Search

The revised fourth edition of the World Health Organization (WHO) Classification of Tumours of Haematopoietic and Lymphoid Tissues (2017) reflects significant advances in understanding the biology, genetic basis and behaviour of haematopoietic neoplasms. This review focuses on some of the major changes in B-cell and T-cell non-Hodgkin lymphomas in the 2017 WHO and includes more recent updates. The 2017 WHO saw a shift towards conservatism in the classification of precursor lesions of small B-cell lymphomas such as monoclonal B-cell lymphocytosis, in situ follicular and in situ mantle cell neoplasms. With more widespread use of next generation sequencing (NGS), special entities within follicular lymphoma and mantle cell lymphoma were recognised with recurrent genetic aberrations and unique clinicopathological features. The diagnostic workup of lymphoplasmacytic lymphoma and hairy cell leukaemia has been refined with the discovery of MYD88 L265P and BRAF V600E mutations, respectively, in these entities. Recommendations in the immunohistochemical evaluation of diffuse large B-cell lymphoma include determining cell of origin and expression of MYC and BCL2, so called 'double-expressor' phenotype. EBV-positive large B-cell lymphoma of the elderly has been renamed to recognise its occurrence amongst a wider age group. EBV-positive mucocutaneous ulcer is a newly recognised entity with indolent clinical behaviour that occurs in the setting of immunosuppression. Two lymphomas with recurrent genetic aberrations are newly included provisional entities: Burkitt-like lymphoma with 11q aberration and large B-cell lymphoma with IRF4 rearrangement. Aggressive B-cell lymphomas with MYC, BCL2 and/or BCL6 rearrangements, so called 'double-hit/triple-hit' lymphomas are now a distinct entity. Much progress has been made in understanding intestinal T-cell lymphomas. Enteropathy-associated T-cell lymphoma, type II, is now known to not be associated with coeliac disease and is hence renamed monomorphic epitheliotropic T-cell lymphoma. An indolent clonal T-cell lymphoproliferative disorder of the GI tract is a newly included provisional entity. Angioimmunoblastic T-cell lymphoma and nodal T-cell lymphomas with T-follicular helper phenotype are included in a single broad category, emphasising their shared genetic and phenotypic features. Anaplastic large cell lymphoma, ALK- is upgraded to a definitive entity with subsets carrying recurrent rearrangements in DUSP22 or TP63. Breast implant-associated anaplastic large cell lymphoma is a new provisional entity with indolent behaviour. Finally, cutaneous T-cell proliferations include a new provisional entity, primary cutaneous acral CD8-positive T-cell lymphoma, and reclassification of primary small/medium CD4-positive T-cell lymphoma as lymphoproliferative disorder., (Copyright © 2021 Royal College of Pathologists of Australasia. Published by Elsevier B.V. All rights reserved.)

Non-Hodgkin lymphomas (NHLs) are a diverse group of entities, both clinically and molecularly. Here, we review the evolution of classification schemes in B-cell lymphoma, noting the now standard WHO classification system that is based on immune cell-of-origin and molecular phenotypes. We review how lymphomas arise throughout the B-cell development process as well as the molecular and clinical features of prominent B-cell lymphomas. We provide an overview of the major progress that has occurred over the past decade in terms of our molecular understanding of these diseases. We discuss treatment options available and focus on a number of the diverse research tools that have been employed to improve our understanding of these diseases. We discuss the problem of heterogeneity in lymphomas and anticipate that the near future will bring significant advances that provide a measurable impact on NHL outcomes., (Copyright © 2021 Cold Spring Harbor Laboratory Press; all rights reserved.)

Background & Objectives: The PAX5, a paired box transcription factor and B-cell activator protein (BSAP), activates B-cell commitment genes and represses non-B-cell lineage genes. About 14 transcript variants of PAX5 have been observed in human. Any alteration in its expression pattern leads to lymphogenesis or associated diseases and carcinogenesis in non-lymphoid tissues. Its mechanisms of function in pathophysiology of non-Hodgkin's lymphoma (NHL) are unclear. This study was intended to explore influence of PAX5 in cascade of NHL pathogenesis and diagnosis., Methods: Samples of 65 patients were evaluated by immunohistochemical staining for cellular localization of PAX5, CD19, CD3, cABL, p53, Ras and Raf and by TUNEL assay, RNA-isolation and reverse transcriptase (RT)-PCR, w0 estern blot analysis, and lactate dehydrogenase (LDH) specific staining., Results: B-cell type NHL patients were positive for PAX5, p53, Ras, CD19, Raf and CD3. All of them showed TUNEL-positive cells. The differential expression pattern of PAX5, CD19, p53, CD3, Zap700 , HIF 1α, Ras, Raf and MAPK (mitogen-activated protein kinase) at the levels of transcripts and proteins was observed. The LDH assay showed modulation of LDH4 and LDH5 isoforms in the lymph nodes of NHL patients., Interpretation & Conclusions: The histological observations suggested that the patients represent diverse cases of NHL like mature B-cell type, mature T-cell type and high grade diffuse B-cell type NHL. The findings indicate that patients with NHL may also be analyzed for status of PAX5, CD19 and ZAP70, and their transcriptional and post-translational variants for the differential diagnosis of NHL and therapy., Competing Interests: None.

Non-Hodgkin's lymphoma comprises many related but distinct diseases and diagnosis and classification is complex. Protein profiling of lymphoma biopsies may be of potential value for use in this lymphoma classification and the discovery of novel markers. In this study, we have optimized a method for SELDI-TOF MS based protein profiling of frozen tissue sections, without dissection of tumour cells. First we have compared chip surfaces and lysis buffers. Also, we have determined the minimal input using laser dissection microscopy. Subsequently, we have analyzed and compared protein profiles of diffuse large B-cell lymphoma (n=8), follicular lymphoma (n=8) and mantle cell lymphoma (n=8). Benign, reactive lymph nodes (n=14) were used as a reference group.CM10 chip surface in combination with urea lysis buffer and an input of approximately 50,000 lymphocytes allowed the detection of many differential peaks. Identification of the diffuse large B-cell lymphoma cases was reliably made in the supervised classification. Unsupervised clustering showed segregation into a benign/indolent cluster predominantly formed by benign, reactive lymph nodes and follicular lymphoma cases and into a more aggressive cluster formed by diffuse large B-cell lymphoma and mantle cell lymphoma cases. In conclusion, our protocol enables protein profiling of protein lysates derived from small histological samples and the subsequent detection of many differentially expressed proteins, without the need of tumour cell dissection. These results support further evaluation of protein profiling of small lymphoma biopsies as an additional tool in pathology.

Non-Hodgkin lymphomas (NHLs) are often present outside the lymph nodes. Although primary extranodal NHLs (PE-NHL) form a substantial part of all NHLs, reports on oral PE-NHLs are rare. Forty patients with PE-NHL of the oral cavity have been studied for the distribution of gender, age, oral subsite and presenting complaint, histological subtype according to the WHO classification, clinical stage, treatment, and follow-up. The data are reviewed against the background of the literature. Furthermore, the International Prognostic Index has been taken into consideration. All patients had a lymphoma of B-cell lineage. Two-thirds of patients presented with locoregional disease. Mean survival time was 38 months, with a mean recurrence-free survival time of 31 months. There was no statistically significant difference in survival time between patients with bone versus soft tissue localisation of the PE-NHL. In view of the rarity of PE-NHL involving the oral region multicenter studies are needed for evaluation of the usefulness of the International Prognostic Index for non-Hodgkin lymphoma in this particular part of the body.

Purpose: To analyze the influence of radiotherapy doses, chemotherapy doses, and clinical parameters on in-field disease control to assess the optimal radiation doses for treatment of non-Hodgkin's lymphoma according to the newly proposed WHO classification., Patients and Methods: Subjects consisted of 35 extranodal marginal-zone B-cell lymphomas of mucosa-associated lymphoid tissue (MALT) type, 75 diffuse large B-cell lymphomas (DLBCL), 14 follicular lymphomas, 17 extranodal natural killer (NK)/T-cell lymphomas, nasal type, eight unclassified peripheral T-cell lymphomas, four anaplastic large-cell lymphomas, T/null cell type, and five others. 59 patients received radiotherapy alone. 98 patients received CHOP, modified CHOP, or more intensive chemotherapy, and six patients were treated with other combination., Results: No patients with MALT lymphoma had in-field local recurrence. There were no recurrences in DLBCL patients who received chemotherapy in which the doses of adriamycin were > 200 mg/m(2), nor in DLBCL patients who were treated with > 45 Gy. Only nine of 15 patients with T-cell lymphoma treated with < or = 50 Gy and three of five patients treated with > 50 Gy had local control. The dose of adriamycin had no influence on local control of T-cell lymphoma., Conclusion: T/NK-cell lymphomas were more radioresistant than B-cell lymphomas. The prognosis for peripheral T/NK-cell lymphomas is poor even when treated by irradiation combined with chemotherapy.

Objective: To describe the relative frequency, morphologic features, immunophenotype and clinical data of different types of B-cell non-Hodgkin lymphoma (B-NHL) and to evaluate the practical application of the 2001 World Health Organization (WHO) classification of lymphoid neoplasms., Methods: 369 documented cases of B-NHL were further subtyped according to the 2001 WHO classification of lymphoid neoplasms, on the basis of hematoxylin and eosin staining, immunohistochemistry and in-situ hybridization techniques., Results: Amongst the 369 cases of B-NHL studied, 353 cases could be further classified into 11 subtypes. Diffuse large B-cell lymphoma, extranodal marginal zone lymphoma and follicular lymphoma were the commonest subtypes, accounting for 51.2% (189 cases), 14.9% (55 cases) and 10.6% (39 cases) of all cases respectively. Tumors in lymph nodes were seen in 158 cases (42.8%) and in extra node in 211 cases (57.2%). B-cell prolymphocytic leukemia and hairy cell leukemia were not identified. When comparing the diagnosis based on morphologic examination alone with the diagnosis based on both morphology and immunophenotype, there was a 80% concordance rate. Immunohistochemical study was helpful in reaching the correct diagnosis in many cases and could improve the overall diagnostic accuracy by about 20%., Conclusions: Amongst cases of B-NHL, diffuse large B-cell lymphoma is the commonest subtype, followed by MALToma and follicular lymphoma. While morphologic examination forms the basis for lymphoma diagnosis, immunohistochemical study also plays an important role in further subtyping. A combination of both modalities are sufficient for arriving at an accurate diagnosis in most cases of B-NHL, in keeping with the recommendation of the 2001 WHO classification of lymphoid neoplasms.

The classification of lymphomas has been one of the most controversial areas of tumour pathology. Most of the difficulties in development of sophisticated classifications have been a direct consequence of the biological diversity inherent in this group of neoplasms; a reflection of the physiological complexity of lymphocyte development and differentiation. The new World Health Organisation (WHO) lymphoma classification identifies individual clinicopathological entities; integrating morphology, immunophenotype, genotype, normal cell counterpart/cell of origin and clinical features. The degree to which these five characteristics contributes to the definition of individual entities differs from one entity to the other. This classification has received worldwide acceptance in the short term it has been available and has become the gold standard in lymphoma diagnosis.

We retrospectively reviewed 74 fine-needle aspiration (FNA) cases of presumptive non-Hodgkin lymphoma (NHL). All the cases had cytology and core-needle biopsy and 53 cases had concurrent flow cytometric analysis. FNA (cytology and flow cytometry) and core-needle biopsy were evaluated independently. FNA was diagnostic of diffuse large B-cell lymphoma (DLBL) in 25% (13/53) of cases and small B-cell NHL in 15% (8/53) of cases, whereas core-needle biopsy was diagnostic of DLBL in 37% (27/74) of cases and small B-cell NHL in 8% (6/74) of cases. Subclassification of small B-cell NHL was reached in 3/6 cases by core-needle biopsy. Insufficient cases were observed in both FNA (47%; 25/53) and core-needle biopsy (28%; 21/74) groups. With the combination of FNA and core-needle biopsy, diagnostic cases of DLBL increased to 43% (32/74) and insufficient samples were reduced to 16% (12/74). There was no clear advantage in the diagnosis and classification of small B-cell NHL by adding core-needle biopsy to FNA (14%; 10/74). We conclude that core-needle biopsy is a useful adjunct to FNA in the diagnosis of DLBL and shall be encouraged. In small B-cell NHL, core-needle biopsy does not add to the diagnostic ability of FNA. Cases insufficient for diagnosis may be seen in both core-needle biopsy and FNA. A combined approach reduces the number of insufficient cases and is recommended in routine FNA practice., (Copyright 2004 Wiley-Liss, Inc.)

B-cell lymphomas comprise up to 25% of primary cutaneous non-Hodgkin lymphoma (NHL). Two main classification systems are used, namely the European Organization for Research and Treatment of Cancer (EORTC) and the World Health Organization (WHO) classification of tumours. Indeed, there is much controversy surrounding which classification system to use, which in turn influences the interpretation of existing data and subsequently how we manage patients with these conditions.

The development of the WHO classification of lymphoid neoplasms is a remarkable example of cooperation and communication between pathologists and oncologists from around the world. Joint classification committees of the major hematopathology societies will periodically review and update this classification, facilitating further progress in the understanding and treatment of hematologic malignancies.

Several lines of evidences suggest that T cell/histiocyte-rich B-cell lymphoma (T/HRBCL) represents an aggressive variant of the clinically indolent entity nodular lymphocyte predominance Hodgkin's lymphoma (LPHL). Still, this view has not yet been supported by firm genetic evidence. In this study, we analyzed 17 T/HRBCL cases using comparative genomic hybridization (CGH) combined with microdissection of single CD20+ neoplastic cells and DNA amplification by degenerate oligonucleotide primed-polymerase chain reaction, an approach we previously used in LPHL. Genomic imbalances were detected in all cases (in total, 80 changes). The most common imbalances included gain of Xq, 4q13q28, Xp21p11, and 18q21, and loss of 17p. Of note, a partial gain of 4q, a rare change in lymphoma, is also among the genomic imbalances most frequently encountered in LPHL. On the other hand, the CGH profiles of T/HRBCL and LPHL showed several distinct features, in particular with respect to the number of genomic imbalances (average of 4.7 in T/HRBCL versus 10.8 in LPHL) and their distribution (usually 1 to 5 in T/HRBCL versus 6 to 22 in LPHL). Altogether, our CGH findings of shared as well as distinctive cytogenetic features in both diseases suggest that T/HRBCL constitutes a separate lymphoma entity, possibly originating from the same precursor cell as LPHL.

Objective: To review the current literature on HIV associated non-Hodgkin's lymphoma., Methods: A comprehensive Medline/Pubmed search of articles pertaining to HIV associated non-Hodgkin's lymphoma as well as personal experience from the treatment of over 200 patients at the Chelsea and Westminster Hospital, one of the largest centres for the management of HIV disease in Europe., Conclusion: High grade B cell non-Hogdkin's lymphoma is the second commonest tumour affecting people with HIV. The incidence of this tumour is not declining following the introduction of highly active antiretroviral therapy. Chemotherapy has been employed with modest success in this group of patients; however, the prognosis remains worse than for immunocompetent patients. Advances in molecular genetics and virology have led to a greater understanding of the biology of these tumours. However, these advances have yet to be translated into improvements in the clinical management of patients with AIDS associated non-Hodgkin's lymphoma.

New insights into the immunology and genetics of malignant lymphomas have allowed the recognition of new entities and the refinement of previously recognized disease categories. The relative incidence of these subtypes of malignant lymphoma is also known to differ according to geographic location. In order to clarify the current status of malignant lymphomas in Japan and the relative incidences of their subtypes, 3194 patients were classified according to the new World Health Organization (WHO) classification. Among these were 3025 cases (94.71%) of non-Hodgkin's lymphoma (2189 cases (68.53%) of B-cell lymphoma, 796 cases (24.92%) of T-cell lymphoma) and 141 cases (4.41%) of Hodgkin's lymphoma. The incidences of the major subtypes of non-Hodgkin's lymphoma were 33.34% for diffuse large B-cell lymphoma, 8.45% for marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) type, 8.05% for plasma cell myeloma, 7.45% for adult T-cell leukemia/lymphoma (ATLL), 6.7% for follicular lymphoma, 6.67% for peripheral T-cell lymphoma of unspecified type, 2.79% for mantle cell lymphoma, 2.6% for nasal and nasal-type T/NK cell lymphoma, 2.35% for angioimmunoblastic T-cell lymphoma, and 2.35% for precursor B-cell lymphoblastic leukemia/lymphoma, in decreasing order. The other subtypes comprised less than 2%, mainly precursor T-cell lymphoblastic lymphoma/leukemia (1.72%), anaplastic large-cell lymphoma of T- and null-cell types (1.53%), and B-cell chronic lymphocytic leukemia/small lymphocytic lymphoma (1.31%). The incidence of ATLL was influenced by its high percentage (19.20%) in the south-western Japanese island, Kyushu, an endemic area of human T-cell leukemia virus type 1 (HTLV-1), but which appeared to be lower than that in a previous study. The nodular sclerosis and mixed cellularity types of Hodgkin's disease occupied 1.78% and 1.63%, respectively. These data are distinct from those in Western countries and similar in several ways to those in the East, although the relatively high rate of ATLL was attributed to the geographical difference in the etiologic factor, HTLV-1.

Recently great advances were achieved in the recognition and classification of primary cutaneous lymphomas. With this increased knowledge, one must realize that we must deal with new concepts that are sometimes confusing and controversial. The following controversial subjects are presented in this article: (1) Classification of cutaneous lymphomas; (2) Cutaneous T-cell lymphoma with small/medium-sized pleomorphic cells as a distinct entity; (3) Primary cutaneous follicle center lymphoma and marginal zone lymphoma/ immunocytoma.

In the last decade many studies showed that primary cutaneous lymphomas have another clinical behavior and prognosis, and therefore require a different therapeutic approach, as compared with their primary nodal equivalents. Because, until recently, classification systems for non-Hodgkin's lymphomas were purely based on histologic criteria, and did not recognize the special character of these lymphomas, primary cutaneous lymphomas were not uncommonly diagnosed incorrectly and/or treated inappropriately with unnecessarily aggressive therapies. For that reason the Cutaneous Lymphoma Group of the European Organization for Research and Treatment of Cancer (EORTC) proposed a separate classification for the group of primary cutaneous lymphomas. This EORTC classification is consistently based on a combination of clinical, histologic, immunophenotypical and genetic criteria, and includes well-defined and recognizable disease entities. It contains a limited number of cutaneous T-cell lymphomas and cutaneous B-cell lymphomas, which together constitute more than 95% of all primary cutaneous lymphomas. Herein, the rationale and the basic principles of the EORTC classification are presented, and the relationship between the EORTC classification and other recent classification systems, such as the Revised European-American Classification for Lymphoid Neoplasms (REAL classification) and the proposed World Health Organization classification, are discussed.

Background: The Revised European-American Lymphoma (R.E.A.L.) Classification criteria were evaluated in the international protocol FAB LMB 96 Treatment of Mature B-cell Lymphoma/Leukemia: A SFOP LMB 96/CCG-5961/UKCCSG NHL 9600 Cooperative Study. This includes B-lineage lymphomas: Burkitt's lymphoma (including ALL-L3); high-grade B-cell lymphoma, Burkitt-like; diffuse large B-cell lymphoma (excluding anaplastic large cell Ki-1 lymphoma)., Patients and Methods: Cases were independently reviewed by eight hematopathologists from the three cooperative national groups (two SFOP, two CCG, four UKCCSG), without prior discussion of classification criteria or guidelines for case rejection. Consensus diagnosis was determined by each national cooperative group, and final consensus diagnosis established when at least two national consensus diagnoses were in agreement, or following group agreement at a multiheaded microscope., Results: Two hundred eight cases were reviewed, with final consensus diagnosis established in two hundred three. The percent agreement of each group's national consensus diagnosis with final consensus diagnosis was 86%, 86% and 71%. The percent agreement of the group's national consensus diagnosis with final consensus diagnosis for Burkitt's and diffuse large B-cell lymphoma were 88% and 80%, respectively, but only 42% for Burkitt-like lymphoma., Conclusions: International panel review of mature B-cell lymphoma/leukemia in children and adolescents highlighted difficulties in subclassification, particularly with Burkitt-like, which is a 'provisional entity' in the R.E.A.L. Classification. The absence of previous discussion of classification and guidelines for case rejection may in part explain the discrepancy between pathologists. These results underline that morphology may need to be complemented by other studies, such as molecular genetic and cytogenetics, to discriminate between the mature B-cell lymphomas.

In the REAL classification the diffuse large B-cell non-Hodgkin lymphomas (NHL) are grouped together, because subclassifications are considered to lack both reproducibility and clinical significance. Others, however, claim that patients with an immunoblastic NHL have a worse prognosis than patients with other types of diffuse large B-cell NHL. Therefore, we investigated the prognostic and clinical significance of histological subclassification of diffuse large B-cell NHL in a uniformly treated series of patients. For this retrospective study, all patients diagnosed as having an immunoblastic (IB) B-cell NHL by the Lymphoma Review Panel of the Comprehensive Cancer Center Amsterdam (CCCA) between 1984 and 1994, and treated according to the guidelines of the CCCA, were analysed. Patients with a centroblastic polymorphic subtype (CB-Poly) or centroblastic (CB) NHL by the Lymphoma Review Panel who were treated in the Netherlands Cancer Institute during the same period according to CCCA guidelines were used as reference groups. All patients' records were reviewed. Clinical parameters at presentation, kind of therapy and clinical outcome were recorded. All available histological slides were separately reviewed by two haemato-pathologists. One hundred and seventy-seven patients were included in the study: 36 patients (20.3%) with an IB NHL, 69 patients (39%) with a CB-Poly NHL and 72 patients (40.7%) with a CB NHL. The patients with an IB NHL tended to be older and presented more often with stage I or II and one extranodal site than patients with a CB and CB-Poly NHL. None of the subtypes showed a clear preference for localization in a particular site. The patients with IB or CB-Poly NHL showed a significantly worse prognosis than patients with CB NHL, with a 5-year overall survival for patients with CB NHL of 56.3% and for patients with IB or CB-Poly NHL 39.1% and 41.6% respectively. The 5-year disease free survival was 53.2% for the patients with CB, 32% for the patients with CB-Poly and 26.9% for the patients with IB NHL. A multivariate analysis showed that histological subtyping was of prognostic significance independent of the International Prognostic Index. This finding merits further exploration in prospective studies in order to judge the value of subclassification of large B-cell NHL as a guideline in therapy choice.

Background and Objective: Molecular genetic abnormalities have been frequently described in non-Hodgkin's lymphomas (NHL). These lesions have been associated with specific entities, allowing a better categorization of NHL. However, these abnormalities are not as specific as initially described and their association is still unknown., Design and Methods: By Southern blot and polymerase chain reaction, we have simultaneously analyzed the proto-oncogenes Bcl-1, Bcl-2, Bcl-6, c-myc and MLL and the tumor suppressor genes p53 and p16, in 100 unselected B-cell NHL patients at diagnosis, to establish its incidence throughout the different NHL subtypes, defined both by Working Formulation and REAL classifications, and to assess the frequency of co-existence of two or more genetic lesions within each individual patient., Results: Fifty two cases displayed some genetic abnormality. Bcl-1, altered in 12 cases, was highly specific to mantle cell lymphomas (57% of them), but 6 cases had a different histologic subtype. Bcl-2 was rearranged in 26 cases: 70% in follicular lymphomas (FL) and 20% in diffuse large cell lymphomas; these abnormalities were also present in other subtypes, i.e. marginal lymphomas (30%). Bcl-6 abnormalities were mostly found in diffuse large cell lymphomas (29%) but also found in other subgroups, like FL (14%). C-myc rearrangements were specific to Burkitt's lymphoma. MLL gene was always germline. Deletions and/or rearrangements of p53 and p16 genes were rare (4% and 8% of all cases, respectively). Finally, association of genetic lesions was a relatively common finding (13% of cases), especially in cases with adverse prognostic morphologies according to the REAL., Interpretation and Conclusions: Molecular abnormalities are frequent in NHL at diagnosis, not only as unique lesions but also associated. A relative high specificity of some alterations was seen, thereby contributing to a better assessment of the histological subtype.

Subclassification of malignant non-Hodgkin's lymphoma is important to be able to choose the right treatment. However, this subclassification can be difficult, and immunohistochemistry and polymerase chain reaction are used to improve diagnostic safety. We have investigated the value of immunohistochemistry and polymerase chain reaction in the subclassification of 49 low grade non-Hodgkin's lymphomas of B-cell type. Immunohistochemistry showed B-cell phenotype in all biopsies, and 23 (85%) of 27 follicular lymphomas showed positive reaction for bcl-2 antibodies in follicles. Polymerase chain reaction demonstrated a monoclonal pattern for IgH in 36 (73%) of 49 biopsies, and 10 (37%) of 27 follicular lymphomas demonstrated translocation (14; 18). Immunohistochemistry and polymerase chain reaction contributed to subclassification or confirmation of the diagnosis of 46 (94%) of 49 biopsies. Our conclusion is that immunohistochemistry and polymerase chain reaction have a natural place in the diagnosis of lymphomas.

CD5 is useful for the classification of low-grade B-cell lymphomas, because it is aberrantly expressed in B-cell chronic lymphocytic leukemias/small lymphocytic lymphomas (B-CLLs/SLLs) and mantle cell lymphomas (MCLs), but not in the other well-described low-grade B-cell lymphomas. Therefore, we tested the utility of monoclonal antibody (MAb) 4C7 to detect CD5 on paraffin sections of 22 cases with low-grade B-cell lymphomas and 4 cases with high-grade B-cell lymphomas and compared the results with CD5 detection by analysis of fresh tissue with a fluorescent-activated cell sorting (FACS). After heat-induced epitope retrieval we could detect CD5 on paraffin sections in all MCLs and B-CLLs/SLLs, identical to the results of flow cytometry. Eleven of 12 cases that showed no CD5 expression by FACS analysis were also negative on paraffin sections. In only one case of a presumed blastoid MCL, CD5 was detectable by immunohistochemistry but not by FACS analysis. We conclude that MAb 4C7 against CD5 is a useful paraffin-reactive marker, especially to correctly identify MCLs on paraffin sections.

A prospective analysis of 38 cases of bovine lymphoma was performed. Thirty-five of the lymphomas were considered enzootic because of serologic or molecular biologic association with the bovine leukemia virus (BLV). The three remaining cases were in cattle < 1 year of age and were not associated with BLV and hence were considered sporadic lymphomas. Utilizing the national cancer Institute Working Formulation for the morphologic classification of human non-Hodgkin's lymphoma, 54.3% (19/35) of the enzootic lymphomas were classified as the diffuse large cleaved cell type. The cells of the 35 enzootic lymphomas expressed a consistent immunophenotype represented by MHCII+, gamma-heavy chain+, and lambda-light chain+; this constellation of markers indicated a mature B-cell phenotype. The three sporadic lymphomas failed to express MHCII antigen despite the presence of other B-cell antigens. There was no correlation between morphologic cell type and immunophenotype in these bovine lymphomas.

We report here a large series of B-cell neoplasms with regard to rearrangement of the BCL6 gene on chromosome band 3q27. Southern blot analysis using probes from the major translocation cluster (MTC) region of the BCL6 revealed rearrangement in 32 of a total of 222 patients with various subtypes of B-cell neoplasm. In non-Hodgkin's lymphoma (NHL), rearrangements of the BCL6 gene were not closely associated with a specific histopathologic subtype but distributed in subcategories in the Working Formulation. A comparative study between NHL associated either with BCL2 or BCL6 rearrangement showed that advanced disease and bone marrow involvement were more frequent in BCL2(+) NHL. In contrast, extranodal involvement was more frequently observed in the BCL6(+) NHL. The survival curve of BCL6(+) NHL was characterized by a rapid decline followed by a plateau. Of the total of 32 BCL6(+) patients, 6 carried both BCL2 and BCL6 rearrangements, and showed clinicopathological properties of follicular lymphoma. This study suggests that BCL6 rearrangement is primarily associated with large cell lymphoma, and that BCL2(-)BCL6(+) NHL could potentially be curable with modern combination chemotherapy.

Objectives: Epstein-Barr virus is periodically shed in the saliva of persons infected by the virus. Epstein-Barr virus has been implicated in the pathogenesis of certain subtypes of lymphoma, particularly high-grade lymphomas. Because high-grade subtypes represent the majority of lymphomas that arise in oral soft tissues, we hypothesized that Epstein-Barr virus might be preferentially associated with oral lymphomas., Study Design: A series of 34 oral lymphomas were diagnosed according to the revised European-American classification scheme. They were examined for the presence of latent Epstein-Barr virus by EBER1 in situ hybridization and for expression of the Epstein-Barr virus replicative protein, BZLF1, by immunohistochemistry., Results: Epstein-Barr virus EBER1 transcripts were detected in 11 of 31 oral lymphomas including 7 of 10 AIDS-related lymphomas and only 4 of 21 lymphomas that occurred in nonimmunocompromised persons. The Epstein-Barr virus-containing lymphomas were all high-grade histologic subtypes, that is, diffuse large cell, immunoblastic, or Burkitt's lymphomas. In contrast, Epstein-Barr virus was not detected in any of five low-grade oral lymphomas. In the single case of T-cell lymphoma in this study, EBER1 was expressed in the tumor cells. A switch from viral latency to replication, as measured by EBV BZLF1 expression, was identified in rare lymphoma cells in only four cases. This rate of viral replication was not higher than what has been reported in lymphomas arising at other anatomic sites. Although one of our lymphomas arose at a site of previous oral hairy leukoplakia, there was no other evidence that Epstein-Barr virus replication predisposed to development or persistence of oral lymphomas., Conclusions: These data suggest that even though Epstein-Barr virus is frequently found in oral secretions, neither latent nor replicative Epstein-Barr virus is present more commonly in oral lymphomas than in lymphomas arising in other anatomic sites, when controlling for immunodeficiency status.

To elucidate the relationship between the clinical features and pathologic findings of primary pulmonary lymphoma, we reviewed 24 patients with this disease. The pulmonary lymphomas were divided into four groups: (1) B-cell lymphoma composed of small to medium-sized lymphoid cells (19 cases); (2) B-cell lymphoma composed of large lymphoid cells (three cases); (3) T-cell lymphoma (one case); (4) malignant lymphoma of lymphomatoid granulomatosis (LYG) type (one case). Radiographs of the first group revealed a predominance of infiltration associated with ill-defined tumor margins upon gross pathology, corresponding histologically to lymphangitic spread. Air bronchogram and pleural tail or abutment were additional radiographic features. Characteristics of the second group were a nodule or mass evident on radiographs and well-circumscribed tumor margins upon gross pathology. Lack of air bronchogram was an another radiographic feature in this group. Seventeen patients in these two groups underwent complete resection of the tumors and survived without recurrence, whereas four received chemotherapy after biopsy and survived with disease. These results indicate that primary pulmonary B-cell lymphoma is a low-grade malignancy and that complete resection is the only therapy which leads to cure. In a single patient with T-cell lymphoma, the radiographic and pathologic features of the tumor were indistinguishable from those in the first group, but the patient had an unfavorable prognosis. We consider that, from a prognostic viewpoint, it is important to determine the T- or B-immunophenotype of the tumor cells for diagnosis of primary pulmonary lymphoma. The only patient in this series with pulmonary lymphoma of LYG type showed distinctive clinicopathologic findings. We consider that this uncommon disease should be separated from other types of primary pulmonary lymphoma.

A 64-year-old male suffered from splenomegaly without lymphadenopathy. His WBC count on admission was 6.1 x 10(9)/l with 55% abnormal lymphocytes. No monoclonal gammopathy was detected. Abnormal cells shown in films usually had relatively abundant cytoplasm with serrated edges. Under phase-contrast microscopy, the cells displayed short, needle-like processes. The immunophenotype of peripheral blood mononuclear cells were CD19+, CD20+, CD11c+, FMC7+, CD5+, CD10-, CD25- and SIg+. The spleen histology showed a distinctive pattern of white pulp infiltration by abnormal lymphocytes with features of plasma cell differentiation. These findings were compatible with the features of splenic lymphoma with villous lymphocytes.

Twelve cases of leukaemic intermediate diffuse lymphocytic lymphoma (ILL), diagnosed by morphology, were analysed. The morphology of the ILL cells was so typical that it allowed ready distinction from chronic lymphocytic leukaemia (CLL) and other related B cell disorders. All cases were of B derivation, had strong mu and chi or lambda immunoglobulin (Ig) staining, were CD5 and FMC7 positive and CD10 negative. Cytogenetic abnormalities were found in 8 patients all having t(11;14)(q13;q32). DNA analysis revealed a relatively high incidence of hypoploidy. At diagnosis all the patients (9 males, 5 females; median age 68) had a low degree of absolute lymphocytosis but the disease was advanced and mostly widespread. The course of the disease appears to be aggressive and incurable with conventional combination chemotherapy.

Background: Primary cutaneous germinal center cell lymphomas (PCGCCL) are B-cell neoplasias; most are mixed cell type, composed of small and large cleaved cells and large noncleaved cells (centrocytes and centroblasts). Because of the significant pleomorphism of the cells, which ranged in size from small elements with indented nuclei to larger ones with multilobulated vesiculous nuclei, histopathologic examination of PCGCCL of mixed cell type has the worst degree of histologic interobserver reproducibility., Methods: In this study, the authors determined whether the light microscopic morphologic classification criteria applied in quantifying cleaved and noncleaved cells in these lymphomas are substantiated by morphometric analysis and have good reproducibility in differentiating the various cell subsets. They used an image analyzer (IBAS 2000, Zeiss Kontron, Munich, Germany) to study 17 centroblastic/centrocytic and centroblastic follicular and/or diffuse primary cutaneous lymphomas., Results: The data obtained showed morphometric differences between the follicular and diffuse patterns of neoplastic cells. In follicular neoplasms, the cells tend to be smaller, more cleaved, and more monomorphic than those observed in the diffuse forms. In all the follicular and diffuse cases, the authors observed a unimodal population with a wide peak composed of cells with intermediate morphometric features that cannot be labeled properly., Conclusions: These data underline the considerable overlap of nuclear parameters of lymphocytes between the subtypes of cells in cutaneous mixed small and large cell lymphoma, making the Kiel classification and Working Formulation unsuitable for this kind of neoplasia and supporting revision of classification criteria in cutaneous germinal center cell lymphomas.

Little is known about the role of tumor infiltrating T lymphocytes (TIL-T) in the pathogenesis of malignant diseases and collaboration between normal and malignant cells has not yet been proved. In the present work, we have investigated whether immune T lymphocytes exist in tumors invaded by B-cell non-Hodgkin's lymphoma (NHL) or Hodgkin's disease (HD). Therefore, we have studied the reactivity of the CD45RA monoclonal antibody, which discriminates between naive and memory CD4 T lymphocytes. Our results showed far lower percentages of CD4+ CD45RA+ in malignant lymphoma (30.3 +/- 15.0% in B-cell NHL, and 37.4 +/- 18.6% in HD) than in reactive hyperplasia (54.7 +/- 13.2%), leading to the conclusion of an accumulation of immune cells in tumor microenvironment. A further heterogeneity in the relative proportion of naive and memory TIL-T was also observed within lymphoma (range: 11 to 68% in B-cell NHL, 5 to 69% in HD). In B-cell NHL, it was related to histological features, as documented by the Kiel classification (P = .028), and to a stronger extent to cytological characteristics analysed with the Grenoble classification (P less than .0001): class 1 NHL, which are essentially indolent NHL displayed lower naive cells (22.2 +/- 7.4%) than class 3 NHL, which are more aggressive (40.1 +/- 16.1%). Among the monoclonal antibodies (mAb) defining the B-cell clone phenotype or activation state (CD19, CD20, CD21, CD22, CD23, CD24, CD5, CD10, CD11a, and Ki67), only CD23 (P = .0003) and Ki67 (P = .0007) revealed statistical association with the percentage of naive CD4 lymphocytes. No correlation could be demonstrated with the proportion of whole TIL-T, activated CD3 DR TIL-T, or CD4 subset.

A study was conducted to evaluate the usefulness of paraffin-immunohistochemistry for histopathological classification of non-Hodgkin's malignant lymphomas (NHML). the phenotypes of lymphoma cells and other cells were examined using 11 monoclonal and 3 polyclonal antibodies by the ABC method on paraffin-embedded tissue sections of 226 cases of NHML, comprising 94 B-cell lymphomas (B-ML) and 132 T-cell lymphomas (T-ML). In 219 NHML cases (96.8%), lymphoma cells reacted with more than one of these antibodies. A set of MB-1, Mx-pan B, L26, LN-1, LN-2 and anti-immunoglobulin light chain antibodies characterized each subtype of B-MLs, categorized according to the Kiel classification. Mantle-zone lymphoma (MzML) was added as one subtype. L26 stained the largest number of B-MLs (82.8%). B-cell chronic lymphocytic leukemia (B-CLL) was labeled most frequently by MB-1. MzML was characterized by reactivity of lymphoma cells with LN-2 and by the appearance of monoclonal immunoglobulin light chain along the cell membrane. Follicle center cell lymphomas were stained by LN-1 and LN-2, although a small number of proliferating cells were labeled by LN-1 in B-CLL, MzML and the immunocytoma lymphoplasmacytic/cytoid variant. MT-1 and/or UCHL-1 showed various degrees of reactivity with the cell membranes of lymphoma cells in 94.8% of T-MLs. Among the T-cell pleomorphic lymphomas of Suchi and Lennert, the adult T-cell leukemia/lymphoma type, defined by stippled heterochromatin distribution and peculiar huge cells, reacted selectively (p less than 0.05) with anti-phosphokinase C antibody. Anaplastic large cell T-ML reacted with a set of Ber H2, LN-2 and Leu M1. In T-zone lymphomas without hyperplastic follicles, angioimmunoblastic lymphadenopathy with dysproteinemia-type T-ML, lymphoepithelioid cell lymphomas and some pleomorphic lymphomas comprising clear large lymphoma cells, there were many intermingling B cells, and their constitution varied. In some lymphoblastic lymphomas of both the T cell and B-cell type, phenotypes of T cells and B cells were expressed. Consequently, it was shown that paraffin immunohistochemistry was useful for the practical histopathological diagnosis of NHML even in the area where human T-cell leukemia virus type 1 is endemic.