Amplification of the MLL gene on double minutes, a homogeneously staining region, and ring chromosomes in five patients with acute myeloid leukemia or myelodysplastic syndrome

Most entities of B-cell malignant non-Hodgkin's lymphomas (NHL) are characterized by typical primary chromosomal changes such as the t(14;18) in follicular lymphoma or the t(11;14) in mantle cell lymphoma. In contrast, marginal zone B-cell lymphomas (MZBL), arising at different nodal and extranodal sites, are poorly characterized on the genetic level. We performed cytogenetic investigations in 20 splenic and in 10 nodal MZBL and analyzed 52 MZBL (including 12 MALT-type lymphomas) for deletions of TP53, D13S25, and RB1 loci by fluorescence in situ hybridization. A new nonrandom chromosomal aberration, del(10)(q22q24), was found as a clonal anomaly in 3 out of 20 cases of splenic MZBL. Further recurring abnormalities such as del(7q) or trisomy 3 were found to be characteristic chromosomal changes in a subset of splenic MZBL. TP53 was deleted in 5/25 cases of splenic MZBL. Deletions involving band 13q14 were only rarely encountered, challenging a previous report that stated a dissociated D13S25-RB1 status as characteristic in splenic MZBL. There are fundamental differences between the different subtypes of marginal zone lymphomas as defined with current classification schemes. Splenic MZBL, in contrast to most other entities of B-cell NHL, seems to constitute a heterogeneous disease especially with regard to genetic alterations. del(10)(q22q24) could be of importance at least in a subset of this lymphoma entity.     

Follicular colonization of nodal marginal-zone B-cell lymphoma resembling follicular lymphoma: report of 6 cases

The formation of neoplastic B-cell follicles is accepted as a diagnostic criterion of follicular lymphoma. However, extranodal marginal-zone B-cell lymphomas (MZBLs) of mucosa-associated lymphoid tissue (MALT) type also sometimes contain numerous lymphoid follicles and may even have a predominantly follicular growth pattern. However, morphologic, immunohistochemical, and genotypic findings suggest that lymphoid follicles in extranodal MZBLs are neoplastic follicles formed as the result of colonization of previously reactive follicles by tumor cells (centrocyte-like cells). We present here 6 cases of nodal MZBL demonstrating a follicular growth pattern. Immunohistochemical study demonstrated that the tumor cells were CD10-, CD20+, CD79a+,CD138-, Bcl-2+, Bcl-6- and IRF4+. Residual nonneoplastic follicular center cells were CD10+, CD20+, CD79a+, Bcl-2-, and Bcl-6+. CD21/CD23 immunostain demonstrated a disrupted follicular dendritic cell pattern characteristic of follicular colonization in extranodal MZBL of MALT type. Taken in conjunction with the morphologic findings, nodal MZBL may also show a follicular growth pattern similar to extranodal MZBL of MALT type. The marginal-zone nature is most recognizable on immunohistochemistry, although the histologic appearance alone may cause some diagnostic problems. It is important for pathologists to consider this type of lesion in diagnostic practice.     

A reassessment of primary thyroid lymphoma: high-grade MALT-type lymphoma as a distinct subtype of diffuse large B-cell lymphoma

AIMS: Primary lymphoma of the thyroid gland (PTL) is a relatively rare disease. During an 18-year period, 53 cases of primary non-Hodgkin's lymphoma involving this extranodal site were seen at our institutions. The aims of this study were to evaluate the spectrum of PTLs using current lymphoma classification concepts and immunocytochemical markers, determine whether features of MALT-type lymphoma were evident in PTL, and if there was any clinical significance of such a finding. METHODS AND RESULTS: The cases were retrospectively studied clinically, histologically and immunohistochemically. The tumours were classified according to the Revised European-American Lymphoma Classification of lymphoid malignancies (REAL classification). Thirty-eight patients were females, 15 were males and mean age at diagnosis was 66.3 years (range 38-90). Three cases were low-grade marginal zone lymphomas (low-grade MALT-type lymphomas). There were 45 diffuse large B-cell lymphomas (DLBCL) of which there were 27 DLBCL-NOS and 18 high-grade MALT-type lymphomas. Within the diffuse large B-cell lymphoma (DLBCL) category, cases were subdivided into those without (DLBCL-NOS) and those with features of 'high-grade' MALT-type lymphoma based on presence of a low-grade component or large cell lymphoepithelial lesions (HG MALT-type lymphoma). In addition there were three follicle centre lymphomas, one anaplastic large cell lymphoma and one peripheral T-cell lymphoma. Twenty cases were stage IE, 18 stage IIE, and four stage IV. All patients with low-grade MALT-type lymphoma are alive without disease. The 5-year survivals for DLBCL-NOS and HG MALT-type lymphoma were 75% and 25%, respectively. Univariate analysis (log rank) among the DLBCLs showed stage (P < 0.001) and subtype (P = 0.005) were associated with survival. Stage was associated with type of DLBCL, 65% of DLBCL-NOS being stage IE compared to 20% of HG MALT-type lymphomas. CONCLUSIONS: We conclude that primary thyroid lymphomas occur most commonly in elderly women and are frequently present in clinical stage IE and IIE. Low-grade MALT-type lymphomas are relatively uncommon but appear to have a favourable prognosis. DLBCL is the most common lymphoma and features of MALT can be seen in over one-third of cases. As a group, HG MALT-type lymphomas had a worse outcome than DLBCL-NOS, primarily due to higher clinical stage at diagnosis. These two subtypes of DLBCL appear to be distinct clinical and histological entities.     

Molecular-cytogenetic comparison of mucosa-associated marginal zone B-cell lymphoma and large B-cell lymphoma arising in the gastro-intestinal tract.

Extranodal B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) type may represent a model of lymphoma progression, because a small cell component frequently occurs in the large cell variants. We studied 52 extranodal B-cell lymphomas: 18 extranodal marginal zone B-cell lymphomas of MALT type (MZBL,MT), 7 MZBL,MT of the gastro-intestinal tract with a diffuse large B-cell component (giMZBLplusLBCL), and 27 diffuse large B-cell lymphomas of the gastro-intestinal tract without small cell component (giLBCL). Analytical techniques were comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH). The translocation t(11;18) was found as the sole aberration in two MZBL,MT only. In contrast to this, t(11;18)-negative MZBL,MT were characterized by frequent gains on chromosome 3 and DNA amplifications on 2p13-p15. Furthermore, we found a clonal lymphoma progression from the small to the large cell component with accumulation of gains and losses of chromosomal material in the large cell component in giMZBLplusLBCL. Aberrations overlapping with MZBL,MT and giMZBLplusLBCL included losses on chromosome 13, amplifications of the REL proto-oncogene, or gains on chromosome 12. In addition, the large cell component revealed gains on 8q24, including amplifications of the MYC proto-oncogene, and losses on 2q. The giLBCL had frequent gains on chromosomes 12 and 9, as well as on 11q, and losses on 6q. We conclude that, based on the distinctive and partly overlapping patterns of genetic aberrations, MALT lymphomas can be divided into different genetic subgroups.     

Classical Hodgkin lymphoma concurrently evolving in a patient with marginal zone B-cell lymphoma of the spleen

Combination of the splenic marginal zone B-cell lymphoma (SMZL) and classical Hodgkin lymphoma (cHL) is extremely rare. We report a unique case with concurrent SMZL and cHL. The patient was a 63-year-old man who presented with fatigue and anemia, showing a splenomegaly and retroperitoneal lymphadenopathy. A splenectomy revealed monotonous marginal zone lymphocytic infiltrates and numerous large Reed-Sternberg–like cells. Flow cytometry revealed a κ light-chain–restricted CD5 (−), CD23 (−) B-cell population. DNA polymerase chain reaction analysis confirmed the presence of clonal rearrangement of the immunoglobulin heavy-chain gene. Immunohistochemical studies revealed that the large atypical cells were CD30 (+), CD15 (weakly +), CD20 (−), CD45 (−), Pax5 (weakly +), BOB.1 (−), and Oct2 (−), indicating the coexistence of SMZL with cHL. After the chemotherapy, the patient achieved a clinical/radiologic remission, whereas cHL was detected in liver and bone marrow subsequently. The case indicates that both components of lymphoma can present concurrently as a composite form of lymphoma and both need to be treated adequately.     

Immunohistochemical analysis of B-cell lymphoma using tissue microarrays identifies particular phenotypic profiles of B-cell lymphomas

AIMS: To validate the applicability of tissue microarray (TM) in immunohistochemical profiling of B-cell lymphoma and to identify particular phenotypic profiles of B-cell neoplasms. METHODS AND RESULTS: Eighty-two diffuse large B-cell lymphomas (DLBL), 54 follicular lymphomas (FL) and 74 mantle cell lymphomas (MCL) were arrayed. Immunohistochemical stains of TM were compared with immunostains of conventional, formalin-fixed and frozen material sections. Concordant staining results were obtained in more than 88% of cases for CD20, CD3, CD5, CD10, CD23, Bcl-2, IgD, secretory differentiation, p53 and p21 expression. Prognostically relevant hot-spot expression of Ki67 yielded concordant results in 71%. Applying TM for characterization of p27KIP1 expression, both typical and blastoid MCL only rarely showed p27KIP1 expression (9% and 15%), whereas 32% of nodal DLBL were p27KIP1-positive, irrespective of high proliferative activity. Among 22 B-cell lymphomas investigated genetically, a p53 + p21- immunophenotype in >20% of tumour cells correlated with p53 locus deletion. CONCLUSIONS: Lymphoma TM allows for immunohistochemical profiling of human B-cell lymphoma with a comparable accuracy to immunohistochemical studies performed on conventional tissue sections. Nodal DLBLs showed significantly more frequent expression of IgD and p27KIP1 than extranodal DLBL. MCL and DLBL frequently showed aberrant p27KIP1 expression. A p53 + p21- immunophenotype in >20% of tumour cells in B-cell non-Hodgkin's lymphoma correlates with p53 gene deletion.     

CD5-undetected by immunohistochemistry, t(11;14)(q13;q32)-positive conjunctival mantle cell lymphoma: a case report

Most primary ocular adnexal lymphomas are extranodal marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue (MALT). A few cases of ocular adnexal mantle cell lymphomas have been reported in the literature. We present a case of mantle cell lymphoma presenting as conjunctival mass. A 58-year-old man presented with a palpable mass in the left lower tarsal conjunctiva incidentally detected one month previously. Histopathologic examination showed proliferation of monomorphous small-to-medium sized lymphoid cells. On immunohistochemistry, tumor cells were positive for CD20, bcl-2, and cyclin D1, and negative for CD5. PCR analysis for immunoglobulin heavy chain gene rearrangement showed monoclonal B-cell proliferation. t(11;14)(q13;q32), involving the CCND1 and IGH genes, was detected in interphase fluorescent in situ hybridization using formalin-fixed, paraffin-embedded tissue; however, MALT1 gene translocation was not observed. The final diagnosis was mantle cell lymphoma. There was no lymphadenopathy; however, bone marrow involvement of the lymphoma was suspected. The patient has been receiving systemic chemotherapy. This case emphasizes the differential diagnosis of conjunctival mantle cell lymphoma from extranodal marginal zone B-cell lymphomas of MALT regarding the clinical and pathological aspects.     

Anaplastic variant of diffuse large B‐cell lymphoma: Reappraisal as a nodal disease with sinusoidal involvement

Anaplastic variant (av) of diffuse large B‐cell lymphoma (DLBCL) is morphologically defined in the 2017 World Health Organization classification, but still an enigmatic disease in its clinicopathologic distinctiveness, posing the differential diagnostic problem from gray zone lymphoma (GZL) and classic Hodgkin lymphoma (cHL). Thirty‐one cases previously diagnosed as avDLBCL were reassessed. Of these, 27 (87%) and 4 (13%) were node‐based and extranodal diseases, respectively. They were further reclassified into nodal avDLBCL (n = 18), nodal CD30+ DLBCL with T‐cell/histiocyte‐rich large B‐cell lymphoma‐like features (CD30+ DLBCL‐THRLBCL) (n = 6), GZL with features intermediate between DLBCL and cHL (n = 3) and CD30+ extranodal DLBCL, NOS (n = 4). The nodal avDLBCL cases had a sheet‐like proliferation of large cells and/or Hodgkin/Reed‐Sternberg (HRS)‐like cells in 12 (67%) notably with a sinusoidal pattern in 16 (89%). They showed an expression of CD20 and/or CD79a in all and CD30 in 15 of 18. All of them were negative for PD‐L1 on tumor cells, although HRS‐like cells showed negativity or partial loss of other B‐cell markers to varying degrees. The present study highlighted the distinctiveness of the nodal avDLBCL with sinusoidal pattern, but without neoplastic PD‐L1 expression, which provide refined diagnostic criteria for a more precise pathologic and clinical characterization of this disease.     

Diffuse large B-cell lymphoma of the stomach: assessment of microsatellite instability, allelic imbalance, and trisomy of chromosomes 3, 12, and 18.

Several types of genetic aberrations including microsatellite instability (MSI), allelic imbalance (AI), and chromosomal trisomies have been reported in low-grade (LG) mucosa-associated lymphoid tissue (MALT)-type gastric lymphomas. Presence of such genetic alterations could be a discriminator between de novo large cell lymphoma and high-grade (HG) MALT-type lymphoma. We investigated 17 primary gastric large B-cell lymphomas with and without features of MALT-type lymphoma for MSI, AI, and presence of trisomy of chromosomes 3, 12, and 18. We studied resection specimens from 17 primary gastric extranodal diffuse large B-cell lymphomas. Cases classified as HG MALT-type lymphoma, based on either the presence of LG MALT-type lymphoma component in the background (L/H MALT) or large cell lymphoepithelial lesions (HG MALT), and diffuse large B-cell lymphoma (DLBCL-NOS) when no features of MALT were present. MSI was analyzed using fluorescently labeled polymerase chain reaction primers (D3S11, D6S262, D3S1261, D3S1262, D3S1265). Paired tumor and normal DNA samples were amplified, and PCR products were analyzed on a DNA sequencer (ABI PRISM 373XL) with GeneScan (Applied Biosystems, Foster City, CA). MSI was defined as a gain of a novel-length allele compared with the corresponding normal tissue. AI was assessed at locus 3q27 (D3S1262 and D3S1265). The cases were analyzed for the presence of trisomy of chromosomes 3, 12, and 18 using interphase fluorescence in situ hybridization. MSI was detected in 4 out of 15 (27%) cases from which DNA was amplifiable with all primers and all MALT-type lymphomas. In two cases (13%), MSI was present at two loci sufficient to be classified as high-frequency MSI (MSI-H); this was seen exclusively in HG MALT lymphomas (P = 0.04). In the remaining two cases, MSI was detected at a single locus (low-frequency MSI). Allelic imbalance at the locus D3S1262 was detected in 4 out of 17 (24%) cases. It occurred more commonly in stage IE lymphomas when compared with higher stages (P = 0.03), regardless of lymphoma subtype. Trisomy 12 was detected in 3 out of 17 cases (18%) exclusively in stage IE lymphomas (P = 0.08). MSI was uncommon and was found exclusively in MALT-type lymphomas. MSI-H was even less common but occurred in HG MALT lymphomas only. Allelic imbalance at 3q27 (D3S1262) and trisomy 12 were found more commonly in low-stage disease. The latter two findings are in concordance with the recent suggestion that the published variation in gain of chromosomal material in high-grade gastric lymphomas may be related to stage rather than to the subtype of lymphoma. Because of the relatively low frequency of MSI in the high-grade B-cell lymphomas of the stomach, this feature cannot be used to reliably discriminate between the histologic types of extranodal diffuse large B-cell lymphoma.     

A malignant lymphoma with histological features and immunophenotypic profile intermediate between EBV-positive diffuse large B-cell lymphoma and EBV-positive classical Hodgkin lymphoma in a 67-year-old female: a "gray zone" lymphoma associated with Epstein-Barr virus in the elderly

Epstein-Barr virus (EBV) can be associated with both classical Hodgkin lymphoma (cHL) and non-Hodgkin lymphoma of the B-cell type, particularly in immunodeficient patients or elderly individuals. While polymorphic variants of EBV-positive large B-cell lymphoma (EBV+ DLBCL) frequently resemble cHL in morphology, and thereby may cause diagnostic difficulty, a true gray zone lymphoma with overlapping morphological and immunophenotypical features of EBV+ DLBCL and EBV+ cHL has not been reported in the literature. We describe a unique case of an EBV+ malignant lymphoma of B-cell origin with hybrid features of EBV+ DLBCL and EBV+ cHL in a 67-year-old female without an identifiable etiology for immunodeficiency. The biopsy of an enlarged lymph node showed a polymorphic infiltrate containing Reed-Sternberg-like pleomorphic large cells, which were positive for CD30 and CD15. Although CD20 was negative and PAX5 and CD45 were down-regulated, the pleomorphic large cells expressed multiple other B-cell antigens which are characteristically absent in cHL. EBV-encoded RNA hybridization (EBER) studies demonstrated nuclear reactivity in the large cells as well as in the smaller bystander cells. A clonal rearrangement of the immunoglobulin heavy chain gene was also detected by PCR. Although the results of the EBV and genotypic studies suggest this case may be an example of EBV+ DLBCL of the elderly instead of EBV+ cHL, the immunophenotype is strikingly ambiguous. Thus, this case may represent an interface between EBV+ DLBCL and EBV+ cHL.     

Extranodal mantle cell lymphoma mimicking marginal zone cell lymphoma

AIM: We report a case of mantle cell lymphoma masquerading as a marginal zone cell lymphoma. METHODS AND RESULTS: In the initial manifestation in the palatine tonsils, the neoplastic cells were found to grow exclusively within the marginal zones of secondary follicles which showed a preserved mantle zone. The few immunostains performed showed a B-cell phenotype including an immunoglobulin light chain restriction. The extranodal manifestation, the growth pattern, and the immunophenotype led to the diagnosis of an extranodal marginal zone B-cell non-Hodgkin's lymphoma (NHL). The specimen from the relapse occurring 8 months later exhibited diffuse monomorphous cells co-expressing B-cell antigens and CD5, CD43 and cyclin D1, leading to the diagnosis of mantle cell lymphoma. Re-investigation of the initial biopsy revealed that the neoplastic cells within the marginal zones had a mantle cell lymphoma immunophenotype expressing cyclin D1, the immunoglobulin heavy chains IgD and IgM and partly CD5. Both lesions harboured identical clonal immunoglobulin gene rearrangements proving that they represented different manifestations of the same lymphoma. CONCLUSION: This case emphasizes the importance of broad immunohistological investigation of B-cell NHLs involving the marginal zone.     

CD10 and Bcl10 expression in diffuse large B-cell lymphoma: CD10 is a marker of improved prognosis

AIMS: Diffuse large B-cell lymphoma (DLBCL), the most common subtype of non-Hodgkin's lymphoma, is clinically and pathologically heterogeneous. The Bcl10 gene was recently isolated from the breakpoint region of t(1;14)(p22;q32) in mucosa-associated lymphoid tissue (MALT) lymphomas, and is considered to be an apoptosis-associated gene. CD10 is considered to be a marker of follicular centre B-cell differentiation. To assess the clinical significance and roles of CD10 and Bcl10 in DLBCL, we analysed 138 cases, using immunohistochemical methods. METHODS AND RESULTS: CD10 expression was limited to the cytoplasm, whereas Bcl10 expression was detected in the cytoplasm and/or nuclei. CD10 expression was detected in 39 of 138 cases (28.2%), cytoplasmic Bcl10 in 68 cases (49.2%), and nuclear Bcl10 in 34 cases (24.6%). Nuclear Bcl10 was detected in 14 of 28 cases (50%) of extranodal DLBCL, but only 20 of 110 cases (18.2%) of nodal DLBCL. Cytoplasmic Bcl10 was detected in 19 of 28 cases (67.8%) of extranodal DLBCL and 49 of 110 cases (44.5%) of nodal DLBCL. CD10 expression closely correlated with improved survival (68% overall survival (OS) vs. 48% OS), but not with site of disease. A high International Prognostic Index (IPI) was considered to be a poor prognostic factor associated with a shorter OS. CD10 expression was detected in 27 of 84 cases (32.1%) with low-risk IPIs, and in 12 of 54 cases (22.2%) with high-risk IPIs. In the low-risk group, cases expressing CD10 carried a better prognosis than CD10- cases (93% OS vs. 71% OS), whereas this was not the case in the high-risk group (25% vs. 20%). CONCLUSIONS: Bcl10 expression was associated with extranodal DLBCL, but not with prognosis. CD10 expression was closely associated with improved survival, but not with risk as predicted by IPI. Overall, our results suggest that CD10 expression may be useful, in combination with clinical parameters, for determining the prognosis of DLBCL.     

mic2/CD99在经典型霍奇金淋巴瘤H/RS细胞中的表达及与Eber-1/LMP-1相关性的研究

目的： 检测mic2基因与CD99蛋白和Eber-1基因与潜伏膜蛋白-1（LMP1）在经典型霍奇金淋巴瘤（cHL）H/RS细胞中的表达，探讨mic2/CD99表达与Eber-1/LMP-1的相关性。 方法： 采用分子原位杂交和免疫组化技术并结合组织芯片技术检测59例石蜡包埋淋巴瘤组织标本［43例cHL,16例非霍奇金淋巴瘤（NHL）］mic2/CD99和Eber-1/LMP-1的表达，比较分析mic2/CD99在两组中的表达及与Eber-1/LMP-1的关系。 结果： cHL组CD99蛋白表达阳性率为2.3％，mic2基因表达为55.8％，LMP1表达为58.1％，Eber-1表达为53.5％；NHL组CD99蛋白与mic2基因表达高于cHL组（P<0.05）；LMP1和Eber-1的表达低于cHL组（P<0.05）；mic2基因的表达高于CD99蛋白的表达（P<0.05）；Eber-1与LMP1的表达无统计学意义（P>0.05）。CD99蛋白与LMP1的表达呈负相关（P<0.05），各项指标的表达与性别无关。CD99蛋白与LMP1的表达与年龄呈负相关（P<0.05），mic2与Eber-1的表达与年龄无关（P>0.05）。 结论： CD99蛋白在cHL H/RS细胞中低表达，并与LMP1的表达呈负相关。     

B cell lymphoma,unclassifiable, with features intermediate between diffuse large B cell lymphoma and classical hodgkin lymphoma: Diagnosis by fine‐needle aspiration cytology

A 58‐year‐old lady presented with mediastinal lymphadenopathy. A thoracoscopic ultrasound‐guided fine‐needle aspiration showed large atypical epithelioid cells arranged in cohesive sheets and dispersed as single cells with intact cytoplasm amid a background of lymphocytes and histiocytes. A cytological diagnosis of “a malignant neoplasm” was made, raising a broad list of differential diagnoses. A broad panel of immunocytochemical stains performed on the cell block was indicative of a lymphoproliferative disorder, but the immunophenotype was intermediate between diffuse large B cell lymphoma (DLBCL) and classical Hodgkin lymphoma (cHL). Diffuse and strong reactivity to CD20, CD79a, and PAX‐5, and weak reactivity to CD30, was in favor of a DLBCL, or more precisely mediastinal (thymic) large B cell lymphoma (MLBL). However, there were negative staining for LCA, OCT‐2, and BOB‐1 as well as positive staining for EBV‐encoded RNA, which were against a diagnosis of MLBL and raised the possibility of cHL. The absence of RS cells and the typical mileu, the negativity for CD15 and the strong positivity of CD20 and PAX‐5 were against a diagnosis of cHL. On this basis, the diagnosis of “B‐cell lymphoproliferative disorder with features intermediate between DLBCL and cHL” was rendered. The diagnosis was subsequently confirmed on excisional biopsy. This case report demonstrates broad differential diagnoses raised by this diagnostic entity and the importance of an adequate cell block for accurate designation. Diagn. Cytopathol. 2014;42:690–693. © 2013 Wiley Periodicals, Inc.     

BOB.1, CD79a and cyclin E are the most appropriate markers to discriminate classical Hodgkin’s lymphoma from primary mediastinal large B‐cell lymphoma

Hoeller S, Zihler D, Zlobec I, Obermann EC, Pileri SA, Dirnhofer S & Tzankov A
(2010) Histopathology 56, 217–228 BOB.1, CD79a and cyclin E are the most appropriate markers to discriminate classical Hodgkin’s lymphoma from primary mediastinal large B‐cell lymphoma Aims: To clarify which immunohistochemical markers could be helpful in distinguishing between classical Hodgkin’s lymphoma (cHL) and primary mediastinal B‐cell lymphoma (PMBCL) to more narrowly define ‘B‐cell lymphoma, unclassifiable, with features intermediate between diffuse large B‐cell lymphoma and cHL’. Methods and results: Two hundred and 83 cHLs and 51 PMBCLs were analysed on validated tissue microarray platforms with antibodies to BOB.1, CD15, CD20, CD23, CD30, CD79a, cyclin E, LMP‐1, MUM1p, p63 and Oct2. The marker cut‐off scores were calculated using receiver–operating characteristic curves. Markers with the highest positive predictive value for cHL were: CD15, cyclin E, LMP‐1 (all 100%), MUM1p (93%) and CD30 (83%). High sensitivity was achieved only by CD30 (92%) and cyclin E (79%). Nineteen percent of PMBCLs were also positive for CD30, which led to a lower specificity of CD30 as regards cHL (81%) compared with cyclin E (100%). The antibodies with the highest positive predictive value for PMBCL were: CD23 (98%), p63 (96%), BOB.1 (94%) and CD79a (90%), with high sensitivity for BOB.1 (100%), CD79a (89%) and p63 (82%). Conclusions: The use of at least three of the most accurate immunohistochemical markers, cyclin E, CD79a and BOB.1, may be helpful in the differential diagnosis of cHL and PMBCL.     

BCL2 gene abnormalities define distinct clinical subsets of follicular lymphoma

AIMS: Follicular lymphoma (FL) arising primarily in the skin has recently been proposed as a distinct entity on the basis of a low incidence of t(14;18)(q32;q21) and bcl-2 expression, with a very high percentage of patients surviving more than 5 years. However, cases of t(14;18)(q32;q21)-positive primary cutaneous FL (PCFL) and examples of t(14;18)(q32;q21)-negative FL at nodal and other extranodal sites, are well documented. The aim of this study was to test the hypothesis that there is a subtype of FL lacking t(14;18)(q32;q21), which preferentially involves certain sites but is not restricted by anatomical location. METHODS AND RESULTS: A cohort of 47 stage 1 FL was stratified according to the presence or absence of t(14;18)(q32;q21) using conventional cytogenetics, polymerase chain reaction and interphase fluorescence in situ hybridization. Compared with t(14;18)(q32;q21)-positive cases, FL lacking the translocation were less likely to express CD10 or bcl-2 (P<0.01), made up a significantly greater proportion of cases arising at extranodal sites (P<0.001) and had a significantly better overall and disease-specific 5-year survival (P<0.01). CONCLUSIONS: These results support the concept of a subtype of FL lacking t(14;18)(q32;q21), characterized by low-intensity bcl-2 expression, a predilection for extranodal sites, particularly the skin, and a more favourable outcome than t(14;18)(q32;q21)-positive FL.     

Exclusive detection of the t(11;18)(q21;q21) in extranodal marginal zone B cell lymphomas (MZBL) of MALT type in contrast to other MZBL and extranodal large B cell lymphomas

Extranodal mucosa-associated lymphoid tissue (MALT)-type lymphomas and nodal and splenic marginal zone B cell lymphomas (MZBL) share morphological and immunophenotypic features with marginal zone B cells of reactive lymphoid tissues. Although displaying a similar immunophenotype, recent investigations suggest fundamental genetic differences among these subgroups. To determine the prevalence of the t(11;18) in a larger series of MALT-type lymphomas and to investigate a possible occurrence in other lymphomas, we screened 106 non-Hodgkin's lymphomas (NHL) by interphase cytogenetics using yeast artificial chromosome (YAC) probes flanking the breakpoint at 11q21. A signal constellation indicating a disruption in 11q21 and thus pointing to the presence of the t(11;18) was observed in 9 of 33 (27%) low-grade lymphomas of MALT type. The complete absence of t(11;18)-positive cells in 32 primary and secondary extranodal high-grade lymphomas suggests that low-grade lymphomas of MALT type characterized by the t(11;18) are unlikely to transform into high-grade tumors. The absence of tumor cells carrying the t(11;18) in nodal MZBL challenges the assumption that most, if not all, of these tumors represent the nodal manifestation of a so far undetected low-grade lymphoma of MALT type. The t(11;18) was not detected in a single case of 29 splenic MZBL investigated. This observation strengthens the view that splenic MZBL are biologically different from extranodal MZBL of MALT type.     

The role of CD30, CD40 and CD95 in the regulation of proliferation and apoptosis in classical Hodgkin's lymphoma

AIMS: CD30, CD40 and CD95 are members of the tumour necrosis factor receptor superfamily. Ligation to their respective ligands (CD30L, CD40L, CD95L) will generate a diverse set of signalling cascades. We aim to study the expression pattern of CD30, CD40 and CD95 in classical Hodgkin's lymphoma (cHL) and to correlate the expressions with proliferation and apoptosis in the Hodgkin/Reed-Sternberg (H/RS) cells of cHL with or without associated Epstein-Barr virus (EBV) infection. METHODS: A total of 66 cHL cases were retrieved from the archives. Expressions of CD30, CD40, CD95 and proliferation by Ki-67 expression were detected with an immunohistochemical staining method. Apoptosis index was assessed by in situ TUNEL staining technique on 30 randomly selected cases and the presence of EBV was determined by EBER in situ hybridisation. REUSLTS: Expression of CD30, CD40 and CD95 in the H/RS cells was observed in a high proportion of the cases (100, 93.9, 90.5%, respectively). There was no significant association or correlation of the expression of these molecules with the presence of EBV. Expression of CD40 was associated with expression of the proliferation marker Ki-67 (P=0.044), whereas strong (intermediate and high) expression of CD30 showed a significant correlation with proliferation in the EBV-negative cases only (P=0.025). No correlation was observed for the expression of CD30 and CD40 with apoptosis of the H/RS cells. The childhood cases showed weaker CD95 expression in the H/RS cells than the adult cases, and the expression of CD95 was weaker than that of CD40 in the childhood group. CONCLUSIONS: Our results showed that CD30, CD40 and CD95 are highly expressed in the H/RS cells of the majority of cases of cHL. The expression patterns seem to be independent of EBV and do not correlate with apoptosis of the H/RS cells.     

Epstein-Barr virus infection is inversely correlated with the expression of retinoblastoma protein in Reed-Sternberg cells in classic Hodgkin lymphoma

Classic Hodgkin lymphoma (cHL) is characterized by few neoplastic Hodgkin/Reed-Sternberg (H/RS) cells in a background of intense inflammatory infiltrate. Epstein-Barr virus (EBV) has been shown to affect cell cycle and regulation of apoptosis. In total, 82 cases of cHL were studied. Five- micrometer sections were prepared and stained with haematoxylin and eosin and immunohistochemical streptavidin-biotin methods for EBV-LMP-1, pRb, ki-67 and cleaved caspase-3. In-situ hybridization for EBV encoded RNA was used to confirm the detection of EBV in H/RS cells. There were 45 nodular sclerosis, 28 mixed cellularity, 4 lymphocyte-rich, and 5 lymphocyte depletion subtypes in this series of cases. EBV and pRb were detected in 55% (46/82) and 64% (50/82) of the cases respectively. EBV was detected in 78% (25/32) of pRb-negative cases and 81% (29/36) of EBV-negative cases are pRb-positive. A statistically significant inverse relationship was observed between the presence of EBV and expression of pRb (P = 0.001). In conclusion, EBV infection is inversely correlated with pRb in H/RS cells in cHL.