotype, but differed in other phenotypic profiles. Indeed, myeloid/NK cell precursor acute leukemia was immunophenotypically characterized by the expression of CD34 and blastic NK cell lymphoma/leukemia by that of CD4. On the theoretical level in the NK cell differentiation pathway, myeloid/NK cell precursor acute leukemia might be derived from a myeloid antigen-positive precursor preceding a NK cell committed precursor as a conceivable counterpart of blastic NK cell lymphoma/leukemia. Most cases with either disease lacked cytotoxic activities or molecules, a finding which seems to support their precursor origin. Notably, Epstein Barr virus (EBV) was negative in all cases, which contrasted with its high level associated with mature NK cell malignancies. Chemotherapy for acute myeloid leukemia was generally effective for myeloid/NK cell precursor acute leukemia, while the regimen for lymphoid malignancy was effective for blastic NK cell lymphoma/leukemia. These data suggests that each of these two diseases constitutes a distinct entity, which is also different from mature NK cell malignancies.

Immunophenotypic and genotypic characterization of nasal lymphoma with polymorphic reticulosis morphology

Nasal lymphoma with polymorphic reticulosis (PR) morphology is now categorized as T/natural killer (T/NK) cell lymphoma. In this study, immunophenotypes and genotypes of proliferating cells in 21 cases with PR were examined. The patients included 13 men and 8 women ranging in age from 20 to 74 (median 37) years. All patients presented with lesions in the upper respiratory tract, mostly in the nasal cavity. Histological specimens obtained from the primary lesions (19 cases) and metastatic cervical lymph nodes (2 cases) were used for analyses. Histologically, polymorphous proliferation was found in 20 cases, and these were thus diagnosed as PR. A monomorphous pattern was found in the remaining last case. Immunohistochemical analysis revealed that the proliferating cells were CD56 (123C3)+ and/or CD16 (2H7)+, TIA-1+ and frequently stained CD3 epsilon+. Tumor cells were frequently stained positively with monoclonal antibodies (mAbs) for T lymphocytes, but were negative for T-cell receptor (TCR) beta and delta chain expression. In situ hybridization analysis using an Epstein-Barr virus-encoded early RNA 1 (EBER-1) probe revealed positive signals in 13 of the 15 cases examined. Southern blotting analysis for clonality of the Epstein-Barr virus (EBV) genome in 12 positive cases confirmed the presence of monoclonal proliferation in 7 cases. The pattern of TCR gamma chain gene rearrangement was examined by PCR analysis of DNA from tumor tissues by the denaturing gradient gel electrophoresis method. The results demonstrated no clonal rearrangement in any of the 21 cases examined, including 7 cases with proven clonal proliferation of EBV-infected cells, indicating the absence of T-cell clones. Our findings strongly suggested that nasal T-cell lymphoma is in fact a NK cell lymphoma.

Practical applications of immunohistochemistry in hematolymphoid neoplasms

Immunohistochemistry plays a key role in the diagnosis and classification of hematolymphoid neoplasms. New cell and lineage markers are constantly being discovered and added to the existing long list of antibodies. In this review article we provide general information and new applications of the commonly used hematolymphoid markers. We also discuss the features and applications of some newly discovered markers, such as ALK, fascin, granzyme/perforin, and tryptase. There is no universal "panel" for the diagnosis of hematolymphoid neoplasms. However, in this review article, we provide suggested panels for a given hematolymphoid neoplasm that is based on our experience and that reported in the literature.

The expression of TIA-1+ cytolytic-type granules and other cytolytic lymphocyte-associated markers in CD30+ anaplastic large cell lymphomas (ALCL): correlation with morphology, immunophenotype, ultrastructure, and clinical features

Anaplastic large cell lymphomas (ALCL) are a heterogeneous group of CD30+ large cell lymphomas; the most characteristic type have a T or null cell phenotype, often express epithelial membrane antigen (EMA) and cytolytic lymphocyte markers, and often possess a nonrandom t(2;5)(p23;q35) chromosomal translocation. We studied 22 (19 T, 1 null, 2 B cell) ALCL, including four primary cutaneous ALCL (PC-ALCL), for the expression of TIA-1, the cytotoxic T lymphocyte (CTL) or natural killer (NK) cell-associated antigens CD4, CD8, betaF1, TCRdelta1, CD56, and CD57, the ALCL-associated antigens p80 and EMA, and the Hodgkin's disease-associated marker CD15 to better define the relationship of these markers to histological subtype, primary site, and patient clinical characteristics. TIA-1 expression was seen in 12 of 20 (60%) T or null cell ALCLs with a cytoplasmic, granular distribution. Ultrastructural studies showed cytotoxic-type granules (dense core, multivesicular, and intermediate types) with TIA-1 localized to granules on immunogold labeling. TIA-1 staining strongly correlated with young patient age (< or = 32 years, P < .05) and EMA expression (P < .05). Excluding the four PC-ALCL cases, TIA-1 staining also correlated with p80 expression (P < .05) in all of the T cell cases. Three CD15+ cases were TIA-1-. TIA-1 expression in T or null cell ALCL was seen in all morphological subtypes (2 of 2 small cell variant, 3 of 4 monomorphic variant, and 7 of 14 pleomorphic variant) and primary tumor sites (6 of 14 nodal, 2 of 4 primary cutaneous, 2 of 2 bone, and 2 of 2 soft tissue). TIA-1+ granules were seen in all subsets: 5 of 6 CD4+, 1 of 2 CD8+, 4 of 8 CD56+, and 1 of 2 CD57+ ALCL. Of note, 4 of 10 T or null cell ALCL expressed gammadelta T-cell receptors (TCR), whereas only 1 of 10 T or null cell ALCL was alphabeta TCR+; TCR were not detected in five cases. TIA-1 was expressed by 3 of 4 gammadelta TCR+ ALCL and 1 of 1 alphabeta TCR+ ALCL. These data support a cytotoxic lymphocyte phenotype in most T or null cell ALCL and suggest that some T cell ALCL are derived from cytolytic CD4+ T cells, gammadelta T cells, or NK-like (CD56+ or CD57+) T cells.

Peripheral T and putative natural killer cell lymphomas commonly coexpress CD95 and CD95 ligand

The CD95 (Fas)/CD95 ligand (CD95L) system is an important mechanism triggering apoptosis, and CD95L expression has recently been implicated for immune evasion and aggressive behavior in malignancies. This study aimed to investigate CD95 and CD95L expression in lymphomas and the possible relationship with tumor cell apoptosis, with emphasis on the natural killer (NK) cell lymphomas, which are highly aggressive neoplasms and frequently exhibit tumor cell apoptosis/necrosis. Frozen sections of 82 cases of lymphomas obtained from Queen Elizabeth Hospital and Caritas Medical Center, Hong Kong, were immunostained with polyclonal anti-CD95 and anti-CD95L antibodies. The NK-cell lymphomas were also studied for apoptosis by in situ end labeling (ISEL) method, and zonal tumor cell death was evaluated semiquantitatively. The cases studied included 27 NK-, 22 T-, and 33 B-cell lymphomas. CD95 was expressed in 25 (93%) NK-, 11 (50%) T-, and 14 (42%) B-cell lymphomas. CD95L was expressed in 19 (70%) NK-, 15 (68%) T-, and 3 (9%) B-cell lymphomas. There was significant difference in the frequency of CD95 expression between B- and NK- (P < .001), and between T- and NK-cell lymphomas (P < .05), and in CD95L expression between B- and T- (P < .01) or NK-cell (P < .01) lymphomas. Zonal tumor cell death was present in 21 (78%) NK-cell lymphomas and 1 (4.5%) T-cell lymphoma and showed no correlation with CD95 or CD95L expression. ISEL analysis showed apoptosis predominantly in the viable areas in only 5 (24%) NK-cell lymphomas. In conclusion, CD95L is frequently expressed in NK- and T-cell lymphomas, but rarely in B-cell lymphomas. Zonal tumor cell death is not correlated with CD95 or CD95L expression and thus the CD95/CD95L system probably does not contribute significantly to this phenomenon. We postulate that the frequent expression of CD95L by NK- and T-cell lymphomas may mediate local or systemic tissue damage and immune evasion, and may contribute to the clinical aggressiveness of these tumors.

Treatment of localized non-Hodgkin's lymphomas of the head and neck: focusing on cases of non-lethal midline granuloma

This report clarifies the prognostic factors for survival in localized non-Hodgkin's lymphoma (NHL) of the head and neck and defines optimal regimens for this disease. One hundred-seven untreated patients with Stage I or II NHL of the head and neck were treated with involved field radiation therapy for orbital, nasal, or paranasal lymphoma and extended field radiation for Waldeyer's ring or neck lymphoma. Radiation doses were 39-48 Gy. In the latter half of the study, adjuvant chemotherapy was administered. Of 107 patients, 95 achieved complete response (CR). Of the 12 patients that did not achieve CR, 9 had nasal T-cell lymphoma (NTL) of the lethal midline granuloma type (LMG-NTL). Only one patient who obtained CR relapsed in a previously irradiated area. Age, sex, stage, bulky mass, number of involved sites, LMG-NTL, histologic subtypes, radiation dose, and adriamycin dose were analyzed for prognostic significance for disease-specific survival in NHL by multivariate analysis. LMG-NTL was the most significant prognostic factor (P < 0.001). Patients with higher age also experienced a higher relative risk than patients of > or =60 years of age (P = 0.0063). Dose of adriamycin reached the borderline significance (P = 0.0600). Radiotherapy is excellent for obtaining local control of head and neck NHL. Randomized trials are required to determine the appropriate radiation field and dose in patients previously treated with chemotherapy. LMG-NTL and age were the significant prognostic factors for disease-specific survival.

Natural killer cell lymphoma in cytology: breaking all the rules--a case report

A testicular mass aspirate was received from a 22-yr-old patient with known non-Hodgkin's lymphoma. The cells were large and pleomorphic, occurring in syncytial fragments and demonstrating abundant cytoplasm. No lymphoglandular bodies were seen. As characteristic lymphoma criteria were not present, a cytodiagnosis of germ-cell tumor was suggested, and testicular biopsy advised. The final histopathology report, however, was of a CD 56-positive (large-cell) T-natural killer cell lymphoma, of which this appears to be the first example described and illustrated cytologically.

Application of the polymerase chain reaction for the diagnosis of malignant lymphoma of the nasal and oral cavities

Difficulties are often encountered in the diagnosis of malignant lymphoma of the oral and nasal cavities by histology and immunohistochemistry because these malignancies may be complicated by inflammation and necrosis. In the present study, immunoglobulin heavy chain (IgH) and T-cell receptor (TCR) gene rearrangements were examined by the polymerase chain reaction (PCR) in formalin-fixed and paraffin-embedded specimens obtained from 18 patients; the advantages of this method were evaluated. Twelve of these patients were diagnosed as having malignant lymphoma and six had tumors highly suggestive of malignant lymphoma. Fourteen (78%) of the 18 cases were diagnosed as malignant lymphoma histologically and immunohistochemically. Sixteen (89%) of the 18 cases were shown to be monoclonal by PCR. The four cases that could not be histologically or immunohistochemically diagnosed as malignant lymphoma showed monoclonal gene rearrangement by PCR. As a result, six patients suspected of having a malignant lymphoma were diagnosed as having one. The diagnosis of malignant lymphoma by PCR alone still has various problems. However, when the results of PCR are evaluated together with histopathological and immunohistochemical results, PCR makes a useful contribution to the diagnosis of malignant lymphomas of the nasal and oral cavities.

CD56+ putative natural killer cell lymphomas: production of cytolytic effectors and related proteins mediating tumor cell apoptosis?

Apoptosis is a regulated form of cell death that may be triggered by natural killer (NK) or cytotoxic T cells, which effect target cell lysis by cytolytic effector and related proteins through complex intracellular signals. This study was aimed to investigate whether there is selective expression of these cytolytic markers in the putative NK-cell lymphomas and whether there is correlation with zonal tumor cell death in these tumors. Expression of the cytolytic effectors perforin, granzyme B9, and the granule membrane protein TIA1 were examined in 24 putative NK-cell lymphomas, 18 postthymic T-cell lymphomas (one case CD8+ CD56+ and three anaplastic large cell lymphomas (ALCL), three T-lymphoblastic lymphomas, and 20 B-cell lymphomas. Nineteen (79%) putative NK-cell lymphomas expressed perforin, and all 24 cases expressed granzyme B9 and TIA1. The only CD8+ CD56+ postthymic T-cell lymphoma also expressed all three cytolytic markers, two CD8- ALCL expressed TIA1; other postthymic T-cell, T-lymphoblastic, and B-cell lymphomas were consistently negative. There was strong correlation between percentage perforin-positive cells and zonal tumor cell death. Angioinvasion, in contrast, was present only in a proportion (37%) of these lymphomas despite the frequent presence of zonal tumor cell death (71%). We propose that cytolytic effector and related proteins produced by putative NK and some CD8+ CD56+ postthymic T-cell lymphomas, probably in conjunction with other mechanisms, may effect massive tumor cell apoptosis. The frequent expression of cytolytic effector markers in the CD2+ surface CD3- CD56+ putative NK-cell lymphomas lends further support to their probable NK cell origin.

CD56-positive (nasal-type T/NK cell) lymphoma arising on the skin. Report of two cases and review of the literature

Several authors have reported cases of patients with malignant lymphoma with unique characteristics, designated nasal-type T/NK cell lymphoma, which expresses the natural killer (NK) cell marker and shows frequent extra-nodal involvement and poor prognosis. We report 2 cases of this type of lymphoma which were CD56-positive and showed a histopathologically angiocentric pattern with cutaneous and subcutaneous tumorous lesions. Patient 1 had extensive invasion of skin, underlying skeletal muscle, spleen and bone marrow, and died of sepsis 34 months after onset. Patient 2 had multiple subcutaneous nodules and invasion to mammary gland, lung, lymph node and spleen at the time of her first visit. She died of a rapid invasion of lymphoma cells to the liver 5 months after onset. Both patients showed similar immunophenotypes of tumor cells (CD2+, CD3-, CD4-, CD8-, CD20-, CD56+) and germ line configuration of the heavy chain of immunoglobulin (JH), T-cell receptor C beta-1 subunit DNA and T-cell receptor J gamma subunit DNA. Epstein-Barr virus early regions RNA was demonstrated in the nuclei of tumor cells of both patients with in situ hybridization. The histopathological examination of the skin lesions of both patients revealed the features of angiocentric lymphoma. The detection of CD56 in the tumor cells of cutaneous lymphomas should be routinely performed for the early diagnosis of this type of lymphoma with extremely poor prognosis.

CD56/neural cell adhesion molecule expression in primary extranodal Ki-1/CD30+ lymphoma. Report of a pediatric case with simultaneous cutaneous and bone localizations

We describe the clinicopathologic features of an unusual case of CD30+/CD50+ T-cell lymphoma in a child who presented with simultaneous primary extranodal cutaneous and bone localizations. The expression of CD56 (neural cell adhesion molecule, or NCAM) is rare in non-Hodgkin's lymphomas other than in a group of haematopoietic/lymphoid neoplasms of natural killer and natural killer-like T-cells, which usually involve extranodal sites and often pursue an aggressive clinical behavior. Coexpression of CD30 and CD56 in T-cell lymphomas is exceedingly rare, and its biological significance is unknown. Our patient responded well to an intensive chemotherapy regimen, and she is now in complete remission 4 years after discontinuation of chemotherapy. Expression of NCAM could be regarded as responsible, in part, for the extranodal localization of lymphoma cells; expression of CD56 also might contribute to the definition of a subset of CD30+ lymphomas with distinctive clinicopathologic features.

Extranodal head and neck lymphomas in Guatemala: high frequency of Epstein-Barr virus-associated sinonasal lymphomas

Sinonasal lymphomas of T cell or natural killer cell (T/NK cell) phenotype represent a subset of extranodal head and neck lymphomas. T/NK cell sinonasal lymphomas have been described in diverse geographic settings, including China, Japan, Peru, Northern Europe, and North America. The frequency of these lymphomas is highly dependent on the geographic location in which they occur, their incidence being low in Europe and North America and relatively high in Asian countries and in Peru. Regardless of their geographic location, they are typically associated with the Epstein-Barr virus (EBV). Few studies have addressed the relative frequency of sinonasal lymphoma within the group of extranodal head and neck lymphomas. We investigated the anatomic distribution, immunophenotypical profile, and EBV status of 33 cases of extranodal head and neck lymphoma from patients in Guatemala. The anatomic distribution of these lymphomas is similar to that seen in Asian countries: 17 (52%) in the sinonasal area, five (15%) in the palate, and 11 (33%) in other locations. Fifteen (88%) of the 17 sinonasal lymphomas showed a T or null cell phenotype with a strong association with EBV by in situ hybridization. Most Guatemalan patients with these lymphomas were of Mayan descent. In Guatemala, the relative frequency of sinonasal lymphomas within the group of head and neck lymphomas is significantly higher than that reported for Western countries. In addition, the relative frequency of T/NK versus B cell sinonasal lymphomas is higher than that described in North America and similar to that observed in Asian countries and Peru.

Nonnasal Lymphoma Expressing the Natural Killer Cell Marker CD56: A Clinicopathologic Study of 49 Cases of an Uncommon Aggressive Neoplasm

Expression of the natural killer (NK) cell antigen CD56 is uncommon among lymphomas, and those that do are almost exclusively of non–B-cell lineage and show a predilection for the nasal and nasopharyngeal region. This study analyzes 49 cases of nonnasal CD56+ lymphomas, the largest series to date, to characterize the clinicopathologic spectrum of these rare neoplasms. All patients were Chinese. Four categories could be delineated. (1) Nasal-type NK/T cell lymphoma (n = 34) patients were adults 21 to 76 years of age (median, 50 years), including 25 men and 9 women. They presented with extranodal disease, usually in multiple sites. The commonest sites of involvement were skin, upper aerodigestive tract, testis, soft tissue, gastrointestinal tract, and spleen. Only 7 cases (21%) apparently had stage I disease. The neoplastic cells were often pleomorphic, with irregular nuclei and granular chromatin, and angiocentric growth was common. The characteristic immunophenotype was CD2+ CD3/Leu4− CD3ε+ CD56+, and 32 cases (94%) harbored Epstein-Barr virus (EBV). Follow-up information was available in 29 cases: 24 died at a median of 3.5 months; 3 were alive with relapse at 5 months to 2.5 years; and 2 were alive and well at 3 and 5 years, respectively. (2) Aggressive NK cell leukemia/lymphoma (n = 5) patients presented with hepatomegaly and blood/marrow involvement, sometimes accompanied by splenomegaly or lymphadenopathy. The neoplastic cells often had round nuclei and azurophilic granules in the pale cytoplasm. All cases exhibited an immunophenotype of CD2+ CD3/Leu4− CD56+ CD16− CD57− and all were EBV+. All of these patients died within 6 weeks. (3) In blastoid NK cell lymphoma (n = 2), the lymphoma cells resembled those of lymphoblastic or myeloid leukemia. One case studied for CD2 was negative and both cases were EBV−. One patient was alive with disease at 10 months and one was a recent case. (4) Other specific lymphoma types with CD56 expression (n = 8) included one case each of hepatosplenic γδ T-cell lymphoma and S100 protein+ T-cell lymphoproliferative disease and two cases each of T-chronic lymphocytic/prolymphocytic leukemia, lymphoblastic lymphoma, and true histiocytic lymphoma. All of these cases were EBV−. Six patients died at a median of 6.5 months. Nonnasal CD56+ lymphomas are heterogeneous, but all pursue a highly aggressive clinical course. The nasal-type NK/T-cell lymphoma and aggressive NK cell leukemia/lymphoma show distinctive clinicopathologic features and a very strong association with EBV. Blastoid NK cell lymphoma appears to be a different entity and shows no association with EBV.

Natural killer cell lymphoma/leukemia: pathology and treatment

Malignancies arising from cells of putative natural killer (NK) cell origin have increasingly been recognized as distinct clinicopathological entities. These malignancies are marked by tumour cells with NK cell characteristics, including the immunophenotype of CD2+, surface CD3-, cytoplasmic CD3 epsilon+, CD7 +/-, and CD56+, and the genotype of germline T cell receptor gene. A consistent association with monoclonal Epstein-Barr virus infection in the tumour cell has been observed. These tumours are now regarded as putative NK cell lymphoma/leukemia. Pathologically, tumour cells show variable cytological appearances, with frequent angiocentricity and angioinvasion, associated with zonal necrosis. Clinically, most cases occur in the nasal area and upper aerodigestive tract. However, occurrence in non-nasal sites such as the skin, gastrointestinal tract and testis is also observed. A particularly aggressive form of NK lymphoma/leukemia presents fulminantly as disseminated disease sometimes with a leukemic phase. All types of NK lymphoma/leukemia have an extremely poor prognosis with a median survival of less than a year. New modalities of treatment, including the use of high dose chemotherapy and stem cell rescue may be needed to improve treatment outcome.

A New Subtype of Large B-Cell Lymphoma Expressing the ALK Kinase and Lacking the 2; 5 Translocation

Seven cases of large B-cell lymphoma which define a previously unrecognized subgroup are reported. Morphologically they are comprised of monomorphic large immunoblast-like cells, containing large central nucleoli, which tend to invade lymphatic sinuses. Superficially they resemble anaplastic large cell lymphoma (ALCL) but they lack CD30. These lymphomas express epithelial membrane antigen (as do ALCL), but also contain intracytoplasmic IgA of a single light chain type (five cases) and an endoplasmic reticulum–associated marker detected by antibody VS38. They lack lineage-associated leukocyte antigens with the exception of CD4 (5 of 5 cases) and CD57 (5 of 7 cases). They are labeled by antibodies detecting both the intracytoplasmic and extracellular regions of the ALK receptor kinase, suggesting that they express the full-length form of this molecule. This was confirmed by Western blotting (in the one case tested) which showed a band of 200 kD in tumor cell lysates, and by polymerase chain reaction (PCR) amplification of mRNA encoding intracellular and extracellular ALK sequences (in the two cases tested). There was no evidence by cytogenetics (one case analyzed) or reverse transcriptase-PCR (three cases tested) of the 2; 5 translocation or the resultant NPM-ALK gene, as is commonly found in ALCL. All but one of the patients were male and all but one were adults, and in all but the latter case the disease followed an aggressive course.

A New Subtype of Large B-Cell Lymphoma Expressing the ALK Kinase and Lacking the 2; 5 Translocation

Seven cases of large B-cell lymphoma which define a previously unrecognized subgroup are reported. Morphologically they are comprised of monomorphic large immunoblast-like cells, containing large central nucleoli, which tend to invade lymphatic sinuses. Superficially they resemble anaplastic large cell lymphoma (ALCL) but they lack CD30. These lymphomas express epithelial membrane antigen (as do ALCL), but also contain intracytoplasmic IgA of a single light chain type (five cases) and an endoplasmic reticulum–associated marker detected by antibody VS38. They lack lineage-associated leukocyte antigens with the exception of CD4 (5 of 5 cases) and CD57 (5 of 7 cases). They are labeled by antibodies detecting both the intracytoplasmic and extracellular regions of the ALK receptor kinase, suggesting that they express the full-length form of this molecule. This was confirmed by Western blotting (in the one case tested) which showed a band of 200 kD in tumor cell lysates, and by polymerase chain reaction (PCR) amplification of mRNA encoding intracellular and extracellular ALK sequences (in the two cases tested). There was no evidence by cytogenetics (one case analyzed) or reverse transcriptase-PCR (three cases tested) of the 2; 5 translocation or the resultant NPM-ALK gene, as is commonly found in ALCL. All but one of the patients were male and all but one were adults, and in all but the latter case the disease followed an aggressive course.