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Transcriptional profiling suggests that secondary and primary large B-cell lymphomas of the gastrointestinal (GI) tract are blastic variants of GI marginal zone lymphoma.

The pathogenetic relationship of marginal zone B-cell lymphoma (MALT lymphoma) of the gastrointestinal (GI) tract and eventually co-existing aggressive B-cell lymphoma and primary aggressive B-cell lymphoma remains to be elucidated. The RNA of laser-microdissected cells was isolated and amplified from small and/or large cell compartments of eight MALT lymphomas (small cell lymphoma, SCL), 14 GI diffuse large B-cell lymphomas (large cell lymphoma, LCL), and ten GI B-cell lymphomas with composite small and large cell compartments (ComL) and expression analyses were performed using cDNA arrays. Hierarchical cluster analysis clearly separated SCL and LCL and the small and large cell compartments of ComL. Likewise, cluster analysis with all samples of SCL, LCL, and ComL yielded two main 'small cell' and 'large cell' branches. Furthermore, 60 genes were differentially expressed between SCL and LCL, and 82 genes between the small and large cell components of ComL; 26 genes were discriminators in both settings. Use of the profiles of ComL as training sets for class prediction resulted in 95% accuracy for the classification of SCL and LCL. Collectively, the data strongly suggest that both secondary and primary aggressive B-cell lymphomas of the GI tract are blastic marginal zone lymphomas.

Gastrointestinal Neoplasms↗

CD26/dipeptidyl peptidase IV expression in human lymphomas is restricted to CD30-positive anaplastic large cell and a subset of T-cell non-Hodgkin's lymphomas.

CD26 is identical to the cell surface ectoenzyme dipeptidyl peptidase IV (DPPIV). CD26/DPPIV is associated with T-cell activation and proliferation and also may function as an auxiliary adhesion factor. Although CD26/DPPIV has been previously studied on lymphoid populations and on leukemias/lymphomas of B- and T-cell phenotype, little is known about its expression and functional role in some specific types of lymphomas, such as CD30-positive anaplastic large cell (ALC) lymphomas and Hodgkin's disease (HD). A series of 81 lymphoma samples, including 23 cases of HD, 17 cases of CD30-positive ALC lymphomas, 41 cases of other non-Hodgkin's lymphomas (NHL), and a panel of HD- or ALC lymphoma-derived human cell lines were evaluated for CD26/DPPIV expression by enzyme histochemistry and immunohistochemistry on frozen sections and cell smears. CD26/DPPIV protein was expressed on neoplastic cells in 12 of 17 (71%) ALC lymphomas irrespective of their antigenic phenotype and in seven of 15 (47%) T-cell NHLs. In contrast, we did not detect CD26/DPPIV expression in tumor cells from 26 cases of B-cell NHL other than ALC lymphomas or in Reed Sternberg (RS) cells and variants of 21 of 23 HD cases. Accordingly, CD26/DPPIV expression was maintained on the CD30-positive ALC lymphoma cell line Karpas 299, but the molecule was not detected on HD-derived cell lines of B, T, or non-B non-T phenotype. These results may support a new potential tool for the phenotypic separation of ALC lymphomas from HD based on the differential expression of the CD26/DPPIV molecule. Moreover, given the demonstration that CD26/DPPIV is identical to the human adenosine deaminase (ADA) binding protein, it could be speculated that CD26/DPPIV also may function by interacting with ADA to regulate the growth of CD26/DPPIV expressing neoplastic cells in ALC lymphomas.

Dipeptidyl Peptidase 4↗

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

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

Adult↗

T-cell rich b-cell non-hodgkin's lymphoma: a progressed form of follicle centre cell lymphoma and lymphocyte predominance hodgkin's disease.

T-cell rich B-cell non-Hodgkin's lymphoma (T-cell rich B-cell lymphoma) is a morphological variant of diffuse large B-cell lymphoma. It is important to recognize this variant in the differential diagnosis of T-cell non-Hodgkin's lymphoma. The main differential diagnosis of T-cell rich B-cell lymphoma, nodular and diffuse lymphocyte predominance Hodgkin's disease (lymphocyte predominance Hodgkin's disease), is, however, even more difficult and differentiating criteria are still not satisfactorily defined. Moreover, T-cell rich B-cell lymphoma may not represent a clinicopathological entity. Twelve cases of T-cell rich B-cell lymphoma, selected on the basis of morphology and limited immunohistochemistry without previous knowledge of clinical data, were studied by immunohistochemistry and polymerase chain reaction for bcl-2 rearrangements to investigate the histogenetic background. In three of 12 cases, bcl-2 rearrangements were found, strongly suggesting a follicle centre cell origin. In three other cases, a documented history of definite nodular lymphocyte predominance Hodgkin's disease 29 months to 20 years prior to the diagnosis of the lymphoma was present. No differences in growth pattern, residual nodularity, tumour cell distribution, cellular morphology and composition, or immunophenotypical differences were noted in these six cases as compared to the remaining cases. These data underscore the histogenetic diversity in T-cell rich B-cell lymphoma and identify it as a progressed form of lymphoma derived from entities as diverse as follicle centre cell lymphoma and nodular lymphocyte predominance Hodgkin's disease. Moreover, it shows a complete morphological overlap with the diffuse form of lymphocyte predominance Hodgkin's disease and may actually encompass this disease entity.

Adult↗

KSHV-positive solid lymphomas represent an extra-cavitary variant of primary effusion lymphoma.

Primary effusion lymphoma (PEL) is a unique form of non-Hodgkin lymphoma (NHL) associated with Kaposi sarcoma-associated herpesvirus (KSHV; HHV-8) that displays a distinct constellation of clinical, morphologic, immunologic, and molecular characteristics. Rare KSHV-containing immunoblastic lymphomas occurring in solid tissues have been described. Whether they represent part of the spectrum of PEL has not been determined. The morphologic, immunophenotypic, and molecular features of KSHV-positive solid lymphomas occurring in 8 HIV+/AIDS patients were systematically investigated and compared with those of 29 similarly analyzed PELs. The 8 KSHV-positive solid lymphomas were virtually indistinguishable from the 29 PELs based on morphology (immunoblastic/anaplastic), immunophenotype (CD45 positive; T cell antigen negative; CD30, EMA, CD138 positive; CD10, CD15, BCL6 negative) and genotype (100% immunoglobulin genes rearranged; no identifiable abnormalities in C-MYC, BCL6, BCL1, BCL2; and uniformly EBV positive). The only identifiable phenotypic difference was that the KSHV-positive solid lymphomas appeared to express B cell-associated antigens (25%) and immunoglobulin (25%) slightly more often than the PELs (<5% and 15%, respectively; P = 0.11 and P = 0.08, respectively). The clinical presentation and course of the patients who develop KSHV-positive solid lymphomas were also similar, except for the lack of an effusion and somewhat better survival (median 11 months vs. 3 months). However, the 3 KSHV-positive solid lymphoma patients alive without disease 11, 25, and 44 months following initial presentation were recently diagnosed patients and, unlike the other patients with KSHV-positive solid lymphomas, received anti-retroviral therapy. These findings strongly suggest that these decidedly rare KSHV-positive solid lymphomas belong to the spectrum of PEL. Therefore, we propose that the KSHV-positive solid lymphomas be designated extra-cavitary PELs.

Adult↗

Variable frequencies of t(11;18)(q21;q21) in MALT lymphomas of different sites: significant association with CagA strains of H pylori in gastric MALT lymphoma.

t(11;18)(q21;q21) is a specific chromosomal translocation associated with mucosa-associated lymphoid tissue (MALT) lymphoma. It fuses the amino terminal of the API2 gene to the carboxyl terminal of the MALT1 gene and generates a chimeric fusion product. Although the translocation is frequently detected in gastric and pulmonary MALT lymphoma, its incidence in MALT lymphomas from other sites is largely unknown. It also remains unknown whether the occurrence of the translocation is influenced by the nature of preceding diseases associated with MALT lymphomas. We screened for t(11; 18)(q21;q21) in 417 cases of MALT lymphoma from 8 major sites by reverse transcription-polymerase chain reaction. t(11;18)(q21;q21) was found at highest frequencies in MALT lymphomas from the lung (38%) and stomach (24%), and at moderate frequencies in those from the conjunctiva (19%) and orbit (14%). However, the translocation was found only rarely in MALT lymphomas from the salivary gland (1%) and was absent in those from the thyroid, skin, liver, and other rare sites, and in immunoproliferative small intestinal disease (IPSID). In gastric MALT lymphoma, t(11;18)(q21;q21) was significantly associated with infection by CagA-positive strains of Helicobacter pylori. As CagA-positive strains of H pylori are much more potent in induction of host inflammatory responses, including activation of neutrophils, which release highly genotoxic oxygen reactive species, we therefore examined neutrophil infiltration in recognized precursors of MALT lymphoma including H pylori-associated gastritis, lymphoepithelial sialadenitis, and Hashimoto thyroiditis. Neutrophil infiltration was prominent in H pylori-associated gastritis but not in lymphoepithelial sialadenitis and Hashimoto thyroiditis. Our results demonstrate that t(11;18)(q21; q21) occurs at markedly variable frequencies in MALT lymphoma of different sites and suggest that the occurrence of the translocation is influenced by the nature of premalignant diseases associated with MALT lymphoma. Oxidative damage might play a role in development of t(11;18)(q21; q21).

Adaptor Proteins, Signal Transducing↗

Splenic marginal zone lymphoma: a distinctive type of low-grade B-cell lymphoma. A clinicopathological study of 13 cases.

The recognition and classification of the different varieties of splenic low-grade B-cell lymphomas have been hampered by the rarity of histological studies of surgical splenectomy specimens of B-cell lymphoma. In an effort to characterize the recently described splenic marginal zone lymphoma (SMZL), we conducted a survey of 13 patients with this type of tumor using the criteria defined by Schmid for its recognition (Schmid et al., Am J Surg Pathol 1992;16:455-66). Primary splenic high-grade lymphomas, T-cell lymphomas, and secondary infiltration by other recognized low-grade B-cell lymphomas, with the exception of splenic lymphoma with villous lymphocytes, were excluded. This selection gave rise to a homogeneous group of tumors with similar clinical, histological, immunohistochemical, and molecular features. Our study showed the critical parameters for their recognition to be morphological, including macroscopic micronodularity and the constant presence of white- and red-pulp infiltration, marginal zone pattern, and plasmacytic differentiation. No t(14;18) or PRAD-1/cyclin D1 overexpression was detect able in any case. Clinically, the tumors were widespread with a protracted evolution. Nodal infiltration by SMZL in our cases was morphologically similar to monocytoid B-cell lymphoma. SMZL could constitute the largest group of primary splenic malignant lymphomas, partially overlapping with splenic lymphoma with villous lymphocytes. Specific molecular markers for SMZL have yet to be defined. Because of the limited number of cases, the question of therapy for this group of lymphomas must remain open for the future.

Aged↗

A pathologic study of childhood lymphoma in Taiwan with special reference to peripheral T-cell lymphoma and the association with Epstein-Barr viral infection.

The authors retrospectively reviewed the clinicopathologic and immunologic features of 65 consecutive cases of childhood lymphoma reported between 1980 and 1989. Southern blot hybridization was also performed in 23 cases to study their association with Epstein-Barr virus (EBV) and human T-cell leukemia virus type 1 (HTLV-1). The 65 cases included 56 non-Hodgkin's lymphoma (NHL) (86%) and 9 Hodgkin's disease (HD) (14%). The NHL could be classified into the following groups: Group I, small noncleaved cell lymphoma (20 cases); Group II, lymphoblastic lymphoma (17 cases); Group III, large cell lymphoma (17 cases); and miscellaneous (2 cases). There was no follicular lymphoma case. Immunohistochemical study on paraffin sections and/or frozen specimens in 47 cases of NHL showed that all the Group I cases belonged to B-cell neoplasm (17 of 17 cases); most of the Group II cases belonged to T-cell neoplasm (9 of 14 cases); and most of the Group III cases were peripheral T-cell lymphoma (PTL) (8 of 16 cases), including 2 cases of Ki-1 lymphoma. The majority of childhood NHL belonged to high-grade malignancy with an aggressive clinical course (median survival time, 8 months). The EBV DNA could be detected from the tumor tissues in 4 of 6 PTL, but in none of the remaining 19 cases of NHL including 6 Burkitt's type lymphomas. HTLV-1 proviral genome was not detected in all specimens examined. The authors concluded that the distribution pattern and clinicopathologic feature of childhood lymphoma in Taiwan are comparable to that in Japan and western countries. The frequent association of EBV with aggressive PTL was unique and deserves additional investigation.

Adolescent↗

Clinicopathologic and genotypic study of extranodal nasal-type natural killer/T-cell lymphoma and natural killer precursor lymphoma among Koreans.

BACKGROUND: This study aimed to define genotypic profile and to describe the clinicopathologic features of nasal-type natural killer (NK)/T-cell lymphoma of nasal and extranasal origin and NK precursor lymphoma. METHODS: NK/T-cell lymphomas from the upper aerodigestive tract (n = 45), skin (n = 2), gastrointestinal tract (n = 3), and soft tissue (n = 2) and NK precursor neoplasms (n = 3) were studied. Immunophenotype was analyzed by immunohistochemistry and flow cytometry. In situ hybridization with EBER 1/2 RNA probes was performed. T-Cell Receptor (TCR)-gamma gene rearrangement was analyzed by seminested polymerase chain reaction with heteroduplex analysis. Overall survival rate was correlated with clinicopathologic parameters and compared by Wilcoxon test. RESULTS: Clonal TCR-gamma gene rearrangement was detected in 3 of 31 upper aerodigestive and 1 of 2 skin tumors. When immunostained using paraffin embedded tissue, 6 upper aerodigestive lymphomas were negative for CD56 in which 4 cases lacked clonal TCR gene rearrangement. Epstein-Barr virus (EBV) mRNA was detected in 33 upper aerodigestive tumors including 26 of 29 nasal tumors (90%), and 7 of 10 extranasal tumors (70%). There was no histologic, immunophenotypic, or genotypic differences according to the lineage and EBV association in upper aerodigestive lymphomas. Among the patients with upper aerodigestive tumors, overall 1-year survival rate was 41%, and correlated well with the stage (P < 0.05) but not with the size of tumor cells, EBV status, and lineage (P > 0.05). Median survival rate of lymphomas from other sites excluding upper aerodigestive tract was not significantly different from that of upper aerodigestive lymphomas with same stage (P > 0.05). Unlike nasal-type NK/T-cell lymphomas, NK precursor lymphoma involved the bone marrow and lymph nodes at initial presentation or in the course of disease. Tumor cells were positive for TdT in all and myeloid markers in two. TCR gene rearrangement was germ line. CONCLUSIONS: Most upper aerodigestive nasal-type NK/T-cell lymphomas among Koreans are genotypically of NK derivation and few belong to T lineage. Presence or absence of EBV has no significant correlation with the histologic changes and the lineage of these lymphomas.

Adult↗

Most CD56+ intestinal lymphomas are CD8+CD5-T-cell lymphomas of monomorphic small to medium size histology.

The expression of the natural killer (NK) cell marker CD56 has been reported to occur in NK cell lymphomas/leukemias and a small group of peripheral T-cell lymphomas but has not been studied extensively in primary intestinal non-B-cell lymphomas. Normal human jejunal intraepithelial lymphocytes (IELs) are mainly T-cell receptor (TCR)-alphabeta+CD3+CD8+CD5low and include an approximately 15% fraction of CD56+ cells that could be the cells of origin for CD56+ intestinal T-cell lymphoma (ITL). To test this hypothesis, 70 cases diagnosed as ITL were immunophenotyped, and 15 CD56+ cases (21%) were identified. The majority of the CD56+ lymphomas was of monomorphic small to medium-sized histology, shared the common phenotype betaF1+/-CD3epsilon/cyt+CD8+CD4-CD5-CD57-TIA-1+ and had clonally rearranged TCR gamma-chain genes. In contrast, the CD56- lymphomas were mainly composed of pleomorphic medium and large cells or had a morphology most consistent with anaplastic large-cell lymphoma and were mostly CD8-. These findings suggest that the majority of CD56+ intestinal lymphomas are morphologically and phenotypically distinct T-cell lymphomas most likely derived from activated cytotoxic CD56+CD8+ IELs. Some overlapping histological and clinical features between CD56+ and CD56- ITLs indicate that the former belong to the clinicopathological entity of ITL. The consistent expression of cytotoxic-granule-associated proteins introduces ITL (both CD56+ and CD56-) into the growing family of usually aggressive extranodal lymphomas of cytotoxic T-cell and NK-cell derivation. In contrast to putative NK-cell lymphoma of the sinonasal region, intestinal NK-cell lymphoma seems to be very rare.

Adult↗

Selective cytotoxicity of two rodent T cell lymphomas to rat yolk sac tumours involves a retroviral envelope protein expressed by the lymphoma.

A Gross virus induced rat T cell lymphoma G1-Tc1 and a Moloney virus induced mouse T cell lymphoma YAC-1 are shown to exert a strong cytotoxic activity against rat yolk sac tumours but not to various types of rat, mouse or human normal cells or tumour cell lines including carcinomas, sarcomas, lymphomas and gliomas. Both lymphomas are CD3+, CD4-, CD8- and T-cell receptor (TCR) alpha beta +. The cytotoxicity was not MHC restricted or dependent on the density of MHC class I of the target cells, and the mouse lymphoma killed the rat yolk sac tumour target. The cytotoxic action was fast and up to 80% specific killing was observed in 4-h 51Cr release assays. A rat B cell hybridoma was established from a Wistar/Furth (WF) rat immunized with the syngeneic lymphoma G1-Tc1 producing an immunoglobulin (Ig)G2c monoclonal antibody (MoAb) 1F2. This binds to the lymphomas G1-Tc1 and YAC-1 and also to a murine non-cytolytic Rauscher lymphoma RMA, but not to any other of several rat, mouse or human cell types tested. The 1F2 completely inhibited the killing of rat yolk sac tumours by the two cytolytic lymphomas, but did not interfere with the killing mediated by natural killer (NK) cells or cytolytic lymphokine-activated killer (LAK) cells. Immunochemical analysis of solubilized cell membranes of the lymphoma G1-Tc1 demonstrates that the 1F2 antibody recognizes an epitope on a retroviral gp 70 envelope protein. This indicates that a retroviral protein is involved in the lytic activity of the two lymphomas.

AKR murine leukemia virus↗

Primary bony peripheral T-cell lymphoma mimicking nasal type NK/T-cell lymphoma: a case report.

Primary bony lymphomas are rare, and nearly all are high-grade B-cell lymphomas. Natural killer (NK)/T-cell lymphomas are highly aggressive lymphomas of NK- or T-cell lineage with predominant extranodal presentation and are divided into nasal and nasal-type (extra-nasal). We report a primary bony peripheral T-cell lymphoma mimicking NK/T-cell lymphoma, nasal type. A 22-year-old Taiwanese male presented with a frontal skull bone mass noted for 3 weeks, and received craniectomy with tumor removal. His tumor showed extensive coagulative necrosis with angioinvasion by large lymphoma cells expressing CD2, CD8, CD16, CD43, CD45, CD45RO, CD56, T-cell intracellular antigen-1, and granzyme B, but not CD3, CD4, CD20, CD57, CD68, and betaF1. In situ hybridization for Epstein-Barr virus-encoded mRNA was negative. Polymerase chain reaction study of formalin-fixed tissue showed clonal rearrangement of the T-cell receptor-gamma chain gene. The diagnosis was peripheral T-cell lymphoma, unspecified subtype. The initial stage was I(EA). His lymphoma was refractory to chemotherapy, and bony metastases developed in the right iliac bone 2 months later. He died of disease after 6 months without autopsy. We emphasize the importance of detailed immunohistochemical and gene rearrangement studies for the classification of malignant lymphomas via a very rare primary bony lymphoma of peripheral T-cell subtype.

Adult↗

Differential diagnosis between classic Hodgkin's lymphoma, T-cell-rich B-cell lymphoma, and paragranuloma by paraffin immunohistochemistry.

There are significant difficulties in the differential diagnosis of lymphomas at the interface between classic Hodgkin's lymphoma and both paragranuloma and T-cell-rich B-cell lymphoma as well as at the interface between T-cell-rich B-cell lymphoma and paragranuloma. We therefore investigated 197 cases (155 classic Hodgkin's lymphomas, 32 T-cell-rich B-cell lymphomas, and 10 paragranulomas) by paraffin immunohistochemistry. Special interest was given to cases with a B-cell phenotype of tumor cells. The reactive inflammatory infiltrate in both classic Hodgkin's lymphoma and T-cell-rich B-cell lymphoma was rich in TIA-1-positive cytolytic lymphocytes, and CD57-positive cells were rarely encountered. In contrast, in paragranuloma CD57-positive cells and small B-lymphocytes predominated the background infiltrate. The tumor cells in cases of classic Hodgkin's lymphoma were positive for CD30 in 95%, for CD15 in 75%, and for CD20 in 22%. Apart from this, vimentin was expressed in >95% of the cases. All cases of T-cell-rich B-cell lymphoma were negative for vimentin, CD30, and CD15. The reactivity of the tumor cells for CD30, CD15, CD20, and vimentin together with the background reactivity for CD57 and TIA-1 seem to reliably discriminate between the entities and should therefore help to increase the interobserver reproducibility of diagnoses in the gray zone around Hodgkin's lymphoma.

Antigens, CD20↗

Bacterial lymphadenitis with the picture of a lymphoepithelioid cell lymphoma--Lennert's lymphoma.

Three cases with the typical light microscopic picture of lymphoepithelioid cell lymphoma (so-called Lennert's lymphoma) were investigated by electron microscopy. Surprisingly, Lennert's lymphoma could be excluded in two cases. These two cases exhibited, in addition to pleomorphic lymphocytes and epithelioid cells, macrophages with accumulations of bacteria, indicating that a bacterial infection was the cause of the disease. By comparing the typical case of Lennert's lymphoma with the other cases, we found several criteria for distinguishing between Lennert's lymphoma and bacterial lymphadenitis. In bacterial lymphadenitis: (1) small and medium-sized lymphocytes exhibited a wide cytological spectrum whereas the lymphocytes in Lennert's lymphoma were relatively uniform; the lymphocytes with prominent lysosome-like granules found in Lennert's lymphoma were not seen; (2) cytology and distribution of epithelioid cells were similar to those in Lennert's lymphoma; (3) epithelioid venules contained recirculating lymphocytes, which were rarely found in Lennert's lymphoma; (4) numerous interdigitating reticulum cells, fibroblasts and myofibroblasts were seen, but not in Lennert's lymphoma; (5) focal increase in reticulin fibres was the main difference in light microscopy; (6) rod-shaped bacteria were accumulated in the cytoplasm of a few macrophages. The presence of bacteria could not be demonstrated unequivocally by light microscopy. In both cases the large number of intracytoplasmic bacteria suggests that this unusual and until now unknown lymphadenitis is the result of an infection caused by facultative intracellular parasitic bacteria. The outcome of bacterial lymphadenitis that gives the false impression of Lennert's lymphoma is uncertain. Cure was achieved in one of our cases. The other patient died before therapy was commenced.

Adult↗

Aggressive Lennert's lymphoma: report of three cases in comparison to non-aggressive Lennert's lymphoma.

The present article describes three cases of Lennert's lymphoma exhibiting aggressive clinical courses. These cases were accompanied by disseminated intravascular coagulation (DIC) or hemophagocytic syndrome (HPS). These cases were compared to non-aggressive type of Lennert's lymphoma. Of the three cases, two demonstrated involvement of the liver and the other possessed bone marrow involvement. In one patient, while a lymph node biopsy revealed Lennert's lymphoma histologically, a liver biopsy obtained 2 months later revealed a high-grade large cell cytotoxic T-cell lymphoma. Two of these cases showed HPS and the other exhibited DIC. All patients died within 1 year of diagnosis, with the shortest survival period being 1.5 months. Immunohistochemically, lymphoma cells were CD8+, CD4-, granzyme B+, and T-cell intracellular antigen-1 (TIA-1)+, showing a cytotoxic T-cell phenotype. Two cases demonstrated positive reactivity for Epstein-Barr virus in lymphoma cells by in situ hybridization. These cases were compared with eight cases of non-aggressive Lennert's lymphoma. In comparison to non-aggressive disease, these three cases displayed a higher percentage of Ki-67-positive cells. In conclusion it was found that a subset of Lennert's lymphoma cases share common features with high-grade cytotoxic T-cell lymphoma, indicating that Lennert's lymphoma may be part of the spectrum of cytotoxic T-cell lymphoma.

Aged↗

Clinicopathogenetic significance of chromosomal abnormalities in patients with blastic peripheral B-cell lymphoma. Kiel-Wien-Lymphoma Study Group.

So far, reproducible histomorphologic and immunological criteria to distinguish clinicopathologic subtypes of blastic peripheral B-cell non-Hodgkin's lymphoma (BBCL), especially centroblastic (cb) and immunoblastic (ib) lymphomas, for daily diagnostic use are still lacking. Therefore, we correlated the cytogenetic findings in 126 patients with BBCL with histopathologic diagnoses. Subclassification of cb and ib lymphomas relied on the criteria defined in the updated Kiel classification; these subtypes are also listed in the Revised European-American Lymphoma (REAL) classification and in a preliminary report on the newly established World Health Organization classification, to investigate their clinical significance. Moreover, we performed a multivariate analysis to compare the prognostic significance of cytogenetic findings with the International Index. There were significant differences in the frequency of chromosome aberrations between different BBCL subtypes: t(8;14) was predominantly present in Burkitt's lymphomas, t(14;18) in centroblastic lymphomas, deletions in 8q and 14q, changes of 4q and losses of chromosome 10 in immunoblastic lymphomas; t(11;14) was restricted to blastoid mantle cell lymphomas and associated with a poor prognosis. In cb lymphomas, deletions in 1q42-qter, duplications in 1q23-32, trisomy 5, and changes of 15q were identified as independent prognostic factors. In ib lymphomas, changes of 7q and 8q had stronger impact on survival than the International Index. These findings underline that Burkitt's, cb, ib, and blastoid mantle-cell lymphoma are biologically distinct and clinically relevant entities and that cytogenetic findings can be helpful to subtype BBCL.

Biomarkers, Tumor↗

Observations on lymphomagenesis and lymphoma in AKR mice. A description of prelymphoma changes in the thymus and phenotypic diversity of lymphomas induced by SL3-3 virus.

These studies were designed to look for a correlation of intrathymic survival of virus-infected thymocytes with lymphomagenesis. Cells from the normal-appearing prelymphoma thymus of SL3-3 virus-treated AKR mice were studied. Also, phenotypic properties of the malignant cells from the virus-induced lymphomas are described. In this model system, 100% of mice inoculated with virus at three days of age develop thymic lymphoma between 60 and 90 days of age. The experiments show that cells with malignant potential do not appear in the thymus until 36 days after virus inoculation. These cells are initially thymus-dependent (TD) in that they produce lymphoma of donor-type in recipients after intrathymic inoculation with long latency. They do not produce lymphoma after subcutaneous inoculation in syngeneic hosts. At 39 days after virus inoculation, the first thymus independent (TI) lymphoma cells appear. These cells, like the cells isolated from thymi with overt tumors, produce lymphoma of donor-type after a short latency when inoculated by the intrathymic or subcutaneous route. Thymocytes from normal-appearing thymi of mice at 42 days after virus inoculation, which could be expected to include TD, TI or no lymphoma cells, were evaluated for their ability to survive in a recipient thymus for three weeks after intrathymic inoculation. They were compared to thymocytes from age-matched control mice. Thymi receiving the virus-infected thymocytes showed 15% to 80% donor cells at three weeks. The highest numbers of donor cells were from thymi which were shown to contain TI lymphoma cells. However, cells from thymi with TD and no lymphoma cells could also be detected in significant numbers at three weeks after intrathymic inoculation. Less than 2% of donor-type thymocytes could be found after inoculation of thymocytes from normal control AKR mice. These data provide evidence that virus infection of thymocytes, even before the appearance of cells with lymphomagenic potential, endows them with a capacity for prolonged intrathymic survival. This appears to be a necessary step for tumor progression in this model. A remarkable phenotypic diversity of the virus-induced lymphomas was shown. The effect of various growth environments, intrathymic, subcutaneous, and in vitro on lymphoma cell phenotypic expression revealed individual differences in each tumor and in each environment.

Animals↗

Molecular genetics of gastrointestinal non-Hodgkin's lymphomas: unusual prevalence and pattern of c-myc rearrangements in aggressive lymphomas.

Thirty-two extranodal lymphomas of the gastrointestinal (GI) tract underwent molecular genetic analysis by Southern blotting using probes for the immunoglobulin genes and the bcl-1, bcl-2, and c-myc loci, commonly involved in lymphomagenesis. No bcl-1 rearrangements were found. There was only one large-cell lymphoma with a bcl-2 rearrangement. A rearrangement of the c-myc gene was found in six of eight Burkittlike lymphomas of the intestine. In five of these six cases, a chromosomal translocation t(8;14) with an unusual breakpoint was demonstrated by comigration of the rearranged c-myc and a rearranged JH sequence. This pattern of rearrangement has not been previously associated with a specific group of non-Hodgkin's lymphomas. In contrast to all six low-grade lymphomas, c-myc rearrangements were found in 6 of 12 large-cell or high-grade mucosa-associated lymphomas of the stomach. No comigration of c-myc and immunoglobulin heavy-chain gene sequences were found. We conclude that primary GI lymphomas have different molecular genetic characteristics compared with node-based follicle center-cell lymphoma and as a group are not related to these lymphomas. In addition, the prevalence and patterns of c-myc rearrangements in the gastric large-cell lymphomas and ileocecal Burkittlike lymphomas are noteworthy and suggest a different and distinct pathogenesis for these tumors.

Blotting, Southern↗