Low stage follicular lymphoma: biologic and clinical characterization according to nodal or extranodal primary origin. Am J Surg Pathol. 2009;33:591-598. [PMID: 19065102 DOI: 10.1097/pas.0b013e31818e6489]

Bridging clinicopathologic features and genetics in follicular lymphoma: Towards enhanced diagnostic accuracy and subtype differentiation

Follicular lymphoma (FL) is a neoplasm that originates from germinal center B cells and typically forms at least a partial follicular pattern. Approximately 85% of FL cases harbor the t(14;18)(q32;q21)/IGH::BCL2 which leads to the overexpression of BCL2. These cases are referred to as classic FL in the current World Health Organization classification [1]. These neoplasms often exhibit hallmark epigenetic deregulation due to recurrent mutations in genes such as KMT2D, CREBBP, and EZH2, with KMT2D and CREBBP considered founding events in FL lymphomagenesis. In contrast, about 15% of FL cases are negative for the t(14;18), which could present diagnostic challenges. These cases may lack the typical genetic markers and require careful pathological and molecular analysis for accurate diagnosis. This review aims to provide an up-to-date pathology resource on FL, focusing on the pathological and molecular characteristics of these neoplasms. We will detail the diagnostic criteria for FL and emphasize the importance of genetic and mutational analyses in accurately characterizing and distinguishing FL subtypes. Furthermore, we will propose methodologies and best practices for the diagnostic work-up of FL to enhance diagnostic accuracy.

Follicular Lymphoma Detected in a Patient Undergoing Mohs Surgery: A Case Report

Mohs surgery is performed by surgeons trained in detecting specific cutaneous malignancies, including basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and dermatofibrosarcoma protuberans (DFSP). Mohs-trained surgeons are typically not holistic pathologists and may, when working in isolation, fail to identify lesions that are not of cutaneous origin. The presence of a second lesion adjacent to the primary lesion is always a possibility. Such a lesion may be misinterpreted as an extension of the identified primary lesion, leading to unnecessary surgery, or it may be overlooked, resulting in a diagnostic failure. There is an advantage to conducting Mohs surgery with the surgeon and histopathologist reviewing the frozen section slides together, as this approach can aid in the identification of rarer diagnoses. Here, we describe the case of a female patient who underwent Mohs micrographic surgery (MMS) for a recurrent BCC located in the left preauricular area and medial helical rim of the pinna. The surgery involved two excisional stages. The first stage showed morphoeic BCC at all levels of all blocks. The second stage showed no BCC but revealed a dense inflammatory infiltrate. On further assessment by the consultant histopathologist, this infiltrate raised suspicion of possible lymphoma. Based on this consensus, no further Mohs excisional surgery was performed, and the surgical defect was closed. Formalin-fixed paraffin-embedded (FFPE) histological assessment and immunohistochemistry confirmed the diagnosis of cutaneous B-cell follicular lymphoma (FL). Thus, the incidental finding on the examination of fresh frozen MMS sections was correctly interpreted by the combined approach of the Mohs surgeon and pathologist, guiding appropriate and timely management for the patient.

Characterization of unique B-cell populations in the circulation of people living with HIV prior to non-Hodgkin lymphoma diagnosis

People living with HIV (PLWH) are at higher risk of developing lymphoma. In this study, we performed cytometry by time-of-flight (CyTOF) on peripheral blood mononuclear cells of cART-naïve HIV+ individuals and cART-naïve HIV+ individuals prior to AIDS-associated non-Hodgkin lymphoma (pre-NHL) diagnosis. Participants were enrolled in the Los Angeles site of the MACS/WIHS Combined Cohort Study (MWCCS). Uniform Manifold Approximation and Projection (UMAP) and unsupervised clustering analysis were performed to identify differences in the expression of B-cell activation markers and/or oncogenic markers associated with lymphomagenesis. CD10+CD27- B cells, CD20+CD27- B cells, and B-cell populations with aberrant features (CD20+CD27+CXCR4+CD71+ B cells and CD20+CXCR4+cMYC+ B cells) were significantly elevated in HIV+ cART-naïve compared to HIV-negative samples. CD20+CD27+CD24+CXCR4+CXCR5+ B cells, CD20+CD27+CD10+CD24+CXCR4+cMYC+ B cells, and a cluster of CD20+CXCR4hiCD27-CD24+CXCR5+CD40+CD4+AICDA+ B cells were significantly elevated in HIV+ pre-NHL (cART-naïve) compared to HIV+ cART-naïve samples. A potentially clonal cluster of CD20+CXCR4+CXCR5+cMYC+AICDA+ B cells and a cluster of germinal center B-cell-like cells (CD19-CD20+CXCR4+Bcl-6+PD-L1+cMYC+) were also found in the circulation of HIV+ pre-NHL (cART-naïve) samples. Moreover, significantly elevated clusters of CD19+CD24hiCD38hi cMYC+ AICDA+ B regulatory cells were identified in HIV+ pre-NHL (cART-naïve) compared to HIV+ cART-naïve samples. The present study identifies unique B-cell subsets in PLWH with potential pre-malignant features that may contribute to the development of pre-tumor B cells in PLWH and that may play a role in lymphomagenesis.

Value of GCET1, HGAL (GCET2), and LMO2 in the Determination of Germinal Center Phenotype in Diffuse Large B-cell Lymphoma

Objective

Diffuse large B-cell lymphoma (DLBCL) is a biologically heterogeneous disease that is classified into germinal center B-cell (GCB) and non-GCB subtypes, which are prognostically different. The Hans algorithm is the most widely used tool based on CD10, BCL6, and MUM1 expression, but some cases with the non-GCB phenotype are still known to be misclassified. In this study, we investigate the extent to which GCET1, HGAL, and LMO2 protein expressions reflect GCB phenotype together with their roles in determining the GCB phenotype of DLBCL and their contributions to the performance of the Hans algorithm.

Materials and Methods

Sixty-five cases of DLBCL-not otherwise specified, 40 cases of follicular lymphoma (FL), and 19 non-GC-derived lymphoma cases were included in this study. The DLBCL cases were grouped as CD10+ (Group A) or only MUM1+ (Group B), and the remaining cases constituted the intermediate group (Group C). GCET1, HGAL, and LMO2 expressions were evaluated.

Results

In the FL group, GCET1, HGAL, and LMO2 were positive in 85%, 77.5%, and 100% of the cases, respectively. Among the non-GC-derived lymphoma cases, all three markers were negative in cases of small lymphocytic lymphoma, plasmablastic lymphoma, peripheral T-cell lymphoma, and anaplastic large cell lymphoma. GCET1 and HGAL were negative in cases of marginal zone lymphoma (MZL) and mantle cell lymphoma (MCL). Two of the 3 MZL and 2 of the 4 MCL cases were positive for LMO2. In the DLBCL group, the number of cases with GCET1, HGAL, and LMO2 positivity was 18 (90%), 17 (85%), and 20 (100%), respectively, in Group A and 0 (0%), 2 (13.3%), and 2 (13.3%), respectively, in Group B. Considering these rates, when the cases in the intermediate group were evaluated, it was concluded that 13 cases typed as non-GCB according to the Hans algorithm may have the GCB phenotype.

Conclusion

GCET1, HGAL, and LMO2 are highly sensitive markers for determining the germinal center cell phenotype and can increase the accuracy of the subclassification of DLBCL cases, especially for cases that are negative for CD10.

Navigating the Heterogeneity of Follicular Lymphoma and its Many Variants: An Updated Approach to Diagnosis and Classification

Follicular lymphoma (FL) is a lymphoid neoplasm composed of follicle center (germinal center) B cells, with varying proportions of centrocytes and centroblasts, that usually has a predominantly follicular architectural pattern. Over the past decade, our understanding of FL has evolved significantly, with new recognition of several recently defined FL variants characterized by distinct clinical presentations, behaviors, genetic alterations, and biology. This manuscript aims to review the heterogeneity of FL and its variants, to provide an updated guide on their diagnosis and classification, and to describe how approaches to the histologic subclassification of classic FL have evolved in current classification schemes.

IGH/BCL2 Status Better Predicts Clinico-Pathological Behavior in Primary Splenic Follicular Lymphoma than Histological Grade and Other Molecular Markers

Splenic lymphoma may be primary or secondary. Primary splenic lymphoma's are rare and usually of follicular cell origin representing <1% of Non-Hodgkin's Lymphoma's. Most are secondary with 35% representing Marginal Cell sub-type with the rest being Diffuse Large B-Cell Lymphoma's. Unlike the uniformly aggressive clinical course of Diffuse Large B-Cell Lymphoma's, biological behavior of Primary Splenic CD10-Positive Small B-Cell Lymphoma/Follicular Lymphoma remains less well defined. We present here a solitary splenic mass confirmed as Primary Splenic CD10-Positive Small B-Cell Lymphoma/Follicular Lymphoma after a diagnostic splenectomy. Biopsy revealed monomorphic small lymphoid cells with low grade mitotic activity. Flow cytometry showed a lambda restricted population of B-Cells displaying dim CD19 and CD10. The cells were negative for CD5, CD11c, and CD103. FISH was negative for IGH/BCL2 fusion unlike nodal Follicular Lymphoma's which are usually positive for this translocation. Evidence from this case and a review of literature support the finding that Primary Splenic CD10-Positive Small B-Cell Lymphoma/Follicular Lymphoma is less likely to have the classic IGH-BCL2 fusion and the associated chromosomal 14;18 translocation. This profile is associated with less aggressive clinical behavior even when histopathology represents a high-grade pattern. In such cases splenectomy alone is adequate for localized disease when negative for IGH/BCL2 fusion regardless of histological grade.

Genomic and microenvironmental landscape of stage I follicular lymphoma, compared with stage III/IV

Although the genomic and immune microenvironmental landscape of follicular lymphoma (FL) has been extensively investigated, little is known about the potential biological differences between stage I and stage III/IV disease. Using next-generation sequencing and immunohistochemistry, 82 FL nodal stage I cases were analyzed and compared with 139 FL stage III/IV nodal cases. Many similarities in mutations, chromosomal copy number aberrations, and microenvironmental cell populations were detected. However, there were also significant differences in microenvironmental and genomic features. CD8+ T cells (P = .02) and STAT6 mutations (false discovery rate [FDR] <0.001) were more frequent in stage I FL. In contrast, programmed cell death protein 1-positive T cells, CD68+/CD163+ macrophages (P < .001), BCL2 translocation (BCL2trl+) (P < .0001), and KMT2D (FDR = 0.003) and CREBBP (FDR = 0.04) mutations were found more frequently in stage III/IV FL. Using clustering, we identified 3 clusters within stage I, and 2 clusters within stage III/IV. The BLC2trl+ stage I cluster was comparable to the BCL2trl+ cluster in stage III/IV. The two BCL2trl- stage I clusters were unique for stage I. One was enriched for CREBBP (95%) and STAT6 (64%) mutations, without BLC6 translocation (BCL6trl), whereas the BCL2trl- stage III/IV cluster contained BCL6trl (64%) with fewer CREBBP (45%) and STAT6 (9%) mutations. The other BCL2trl- stage I cluster was relatively heterogeneous with more copy number aberrations and linker histone mutations. This exploratory study shows that stage I FL is genetically heterogeneous with different underlying oncogenic pathways. Stage I FL BCL2trl- is likely STAT6 driven, whereas BCL2trl- stage III/IV appears to be more BCL6trl driven.

Primary follicular lymphoma of colon: A case series and review of literature

Follicular lymphoma of the colon is rare, accounting for 1% to 2% of cases in the gastrointestinal tract. Despite the absence of randomized clinical trials, NCCN stage III and IV colonic follicular lymphomas are routinely treated with chemotherapy with good clinical response. We present 2 cases of advanced stage follicular lymphoma of colon that were effectively treated with bendamustine-based chemotherapy regimens.

The molecular landscape and other distinctive features of primary cutaneous follicle center lymphoma

Primary cutaneous follicle center lymphoma (PCFCL) is distinguished from other follicular lymphomas (FLs) based on its clinicopathologic features including diminished CD10 and frequent lack of BCL2 rearrangements (R). Whether newer germinal center-associated markers would also be less commonly expressed and whether mutational studies would support its segregation from classic FL and FL subsets, including those which also typically lack BCL2R, are uncertain. To address these questions, 22 PCFCLs were stained for myocyte enhancer factor 2B (MEF2B) and human germinal center-associated lymphoma (HGAL), and targeted next-generation sequencing was performed with results compared to a meta-analysis of FL, pediatric-type FL (PTFL), low stage FL (LSFL) and other FL subsets. Selected fluorescence in situ hybridization studies were also performed. Although 27% of cases lacked CD10, all tested were MEF2B+ and HGAL+. The most common somatic mutations in the 12 to 19 analyzable PCFCL were TNFRSF14 (40%, plus 10% with 1p36 deletions), followed by CREBBP, TNFAIP3, KMT2D, SOCS1, EP300, STAT6, and FOXO1 (17-25%). Three of the most commonly mutated genes in FL (KMT2D, CREBBP, and BCL2) were significantly less commonly mutated in PCFCL than in FL, and TNFAIP was more commonly mutated with no difference for TNFRSF14 between PCFCL and FL or PTFL. CREBBP was also less frequently mutated than in LSFL but more frequently mutated than in PTFL. MAP2K1 mutations were much more common in PTFL (44% versus 0%). Two of 22 of the PCFCL had a BCL2 rearrangement and zero of 12 had a BCL6 rearrangement. These findings, while showing well-recognized and new shared features between PCFCL and other FL, highlight a distinctive mutational profile further supporting its recognition as a distinct entity.

Early Stage Extranodal Follicular Lymphoma: Characteristics, Management, and Outcomes

INTRODUCTION

Extranodal follicular lymphoma (E-FL) is a rare entity that has distinct characteristics and outcomes compared with nodal follicular lymphoma.

PATIENTS AND METHODS

This cohort comprised 37 patients with stages I/II E-FL, diagnosed from 2003 to 2013. Outcomes included progression-free survival (PFS), and overall survival (OS). Survival outcomes were calculated using Kaplan-Meier methods.

RESULTS

Median age was 60 years (range, 37-84 years). Disease was stage I in 29 (78.4%). The Follicular Lymphoma International Prognostic Index score was 0 to 1 in 31 (83.8%), 2 in 2 (5.4%), 3 in 1 (2.7%), and missing in 3 (8.1%). Sites of involvement included the gastrointestinal (GI) tract in 22 (59.5%), and non-GI sites in 15 (40.5%). Initial management consisted of chemotherapy (CHT) alone in 21 (56.8%), radiation therapy (RT) alone in 2 patients (5.4%), RT and rituximab in 1 (2.7%), CHT and RT in 7 (18.9%), and observation in 6 (16.2%). RT was to a median dose of 30.6 Gy (range, 23.4-44.0 Gy). At a median follow-up of 69 months (range, 8-157 months), 5-year PFS and OS were 70.4% and 94.4%, respectively. Although the 5-year PFS of those observed was worse than for those who received therapy (33.3% vs. 77.6%; P = .011), that did not translate into an OS difference. Patients who received RT as part of upfront management had a 100% local control (LC) rate and a trend toward improved 5-year PFS (90% vs. 62.2%; P = .067).

CONCLUSION

Early stage E-FL is an indolent disease and is associated with excellent OS. Treatment strategies should be individualized with RT prioritized when LC is a significant goal.

Colorectal follicular lymphoma: A case report

RATIONALE

Considering the low incidence of colorectal follicular lymphoma (FL) and its clinical features in endoscopic views, only a few studies have described the pathological diagnosis and treatment of this disease. This study aimed to reveal the overall process of clinical diagnosis and treatment of colorectal FL by conducting a case review.

PATIENT CONCERNS

A 27-year-old female presented to our department because of "severe bloody stool" lasting for more than 1 month. Her primary symptom was melena. Colonoscopy revealed widespread flat polyps with various immunophenotypes (CD10+, BCL2+, BCL6+, cyclin D1-, CD5-) in the colorectal area.

DIAGNOSIS

In accordance with manifestations on positron emission tomography-computed tomography (PET/CT), the patient was diagnosed with stage IV colorectal FL.

INTERVENTIONS

PET/CT reexamination after 2 courses of rituximab, cyclophosphamide, liposomal doxorubicin, vincristine sulfate, and hydroprednisone (R-CHOP) regimen and 3 courses of R-CHOP plus etoposide regimen for chemotherapy indicated a significant reduction in tumor burden. Subsequently, rituximab was administered alone in 2 treatment courses.

OUTCOMES

Lesions on PET/CT disappeared after reexamination. No recurrence was observed within the 12-month follow-up period.

LESSONS

Colorectal FL is a rare disease with an inert clinical course and is common in the ileocecal area. Endoscopic views show multiple polyps. Interventional treatment is usually provided after observation of clinical symptoms or during disease progression. The disease has a relatively good prognosis.

Primary Cutaneous Follicle Center Lymphomas Expressing BCL2 Protein Frequently Harbor BCL2 Gene Break and May Present 1p36 Deletion: A Study of 20 Cases

The classification of cutaneous follicular lymphoma (CFL) into primary cutaneous follicle center lymphoma (PCFCL) or secondary cutaneous follicular lymphoma (SCFL) is challenging. SCFL is suspected when tumor cells express BCL2 protein, reflecting a BCL2 translocation. However, BCL2 expression is difficult to assess in CFLs because of numerous BCL2+ reactive T cells. To investigate these issues and to further characterize PCFCL, we studied a series of 25 CFLs without any extracutaneous disease at diagnosis, selected on the basis of BCL2 protein expression using 2 BCL2 antibodies (clones 124 and E17) and BOB1/BCL2 double immunostaining. All cases were studied using interphase fluorescence in situ hybridization with BCL2, BCL6, IGH, IGK, IGL breakapart, IGH-BCL2 fusion, and 1p36/1q25 dual-color probes. Nineteen CFLs were BCL2 positive, and 6 were negative. After a medium follow-up of 24 (6 to 96) months, 5 cases were reclassified as SCFL and were excluded from a part of our analyses. Among BCL2+ PCFCLs, 60% (9/15) demonstrated a BCL2 break. BCL2-break-positive cases had a tendency to occur in the head and neck and showed the classical phenotype of nodal follicular lymphoma (CD10+, BCL6+, BCL2+, STMN+) compared with BCL2-break-negative PCFCLs. Del 1p36 was observed in 1 PCFCL. No significant clinical differences were observed between BCL2+ or BCL2- PCFCL. In conclusion, we show that a subset of PCFCLs harbor similar genetic alterations, as observed in nodal follicular lymphomas, including BCL2 breaks and 1p36 deletion. As BCL2 protein expression is usually associated with the presence of a BCL2 translocation, fluorescence in situ hybridization should be performed to confirm this hypothesis.

Follicular lymphoma of the ocular adnexal region: a nation-based study

PURPOSE

To characterize the clinicopathological features of follicular lymphoma of the ocular adnexal region.

METHODS

Retrospective nation-based study of Danish patients with ocular adnexal follicular lymphoma from January 1st 1980 through December 31st 2009.

RESULTS

Twenty-four patients with ocular adnexal follicular lymphoma were identified. Fourteen (58%) of the patients were females. The median age was 63 years (range: 42-96 years). Eleven (46%) of the patients had primary ocular adnexal lymphoma, seven (29%) had an ocular adnexal lesion in conjunction with a concurrent systemic lymphoma and six patients (25%) presented with an ocular adnexal relapse. The most frequently affected sites were the lacrimal gland (38%) and the orbit (33%). Thirteen patients (54%) presented with Ann Arbor stage IE lymphoma, four (17%) had stage IIE, two patients (8%) stage IIIE, and five patients (21%) had stage IV lymphoma. Radiotherapy was primarily used in patients with primary lymphoma and those with a stage IE/IIE relapse (82%), while stage IIIE/IV lymphomas most frequently received alkylating chemotherapy (67%). Complete remission was observed in 19 of the patients (79%), but of these 11(58%) had a relapse. The 10-year overall survival for the entire cohort was 59%. The translocation t(14;18) was detected in 16 patients (16/24, 76%). Recurrence was only observed in patients with the t(14;18) (p=0.05, log-rank).

CONCLUSIONS

Ocular adnexal follicular lymphoma is more commonly found in elderly female patients. The lacrimal gland is relatively frequently involved. Radiotherapy is the treatment of choice for localized ocular adnexal follicular lymphoma providing a favourable prognosis for majority of patients.

TLR2-activated B cells are phenotypically similar to the abnormal circulating B cells seen preceding the diagnosis of AIDS-related NHL diagnosis

BACKGROUND

AIDS-related non-Hodgkin lymphoma (AIDS-NHL) is a common AIDS-defining cancer. Prior studies suggest that chronic B-cell activation precedes AIDS-NHL diagnosis. Activation of B cells by multiple factors, including Toll-like receptor (TLR) signaling, leads to the expression of activation-induced cytidine deaminase (AID), a DNA mutating molecule that can contribute to oncogene translocations/mutations, leading to NHL. The goal of this study was to determine whether surface markers expressed on activated and/or germinal center B cells, and AID expression, were elevated on circulating B cells preceding AIDS-NHL and to determine if TLR signaling contributes to this activated B-cell phenotype.

METHODS

Stored viable peripheral blood mononuclear cell specimens, obtained before AIDS-NHL diagnosis, were assessed by multicolor flow cytometry. Additionally, B cells isolated from peripheral blood mononuclear cell were exposed to TLR ligands in vitro, after which B-cell phenotype was assessed by flow cytometry.

RESULTS

An elevated fraction of B cells expressing CD10, CD71, or CD86 was seen in those who went on to develop AIDS-NHL. AID expression was detected in some who developed AIDS-NHL, but not in HIV+ or HIV- controls. TLR2-stimulated purified B cells exhibited the activated B-cell phenotype observed in HIV+ subjects before AIDS-NHL diagnosis.

CONCLUSIONS

These results indicate that an elevated fraction of B cells display an activated/germinal center phenotype in those HIV+ subjects who go on to develop AIDS-NHL and suggest that TLR2-mediated activation may play a role in HIV infection-associated B-cell activation, potentially contributing to the genesis of AIDS-NHL.

Oral follicular lymphomas. A short report of 8 cases with assessment of the IGH/BCL2 gene fusion with fluorescence in situ hybridization

OBJECTIVE

To present the clinicopathologic features and confirm the presence of the IGH/BCL2 gene fusion in an oral follicular lymphoma (OFL) series.

STUDY DESIGN

Cases of OFLs were retrieved from a data base of non-Hodgkin lymphomas (NHL). Fluorescence in situ hybridization (FISH) was performed to confirm the IGH/BCL2 fusion.

RESULTS

Eight (8.7%) of 92 NHL were OFLs. Six (75%) patients were male and two female (mean age: 73.4 ± 14.8). The most frequent site was the palate. Five of the 8 patients are alive and without disease. Five (three grade 1 and two grade 2) of six successfully hybridized cases revealed the IGH/BCL2 gene fusion. The sixth case, a grade 3 follicular lymphoma (FL), demonstrated multiple BCL2 signals without IGH/BCL2 fusion.

CONCLUSIONS

OFLs exhibit an indolent clinical behavior. In the present study, 5/6 cases in which FISH was successful had an IGH/BCL2 fusion as would result from the t(14; 18)(q32; q21) translocation commonly seen in FL of extraoral sites.

Gastrointestinal B-cell lymphomas: From understanding B-cell physiology to classification and molecular pathology

The gut is the most common extranodal site where lymphomas arise. Although all histological lymphoma types may develop in the gut, small and large B-cell lymphomas predominate. The sometimes unexpected finding of a lymphoid lesion in an endoscopic biopsy of the gut may challenge both the clinician (who is not always familiar with lymphoma pathogenesis) and the pathologist (who will often be hampered in his/her diagnostic skill by the limited amount of available tissue). Moreover, the past 2 decades have spawned an avalanche of new data that encompasses both the function of the reactive B-cell as well as the pathogenic pathways that lead to its neoplastic counterpart, the B-cell lymphoma. Therefore, this review aims to offer clinicians an overview of B-cell lymphomas in the gut, and their pertinent molecular features that have led to new insights regarding lymphomagenesis. It addresses the question as how to incorporate all presently available information on normal and neoplastic B-cell differentiation, and how this knowledge can be applied in daily clinical practice (e.g., diagnostic tools, prognostic biomarkers or therapeutic targets) to optimalise the managment of this heterogeneous group of neoplasms.

DNA methylation analysis of ALOX12 and GSTM1 in acute myeloid leukaemia identifies prognostically significant groups

To determine the role of DNA methylation in the progression of acute myeloid leukaemia (AML), we analysed the methylation status of ALOX12, GSTM1, HS3ST2 and FZD9 in 127 AML patients. Aberrant methylation of ALOX12 was associated with the subcategory AML with myelodysplasia-related changes (P = 0·0439) and specifically with megakaryocytic dysplasia (P = 0·0003). An association between HS3ST2 and AML patients with favourable cytogenetic risk was identified (P = 0·0469). In univariate and multivariate analysis, methylation of GSTM1 was associated with worse overall survival (OS) and disease-free survival (DFS), with hazard ratios of 2·57 and 1·86, respectively. Furthermore, the significance of methylation of GSTM1 in predicting poor prognosis was maintained within the subcategories of AML not otherwise specified (NOS), AML with intermediate cytogenetic risk and normal karyotype AML. Finally, patients with both GSTM1 and ALOX12 methylated, demonstrated worse outcomes when all AML patients were assessed (OS; P = 0·000411) as well as within AML NOS (DFS; P = 0·0023), AML with intermediate cytogenetic risk (OS; P = 0·0104) and normal karyotype AML (OS; P = 0·00636). This study implicates methylation of specific genes in the classification and prognostication of AML and suggests that the morphological feature of multilineage dysplasia may be a surrogate marker of gene methylation in at least a subset of AML cases.

Comparison of germinal center markers CD10, BCL6 and human germinal center-associated lymphoma (HGAL) in follicular lymphomas

Background

Recently, human germinal center-associated lymphoma (HGAL) gene protein has been proposed as an adjunctive follicular marker to CD10 and BCL6.

Methods

Our aim was to evaluate immunoreactivity for HGAL in 82 cases of follicular lymphomas (FLs) - 67 nodal, 5 cutaneous and 10 transformed - which were all analysed histologically, by immunohistochemistry and PCR.

Results

Immunostaining for HGAL was more frequently positive (97.6%) than that for BCL6 (92.7%) and CD10 (90.2%) in FLs; the cases negative for bcl6 and/or for CD10 were all positive for HGAL, whereas the two cases negative for HGAL were positive with BCL6; no difference in HGAL immunostaining was found among different malignant subtypes or grades.

Conclusions

Therefore, HGAL can be used in the immunostaining of FLs as the most sensitive germinal center (GC)-marker; when applied alone, it would half the immunostaining costs, reserving the use of the other two markers only to HGAL-negative cases.

Translocation t(14;18)/IGH-BCL2 in gastrointestinal follicular lymphoma: correlation with clinicopathologic features in 48 patients

BACKGROUND

Chromosomal translocation t(14;18)(q32;q21) involving the immunoglobulin heavy chain gene (IGH) and the BCL2 gene (t[14;18][q32;q21]/IGH-BCL2) is present in 60% to 90% of nodal follicular lymphomas. To the authors' knowledge, the prevalence and clinical significance of this translocation have not been examined previously in gastrointestinal follicular lymphomas.

METHODS

Clinicopathologic and molecular features were investigated in 48 patients who had gastrointestinal follicular lymphoma. The site of involvement was the duodenum in 54% of patients, the jejunum in 52%, the ileum in 52%, the stomach in 29%, and the colorectum in 15%. The presence of the t(14;18)/IGH-BCL2 translocation was detected by interphase fluorescence in situ hybridization.

RESULTS

Treatment modalities included surgical resection (n = 16), rituximab plus chemotherapy (n = 13), rituximab alone (n = 6), antibiotics (n = 5), and watchful waiting (n = 8). Complete remission (CR) of lymphoma was achieved in 31 patients (65%). The overall survival and event-free survival rates after 5 years were 93% and 68%, respectively. The t(14;18)/IGH-BCL2 was detected in 39 patients (81%). The involvement of multiple sites (69% vs 0%), manifestation of the lymphomatous polyposis type (72% vs 22%), and histologic grade 1 or 2 tumors (92% vs 56%) were more frequent in the t(14;18)-positive group than in the negative group. In addition, the CR rate was lower in the t(14;18)-positive group than in the negative group (56% vs 100%; P = .0179), and a trend was observed toward poorer event-free survival in the positive group (P = .089).

CONCLUSIONS

The t(14;18)/IGH-BCL2 chromosomal translocation occurred frequently in gastrointestinal follicular lymphomas. The current results indicated that this translocation may be a predictor of an adverse clinical course.

Immunoarchitectural patterns in follicular lymphoma: efficacy of HGAL and LMO2 in the detection of the interfollicular and diffuse components

Follicular lymphoma (FL) can exhibit variant histologic patterns that can lead to confusion with other B-cell lymphomas and reactive conditions. Diagnostic markers such as CD10 and BCL2 may be difficult to interpret in variant FL patterns, and are often diminished or absent in the interfollicular and diffuse components. We evaluated 2 recently characterized germinal center B-cell markers, human germinal center associated lymphoma (HGAL), and LIM-only transcription factor 2 (LMO2), in 127 FL patient biopsies (94 nodal, 33 extranodal), and correlated the findings with histologic pattern, cellular composition, grade, and additional immunostains (CD20, CD3, CD21, CD10, BCL2, and BCL6). Architectural patterns included predominantly follicular (75%) and follicular and diffuse components (25%); 10 cases showed marginal zone differentiation and 3 were floral variants. Eighty-nine cases were low grade (38 grade 1; 51 grade 2) and 38 were grade 3 (29 grade 3A and 9 grade 3B). HGAL had the highest overall sensitivity of detecting FL and was superior in detecting the interfollicular and diffuse components compared with BCL2, LMO2, CD10, and BCL6. All 28 cases that lacked CD10, expressed HGAL, and the majority also expressed LMO2. Our results show that HGAL and LMO2 are sensitive markers for FL diagnosis. The addition of HGAL and LMO2 to the immunohistologic panel is beneficial in the work-up of nodal and extranodal B-cell lymphomas and the efficacy of HGAL in detecting the follicular, interfollicular and diffuse components of FL is of particular value in the setting of variant immunoarchitectural patterns.

Incidence of extranodal non-Hodgkin lymphomas among whites, blacks, and Asians/Pacific Islanders in the United States: anatomic site and histology differences

BACKGROUND

Extranodal non-Hodgkin lymphoma (NHL) accounts for much of the increase in NHL incidence in the past three decades in the United States, but its descriptive epidemiology is scarce in the literature.

METHODS

Incidence data for the years 1999-2003 were from 38 population-based cancer registries, covering 82% of US population. We grouped anatomic sites of extranodal NHLs according to the Surveillance, Epidemiology, and End Results (SEER) site recodes, and histology subtypes according to the nested classification of lymphoid neoplasms developed by the Pathology Working Group of the International Lymphoma Epidemiology Consortium.

RESULTS

Blacks and Asians/Pacific Islanders (APIs) experienced incidence rates about the same as or lower than whites' for B-cell extranodal NHL as a whole and most of its histologic subtypes. The significant exceptions are: API men had a 40% higher rate of marginal zone lymphoma (MZL) than white men, and API women had a 12% higher rate of diffuse large B-cell lymphoma (DLBCL) than white women. The rates of all T-cell extranodal NHLs combined and peripheral T-cell lymphoma (PTCL) among black women exceeded those of white women by 46% and 18%, respectively. Blacks also had higher rates of mycosis fungoides (MF) than whites (28% higher for men and 99% higher for women). The most common sites of extranodal NHL are stomach, skin, and oral cavity and pharynx. Compared with whites, blacks had either lower or similar incidence of NHL for all sites except skin for women while APIs had higher rates of NHL of the stomach, nose/nasal cavity/middle ear, colorectum (women only), and brain (men only). Age was associated with race- and sex-specific differences in histology-specific incidence rates.

CONCLUSION

While blacks and APIs had lower or similar overall incidence rates for extranodal NHL, they experienced excessive rates in some subtypes. Blacks had higher rates of the two most common types of T-cell extranodal NHL and APIs had higher rate of the two common types of B-cell types than whites. Distinct race-specific patterns in histology- and site-specific incidence of extranodal NHL may implicate racial differences in risk factor exposure and/or genetic predisposition.