The World Health Organization classification of malignant lymphoma: incidence and clinical prognosis in HTLV-1-endemic area of Fukuoka

New insights into the pathogenesis of lymphoid malignancies have been gained through novel genetic, molecular and immunological techniques. A new classification system for lymphoid malignancies, known as the new World Health Organization (WHO) classification, has been proposed recently based on these findings. The relative incidence of the subtypes of malignant lymphoma is known to differ according to geographic location. Adult T-cell leukemia/lymphoma (ATLL) is a human malignancy associated with human T-cell leukemia virus type 1 (HTLV-1), and the Kyushu islands are an HTLV-1 endemic area. To clarify the relationship between the histological classification and prognosis of lymphoid malignancies, we reclassified previous cases in our department and summarized our previous reports using the WHO classification. Of 933 cases of lymphoid malignancies, 471 (50%) were B-cell lymphoma, 396 (42%) T/natural killer (NK)-cell lymphoma and 41 (4%) Hodgkin lymphoma (HL). Analysis of clinical outcome showed favorable prognosis for HL, intermediate for B-cell lymphoma and poor prognosis for T-cell lymphoma. Among B-cell lymphomas, the commonest type was diffuse large B-cell lymphoma (n = 281; 60%). Marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) was diagnosed in 82 cases (17%), follicular lymphoma in 52 (11%) and mantle cell lymphoma in 24 (5%). Other less common lymphomas were Burkitt lymphoma (n = 9; 2%) and lymphoblastic lymphoma (n = 5; 1%). Using overall survival rates, the various B-cell lymphoma types could be divided into three broad groups for prognostic purposes: (i) low-risk group comprising follicular lymphoma and MALT; (ii) intermediate-risk group comprising diffuse large B-cell lymphoma and Burkitt lymphoma; and (iii) high-risk group comprising mantle cell lymphoma and lymphoblastic lymphoma. Among the T/NK-cell lymphomas, the commonest type was ATLL (n = 191; 48%), followed by peripheral T-cell lymphoma, unspecified (n = 83; 21%), angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) (n = 38; 10%), anaplastic large cell lymphoma (ALCL) (n = 22; 6%). Less common types were lymphoblastic lymphoma (n = 17; 4%), nasal and nasal-type NK/T-cell lymphoma (n = 17; 4%), mycosis fungoides (MF) (n = 9; 2%) and other rare types. With respect to clinical prognosis, T/NK-cell lymphomas fell into three groups: (i) relative low-risk group comprising ALCL, AILD, MF and lymphoblastic lymphoma; (ii) relative intermediate-risk group comprising NK/T-cell lymphoma and unspecified lymphoma; and (iii) extremely high-risk group comprising ATLL. Among the lymphoblastic lymphomas, B-cell type and T-cell type lymphomas exhibited different clinical outcomes. We conclude that the histological, phenotypic and genotypic classification of the new WHO system should be beneficial for the clinical approach to these tumors.     

Adult T-cell leukemia/lymphoma in Jujuy,north-west Argentina

Human T-cell leukemia virus type 1 (HTLV-1) infection is prevalent in native Americans living in the Andes. Some of their malignant lymphomas (ML) show a peculiar histology suggestive of adult T-cell leukemia/lymphoma (ATLL). To determine whether ML resembling ATLL are indeed ATLL, re-analysis of 34 cases occurring in Jujuy, a province of Argentina, was conducted, concentrating on immunological phenotype, integration of HTLV-1 proviral DNA, expression of HTLV-1 p40Tax and p27Rex, and infection of Epstein-Barr virus (EBV). The ML were 22 cases of mature peripheral T-cell and natural killer (NK)-cell neoplasm (mT/NKN), 11 B-cell malignant neoplasms and one Hodgkin's lymphoma. Polymerase chain reaction against the HTLV-1 proviral DNA, using DNA extracted from paraffin sections, indicated integration of the HTLV-1 proviral DNA in three cases of eight mT/NKN. Two other cases of mT/NKN were positive for anti-HTLV-1 antibodies. Expression of p40Tax and p27Rex was detected in all five of these mT/NKN cases associated with HTLV-1. As such, these five mT/NKN were rediagnosed as ATLL. In situ hybridization signals for EBV-encoded small nuclear early region-1 were detected in nine cases of mT/NKN, of which five cases of NK-cell lymphoma were found to have cytoplasmic CD3 expression, a CD56 phenotype and positivity of TIA1. According to the new World Health Organization classification, the mT/NKN class includes five cases of ATLL and five cases of NK-cell lymphomas. The five cases of ATLL were of native American extraction from an HTLV-1-endemic area around Jujuy, north-west Argentina.     

Clusterin expression in malignant lymphomas: a survey of 266 cases.

Clusterin expression has been reported to be characteristic of systemic anaplastic large cell lymphoma and usually negative in cutaneous anaplastic large cell lymphoma as well as other lymphoma types. We surveyed clusterin expression using immunohistochemical methods in 266 cases of non-Hodgkin's lymphoma and Hodgkin's disease to further assess the diagnostic utility of this marker. Clusterin immunostaining was observed in 40 of 49 (82%) systemic anaplastic large cell lymphomas and 12 of 29 (41%) cutaneous anaplastic large cell lymphomas. Clusterin also was expressed in 5 of 43 (12%) diffuse large B-cell lymphomas (4 of 5 CD30+), 1 of 14 (7%) peripheral T-cell lymphomas, 1 of 32 (3%) cases of nodular sclerosis Hodgkin's disease, and 1 case of mycosis fungoides in large cell transformation. Clusterin was negative in all other neoplasms assessed including follicular lymphoma of all grades (n = 24), mantle cell lymphoma (n = 13), marginal zone B-cell lymphoma (n = 12), precursor T-cell or B-cell lymphoblastic leukemia/lymphoma (n = 10), mixed cellularity Hodgkin's disease (n = 8), chronic lymphocytic leukemia/small lymphocytic lymphoma (n = 7), Burkitt lymphoma (n = 7), mycosis fungoides (n = 4), nodular lymphocyte predominant Hodgkin's disease (n = 3), lymphoplasmacytic lymphoma/Waldenstrom macroglobulinemia (n = 2), and plasmacytoma (n = 2). We conclude that clusterin is a marker of anaplastic large cell lymphoma and that addition of clusterin to antibody panels designed to distinguish systemic anaplastic large cell lymphoma from classical Hodgkin's disease is useful. However, clusterin is also positive in a substantial subset of cutaneous anaplastic large cell lymphomas, a smaller subset of diffuse large B-cell lymphomas, and rarely in cases of peripheral T-cell lymphoma and nodular sclerosis Hodgkin's disease.     

Monoclonal antibody HML-1 reactivity with adult T-cell leukaemia/lymphoma and other lymphomas

Human T-cell leukaemia/lymphoma virus type 1 (HTLV-1), a causative virus of adult T-cell leukaemia/lymphoma (ATLL), is known to be transmitted by breast-feeding. Using a monoclonal antibody HML-1 which labels human intestinal intra-epithelial T lymphocytes, we have immunohistochemically examined ATLL tissues in order to evaluate the possibility that HTLV-1 infected intestinal T cells are the origin of ATLL cells. Previously this antibody was reported to react with intestinal T-cell malignant lymphomas but not with peripheral tumours, or any B-cell lymphomas. We investigated 181 patients with malignant lymphomas and found that 19 out of 113 ATLLs were positive for HML-1. T-cell malignant lymphomas excluding ATLL also reacted with HML-1 (7/24), but all the B-cell lymphomas 0/33) and non-neoplastic lymph node and skin lesions (0/10) were negative for HML-1. In patients with ATLL and other T-cell malignant lymphomas, the positivity level of HML-1 was relatively higher in stomach (3/7) and tonsil (2/6) than that in lymph nodes (15/100) and skin (8/47). We observed one HML-1 positive ATLL patient with tumour formation in the skin and lymphadenopathy and marked infiltration of the large intestine but minimal involvement of other organs. Although HML-1 was frequently expressed in gastric infiltration of ATLL, the level of positivity was too low in lymph nodes to support the hypothesis that HTLV-1 infected intestinal T cells are the origin of ATLL cells. Some of the HML-1 positive ATLL cases co-expressed CD30. Furthermore, three of six cases of Ki-1 lymphoma (large anaplastic cell lymphoma) were positive for HML-1. We conclude that expression of HML-1 in ATLL reflects an activated state of the lymphoma cells, but not the intestinal origin of ATLL cells.     

CD40 ligand is constitutively expressed in a subset of T cell lymphomas and on the microenvironmental reactive T cells of follicular lymphomas and Hodgkin's disease.

Although CD40 has been extensively studied in B- and T-cell non-Hodgkin's lymphomas (NHLs)/leukemias, and more recently in Hodgkin's disease (HD), little is known about the expression of its ligand (CD40L) in lymphoproliferative disorders other than T-cell NHLs/leukemias. A series of 121 lymphoma/leukemia samples, including 35 cases of HD, 34 T-cell and 39 B-cells NHLs, 2 cases of adult T-cell leukemia/lymphoma, and 11 cases of T-cell acute lymphoblastic leukemia, were evaluated for CD40L expression by immunostaining of frozen tissue sections and flow cytometry with the anti-CD40L monoclonal antibody M90. CD40L was constitutively expressed by neoplastic cells in 15 of 36 (42%) T-cell NHLs/adult T-cell leukemia/lymphomas, almost invariably those displaying the CD4+/CD8- phenotype, whereas no CD40L-expressing tumor cells could be found in B-cell NHL and HD. Among T-cell acute lymphoblastic leukemias, CD40L was detected only on 2 cases displaying a stem-cell-like phenotype. In follicular B-cell lymphomas a large number of CD40L-expressing CD3+/CD4+ T lymphocytes were found admixed with tumor cells within the neoplastic follicles and in their surrounding areas. In the nonfollicular B-cell lymphomas, CD40L-positive CD3+/CD4+ T lymphocytes were few or absent. In all HD subtypes other than the nodular lymphocytic predominance, CD40L-expressing CD3+/CD4+ T lymphocytes were numerous in the HD-involved areas and were mainly located in close proximity to the Reed-Sternberg cells. Our data indicate that in human lymphomas CD40L is preferentially expressed by a restricted subset of T-cell lymphomas, mostly with CD4 immunophenotype. Finally, we have provided morphological evidence that CD40L may play an important role in the cell contact-dependent interaction of tumor B-cells (CD40+) within the neoplastic follicles or Reed-Sternberg cells (CD40+) in HD-involved areas and the microenvironmental CD3+/CD4+/CD40L+ T lymphocytes.     

Risk of T-cell lymphomas in persons with AIDS

Lymphomas in persons with AIDS are mostly B-cell types, but T-cell lymphomas have also been reported. We examined T-cell lymphoma risk in the 2-year period after AIDS onset by linking 302,834 adults with AIDS to cancer registry data. Of 6,788 cases of non-Hodgkin's lymphoma (NHL) with specified histologies, 96 (1.4%) were T-cell lymphomas. Assessment was based on clinical diagnosis and histology because T-cell marker data were inadequate, but when present, marker data supported the T-cell diagnosis. The relative risk of T-cell lymphoma, estimated by standardized incidence ratio, was 15.0 (95% confidence interval: 10.0--21.7). Risks were increased for all subtypes, including mycosis fungoides, peripheral lymphomas, cutaneous lymphomas, and adult T-cell leukemia/lymphoma (ATLL). HIV-related immunodeficiency could be important, but differences between the population developing AIDS and the general population (e. g., immigration from the Caribbean region for ATLL) might independently increase T-cell lymphoma risk.     

Ultrastructural characteristics of malignant non-Hodgkin's lymphoma in baboons

The ultrastructure of 29 malignant non-Hodgkin's lymphomas of baboons including prolymphocytic lymphoplasmacytic, lymphoblastic, and immunoblastic malignant lymphomas is described. The ultrastructure of the cells of B-cell malignant lymphomas is characterized by a more developed strands system of rough endoplasmic reticulum in the tumor cell cytoplasm and the presence of structural abnormalities in the protein synthesis in some B-cell malignant lymphoma cells in the form of Russell's and Dutcher bodies. Analogous baboon and human tumors were shown to have a high degree of cell ultrastructure similarity. Rare forms of baboon malignant non-Hodgkin's lymphomas including a large-cell variant of T-cell lymphoblastic lymphoma with large multilobated nuclei and a variety of B-cell lymphoma with an intermediate degree of cell differentiation have been found. Malignant lymphoma of large multilobated T-cell type and lymphoma of the intermediate lymphocytic type occur rarely in human pathology too.     

Prevalence of human T-cell lymphotropic virus type 1 and 2 among patients with malignant hematological diseases in south Chile

Human T-cell lymphotropic virus type 1 and 2 (HTLV-1/2) are oncogenic retroviruses linked etiologically to human diseases. In Chile, these viruses have been studied in ethnic populations, or patients diagnosed clinically with HTLV-1 associated myelopathy/tropical spastic paraparesis, but have not been studied in patients with malignant hematological diseases. The aim of this study was to determine the seroprevalence and viral prevalence of HTLV-1/2 among patients with malignant hematological diseases. Eighty-eight patients with malignant hematological diseases were tested by enzyme-linked immunosorbent assay (ELISA) for IgG anti-HTLV-1/2 and nested-PCR for the tax gene. The seroprevalence by ELISA was 3.4% and the viral prevalence by nested-PCR tax was 18.2%. HTLV-1 was found in 17% and HTLV-2 in 1% of the patients tested. HTLV-1/2 was found in 17.4% of patients with non-Hodgkin's lymphomas, 28.6% of patients with Hodgkin's lymphomas, 80% of patients with chronic lymphocytic leukemia, 11.4% of patients with acute lymphoblastic leukemia, and 22.2% of patients with acute myeloid leukemia. A high prevalence of HTLV-1/2 was found in patients with malignant hematological diseases. A high proportion of patients were seronegative to HTLV-1/2 infection, similar to other HTLV-1/2 associated disorders. Because 50% of patients positive for HTLV-1/2 were below 30 years old, it is suggested that vertical transmission could have played an important role in these patients.     

Expression of heat-shock protein-90 in non-Hodgkin's lymphomas.

Heat-shock protein-90 (HSP90) inhibitors are currently being used in phase I clinical trials for treating patients with a variety of neoplasms including lymphomas. Using immunohistochemical methods, we assessed for HSP90 expression in 412 cases of non-Hodgkin's lymphoma. In B-cell lymphomas, HSP90 was moderately to strongly expressed in all cases of Burkitt's lymphoma (5/5, 100%), and in subsets of follicular lymphoma (17/28, 61%), diffuse large B-cell lymphoma (27/46, 59%), nodal marginal zone B-cell lymphoma (6/16, 38%), plasma cell neoplasms (14/39, 36%), small lymphocytic lymphoma/chronic lymphocytic leukemia (3/9, 33%), mantle cell lymphoma (12/38, 32%) and lymphoplasmacytic lymphoma/Waldenstrom macroglobulinemia (3/10, 30%). HSP90 was weakly expressed in six of 14 (43%) cases of extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue. In T-cell lymphomas, HSP90 was moderately to strongly expressed in subsets of anaplastic large-cell lymphoma (14/24, 58%; 9/12 ALK+ and 5/12 ALK-), precursor-T-cell lymphoblastic leukemia/lymphoma (20/65, 31%), unspecified peripheral T-cell lymphoma (8/43, 23%) and angioimmunoblastic T-cell lymphoma (2/17, 12%). HSP90 was weakly expressed in seven of 58 (12%) cases of mycosis fungoides. We conclude that HSP90 is commonly expressed in a subset of many types of B- and T-cell lymphoma. These data suggest that many lymphoma types are suitable targets for modulation of HSP90 activity, and that HSP90 inhibitors are a potential investigational therapy for lymphoma patients.     

Monoclonal antibodies reactive in routinely processed tissue sections of malignant lymphoma, with emphasis on T-cell lymphomas

The immunoreactivity of eight monoclonal antibodies was evaluated on 45 routinely processed lymphomas (22 T-cell lymphomas, 11 B-cell lymphomas, and 12 cases of Hodgkin's disease). Two antibodies reactive with leukocyte common (T200) antigens (PD7/26 and 2B11) stained most of the B- and T-cell lymphomas but did not stain the Reed-Sternberg cells and variants in Hodgkin's disease. Two antibodies known to stain B cells (LN-1 and LN-2) reacted with some of the B-cell lymphomas, but LN-2 also reacted with the neoplastic cells in six of 22 T-cell lymphomas and with the Reed-Sternberg variants in eight of 12 cases of Hodgkin's disease. The granulocyte antibody anti-Leu M1 reacted with most cases of Hodgkin's disease but also reacted with two of 11 B-cell non-Hodgkin's lymphomas. An antibody to epithelial membrane antigen (anti-EMA) stained some cases of T-cell lymphoma, B-cell lymphoma, and Hodgkin's disease. Leu 7 was expressed in one T-cell lymphoma and in one case of Hodgkin's disease. A novel antibody reactive with T cells (L60) stained all cases of T-cell lymphoma but also stained some cases of B-cell lymphoma and one case of Hodgkin's disease. We conclude that none of these antibodies, when used alone on routinely fixed paraffin-embedded material, is completely sensitive and specific for T-cell lymphoma, B-cell lymphoma, or Hodgkin's disease. However, a panel of antibodies is useful in distinguishing Hodgkin's disease from non-Hodgkin's lymphoma and in suggesting the B- or T-cell phenotype of non-Hodgkin's lymphomas.     

Host ethnicity influences non-Hodgkin''s lymphoma subtype frequency and Epstein–Barr virus association rate: the experience of a multi-ethnic patient population in Malaysia

AIMS: The pattern of malignant lymphoma is known to vary in different populations. This study aims to elucidate the effect of ethnicity on subtype frequency of non-Hodgkin's lymphoma and EBV association rate. METHODS AND RESULTS: A total of 232 reconfirmed lymphoma cases in Malaysian patients were retrieved from the archives in the Department of Pathology, University Hospital, Kuala Lumpur. There were 24 (10%) Hodgkin's and 208 (90%) non-Hodgkin's lymphomas, 173 of the latter were in adult group (aged > or = 15 years). The ethnic composition were 41 Malays, 107 Chinese, 21 Indians and four none of the above. A male : female ratio of 2.4 : 1 was observed. Complete immunohistochemical studies in 158 cases revealed 36 (23%) T-cell, 121 (76%) B-cell and one (1%) null-cell phenotype. Seventy-five percent of the T-cell lymphomas were peripheral T/NK-cell types. Among the classifiable lesions, low-grade/indolent lymphomas constituted 17%: 2% were the lymphocytic subtype and 10% were follicular lymphomas. Approximately one-third of the follicular lymphomas occurred in Indian patients. The largest group of high-grade lymphoma was diffuse large B-cell type (46%), followed by peripheral T/NK-cell (18%). A predominance of NK/T-cell lymphomas occurred in Chinese (5/7), and all were EBV associated. Burkitt's lymphoma accounted for 5% (eight cases), all were Chinese males, with a 38% EBV-association rate. The frequency of EBV-associated B-cell lymphoma is three times more common in Chinese than Malays. The EBV positivity rate among lymphomas in ethnic Malay, Chinese and Indian patients was 5%, 15% and 22%, respectively, and in T- and B-cell lymphomas was 36% and 7%, respectively. CONCLUSIONS: This Malaysian series reveals differences in the subtype frequencies of non-Hodgkin's lymphomas and EBV association rate amongst patients of various ethnic groups residing in the same environment.     

Analysis of human equilibrative nucleoside transporter 1 (hENT1) protein in non-Hodgkin's lymphoma by immunohistochemistry.

The human equilibrative nucleoside transporter 1 (hENT1) is a member of the equilibrative nucleoside transporter family that mediates cellular entry of gemcitabine, cytarabine, and fludarabine. Deficiency in hENT1 confers resistance to toxicity of these drugs in a variety of model systems. Since some nucleoside analogs have a role in treating patients with non-Hodgkin's lymphoma (NHL), this study was undertaken to assess hENT1 abundance in NHL. A total of 115 cases of NHL of various subtypes and 15 reactive lymph nodes were evaluated for the presence of hENT1 protein using immunohistochemistry applied to frozen tissues. Samples were considered positive when >or=50% of neoplastic cells showed immunostaining. In reactive lymph nodes, hENT1 was confined to the germinal centers, whereas mantle zone B-cells and interfollicular T-cells were negative. In NHL, a relatively high frequency of hENT1 positivity was found in Burkitt lymphoma/leukemia (63%), diffuse large B-cell lymphoma (DLCL; 45%), and follicular lymphoma (40%). In DLCL, 26% of cases were positive for CD10, and CD10-positive DLCL cases were more likely to be hENT1 positive than CD10-negative cases (P=0.025). A lower frequency of hENT1 positivity was found in mantle cell lymphoma (13%) and peripheral T-cell lymphomas (37%). All marginal zone lymphomas (n=5), chronic lymphocytic leukemia small lymphocytic lymphomas (n=10), plasmacytoma (n=3), acute lymphoblastic lymphoma/leukemia, and anaplastic large-cell lymphomas (n=5) were negative. In conclusion, hENT1 was most frequently found in benign and malignant follicular center cells. Prospective studies to assess the value of hENT1 immunostaining in predicting resistance to nucleoside chemotherapy for NHL are warranted.     

Malignant lymphoma in Nebraska and Guangzhou, China: a comparative study

Two hundred thirty-four consecutive cases of malignant lymphoma (192 non-Hodgkin's lymphomas and 42 Hodgkin's disease) from Guangzhou, China, and 589 cases (498 non-Hodgkin's lymphomas and 91 Hodgkin's disease) from the University of Nebraska Lymphoma Registry were examined in a retrospective histopathologic analysis and the results compared to those of the National Cancer Institute (NCI) Working Formulation Summary. Aggressive non-Hodgkin's lymphoma was excessive in Guangzhou (82.3 per cent; P less than 0.001) and Nebraska (80.3 per cent; P less than 0.001) when compared with the NCI data (54.2 per cent). The small noncleaved cell, lymphoblastic, and diffuse mixed-cell subtypes were more frequent in China (15.6 per cent each; P less than 0.001), whereas the small lymphocytic, follicular large cell, and immunoblastic subtypes predominated in Nebraska (8 per cent, 8.4 per cent, and 21.8 per cent, respectively; P less than 0.001). The overall median age of onset for non-Hodgkin's lymphoma was 42.0 years in Guangzhou and 63.5 years in Nebraska. Hodgkin's disease represented 18 per cent of the malignant lymphomas in Guangzhou and 15 per cent in Nebraska. The mixed-cellularity type was most common in Guangzhou (52 per cent; P less than 0.001) and the nodular-sclerosing type in Nebraska (56 per cent; P less than 0.010). The low median age and excess of certain aggressive subtypes of non-Hodgkin's disease in Guangzhou suggest a possible viral etiology, whereas the excess of certain subtypes of non-Hodgkin's lymphoma in Nebraska may be related to intense agricultural activity.     

Malignant lymphomas involving the central nervous system—a morphological and immunohistochemical study of 32 cases

The morphological features of 32 cases of malignant lymphomas involving the central nervous system presenting over a 32 year period were reviewed and the lymphomas redefined using current classifications. Twenty-four cases (75%) of non-Hodgkin's lymphomas were reclassified using the Kiel classification. There were 18 low grade non-Hodgkin's lymphomas (comprising 11 lymphoplasmacytoid, five lymphocytic and two centroblastic-centrocytic) and six high grade tumours (comprising two centroblastic, two immunoblastic, one unclassifiable and one lymphoblastic lymphoma). Cytologically the great majority of non-Hodgkin's lymphomas were B-cell lymphomas. The eight cases (25%) of Hodgkin's disease were classified by the Rye subtype and consisted of three mixed cellularity, two lymphocyte depletion, two lymphocyte predominant and one nodular sclerosis. The presence of intracytoplasmic immunoglobulins as well as markers for histiocytic cells were studied by the immunoperoxidase technique using polyclonal antisera. A monoclonal staining pattern, as revealed by light chain restriction, was found in nine cases (38%) of the non-Hodgkin's lymphomas confirming their B-cell origin. With the Marshall's metalophil method and the other histiocytic markers, scattered reactive microglial cells and histiocytic reticulum cells were found throughout the tumours in most cases. No histiocytic lymphomas were present in the series.     

Pathologic and immunologic characterization of malignant lymphoma in Taiwan. With special reference to retrovirus-associated adult T-cell lymphoma/leukemia

One hundred four cases of malignant lymphomas, including 90 cases of non-Hodgkin's lymphoma, 5 cases of histiocytic malignancy, and 9 cases of Hodgkin's disease were analyzed pathologically and immunologically using a panel of monoclonal and conventional antibodies for T-, B-, histiocyte, and Hodgkin's neoplastic cells. Our results revealed a high frequency of T-cell lymphoma (42.3%), a low percentage of follicular lymphoma (10.5%), and Hodgkin's disease (8.7%) in Taiwan. More than half of the malignant lymphomas belonged to the high-risk unfavorable group. Peripheral T-cell lymphomas (33 cases) showed characteristic clinical and histologic features, which can sometimes be confused with Hodgkin's disease. Monoclonal antibodies Leu-M1 and 2H9 were an important aid for their differential diagnosis. Five of the 33 peripheral T-cell lymphomas were positive for antibody to adult T-cell lymphoma/leukemia (ATL) virus associated antigen (ATLA). Four patients were from the northeast coast of Taiwan, I-Lan county. Five (4.8%) were diagnosed as true histiocytic malignancies, including two true histiocytic lymphoma and three malignant histiocytosis. Two cases each of large cell lymphoma and immunoblastic lymphoma showed no identifiable marker expression. The distribution of lymphoproliferative disorders in Taiwan is similar to that in Japan but much different from western countries.     

Malignant lymphomas in Korea

A retrospective histological study of 540 malignant lymphomas diagnosed at the Department of Pathology of the Seoul National University from 1976 through 1986 is presented. Malignant lymphoma is the 10th most common malignant tumor in Korea, comprising 3.07% of all malignancy during period of study. Among malignant lymphomas non-Hodgkin's lymphoma accounted for 82% and accordingly the Hodgkin's disease was for 18%. The most common type of non-Hodgkin's lymphoma was diffuse histiocytic lymphoma of Rappaport. Follicular lymphoma was very rare, comprising only 2.3%. T-cell lymphoma accounted for 9.6% of non-Hodgkin's lymphomas, the most frequent type being lymphoblastic lymphoma. Immunoblastic sarcoma and mycosis fungoides were occasionally seen but there was no case of pleomorphic adult T-cell lymphoma. Among Hodgkin's diseases, mixed cellularity type was the most common type, and nodular sclerosis type was relatively rare.     

Pattern of Epstein-Barr virus association in childhood non-Hodgkin's lymphoma: experience of university of malaya medical center

The pattern of childhood non-Hodgkin's lymphoma (NHL) usually differs in adults. The most common subtypes are lymphoblastic, Burkitt's and anaplastic large cell lymphoma. Recent data indicate that a higher risk of developing lymphoma is associated in children of certain ethnic origins. The difference is probably related to the underlying etiological factors of these diseases, and Epstein-Barr virus (EBV) is a strong candidate. The present study aims to determine the disease pattern of childhood lymphomas in the University Hospital Kuala Lumpur, for a direct comparison to the reported data of adults from the same medical center. A total of 69 and 34 childhood NHL and Hodgkin's lymphomas, respectively, were retrieved. The most common subtypes were lymphoblastic (23 cases), Burkitt's (25 cases) and anaplastic large cell lymphomas (9 cases). Epstein-Barr virus association was more prevalent in B-cell (23%) than T-cell (12%) lymphomas. The most common EBV-associated tumor was Burkitt's lymphoma, and there was an increased risk of EBV association for Burkitt's lymphoma in Chinese patients. In conclusion, the pattern of childhood lymphoma in Malaysia is relatively similar to children elsewhere in the world. The EBV association of B- and T-NHL differs between children and adults from the same medical center because of differences in the subtype composition in these two age groups.     

Heterogeneity of protein kinase C beta(2) expression in lymphoid malignancies

AIMS: Protein kinase C (PKC) beta is an important regulator of lymphoid survival and its expression has been shown to be altered in lymphomas. The aim was to determine the expression of PKC beta(2) in various subtypes of lymphoproliferative diseases by immunohistochemistry. METHODS AND RESULTS: One hundred and forty archival samples representing various subtypes of lymphoproliferative diseases were analysed. Certain subtypes, such as mantle cell, lymphocytic or follicular lymphoma, were found to express PKC beta(2) in > 90% of the samples. In follicular lymphomas, the follicular lymphomatous areas were constantly labelled, whereas residual germinal centres remained negative. In follicular hyperplasia, PKC beta(2)+ cells were found in the mantle and marginal zones. Most angioimmunoblastic T-cell lymphomas, lymphoblastic T-cell lymphomas and marginal zone/mucosa-associated lymphoid tissue (MALT) lymphomas were labelled with anti-PKC betaII antibody, but the pattern of expression was more heterogeneous in these subtypes. A minority of diffuse large B-cell lymphomas were stained and most plasma cell malignancies were negative. None of the cases of Hodgkin's disease and anaplastic large cell lymphoma expressed PKC beta(2). CONCLUSIONS: PKC beta(2) expression varies significantly among lymphoproliferative diseases. In our series, the highest level of expression was found in mantle cell lymphomas and chronic lymphocytic lymphoma.     

Histological and immunohistochemical studies on primary gastrointestinal lymphomas.

To study the characteristics and histogenesis of the malignant lymphomas derived from the gastrointestinal mucosa, histologic and immunohistochemical analyses were performed on a series of 28 malignant lymphomas of the gastrointestinal tract. By cytomorphologic classification, there were two small lymphocytic lymphomas, one small cleaved cell lymphoma, two mixed small cleaved and large cell lymphomas, 17 large cell lymphomas, one small noncleaved cell lymphoma, three immunoblastic lymphomas, and two lymphoblastic lymphomas. This distribution of histologic types was compatible with that of nodal lymphoma. The lymphomas with poor prognostic histology (23 cases) outnumbered those with favorable prognosis (five cases). Three of 28 cases (one in the stomach and two in the small intestine) had cytologic features consistent with centrocytoid cell lymphoma of the mucosa associated lymphoid tissue and were large cell lymphomas. Immunophenotypically, 23 cases expressed B-cell markers (82.1%) and three cases reacted with T-cell markers. Two cases did not react with either T-cell or B-cell markers. True histiocytic lymphomas were not identified. Gastric lymphomas (nine cases) and colorectal lymphomas (three cases) were of B-lymphocyte origin whereas T-cell lymphomas were noted in the small intestine (two cases) and ileocecal region (one case). Three cases of centrocytoid lymphoma were of B-lymphocyte origin. Histologically B-cell lineage lymphomas were evenly distributed on various histologic subtypes but all T-lineage lymphomas belonged to the large cell type. The two cases with undetermined phenotype were lymphoblastic lymphomas histologically. This study showed that the primary GIT lymphomas, mostly of B-cell lineage, were not cytomorphologically distinctive from the nodal lymphomas.(ABSTRACT TRUNCATED AT 250 WORDS)