[Clinicopathological features of follicular lymphoma in children].

Objective: To investigate the clinicopathologic features of follicular lymphoma (FL) in children. Methods: One female and one male patients with FL diagnosed in the First College of Clinical Medical Science, China Three Gorges University and Beijing Friendship Hospital of the Capital University of Medical Science in February 2016 and June 2015 were studied by HE immunohistochemistry, EBER in situ hybridization, IgH and IgK gene rearrangement analysis and IRF4 fusion gene detection. Results: The two patients' age were 6.3 and 12 years, respectively. The lesions involved head and neck lymph nodes with duration of more than 2 months. Histopathologically, the lesions consisted of nodular proliferation of lymphoid follicles with diffuse distribution of large cells. Starry sky phenomenon was seen in one of the two cases. Immunohistochemistry showed that one case was positive for bcl-2 and MUM1, but negative for bcl-6 and CD10. Ki-67 index was>50% and oligoclonal IgK rearrangement was observed. The second case showed positivity for bcl-6, and CD10 but negative for bcl-2. Ki-67 index was>50% and clonal IgH FR1-JH and IgH FR2-JH rearrangements were detected. Both cases showed no evidence of IRF4 gene fusion. Conclusions: Childhood FL is a rare B-cell lymphoma with characteristic features and high-grade histomorphology. However, its immunophenotype and molecular genetic characteristics are divergent.

J chain and myocyte enhancer factor 2B are useful in differentiating classical Hodgkin lymphoma from nodular lymphocyte predominant Hodgkin lymphoma and primary mediastinal large B-cell lymphoma.

Although most classical Hodgkin lymphomas (CHLs) are easily distinguished from nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) and primary mediastinal large B-cell lymphoma (PMBL), cases with significant CD20 expression cause diagnostic confusion. Although the absence of OCT-2 and BOB.1 are useful in these circumstances, a variable proportion of CHLs are positive for these antigens. We investigated the utility of J chain and myocyte enhancer factor 2B (MEF2B) in the diagnosis of CHL; NLPHL; PMBL; T-cell/histiocyte-rich large B-cell lymphoma (TCRLBL); and B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and CHL, compared with OCT-2 and BOB.1. J chain and MEF2B highlighted lymphocyte predominant (LP) cells in 20/20 (100%) NLPHLs and were negative in 43/43 (100%) CHLs. Fourteen of 15 (93%) PMBLs and 4/4 (100%) TCRLBLs were MEF2B positive, whereas 67% of PMBLs and 50% of TCRLBLs were J chain positive. Three of 3 B-cell lymphomas, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and CHL, were negative for J chain and MEF2B. J chain and MEF2B were 100% sensitive and specific for NLPHL versus CHL. MEF2B was 100% sensitive and 98% specific for PMBL versus CHL. Whereas loss of OCT-2 and/or BOB.1 expression had a sensitivity of only 86% and specificity of 100% for CHL versus NLPHL, PMBL, and TCRLBL, lack of both J chain and MEF2B expression was 100% sensitive and 97% specific. J chain and MEF2B are highly sensitive and specific markers of NLPHL versus CHL; are particularly useful in highlighting LP cells; and, with rare exception, are of greater utility than OCT-2 and BOB.1 in differentiating CHL from NLPHL and other large B-cell lymphomas.

Characteristics and clinical implications of reactive germinal centers in the bone marrow.

Reactive germinal centers (GCs) in the bone marrow (BM) have been described in patients with autoimmune disorders, infections, malignancies, and following certain drug therapies, or as an isolated finding without obvious underlying disease. In this study, we describe the clinical conditions in which reactive GCs occur in BM samples, and their topography and accompanying laboratory and ancillary findings in the setting of a cancer center. We identified 32 BM specimens with reactive GCs with an estimated frequency less than 0.02% over a 12-year period. Fifteen (46.9%) BM specimens had concurrent hematolymphoid neoplasms: most often a variety of small B-cell lymphomas, but also myelodysplastic syndromes. One (3.1%) case was involved by metastatic melanoma. Isolated reactive GCs were observed in 16 (50%) patients. Most BM specimens (n = 25; 78.1%) showed only one reactive GC with a size ranging from 20 to 500 µm, and most GCs (29/32) were nonparatrabecular. GCs were positive for CD10 and BCL6, and were negative for BCL2. CD3 and CD5 demonstrated T cells surrounding the GC and CD21, and CD23 highlighted follicular dendritic cells. Reactive GCs are uncommon and can be seen in association with hematolymphoid and other types of neoplasms or as an isolated finding. Reactive GCs are usually located in a nonparatrabecular distribution. A panel of immunohistochemical stains is useful to confirm the nonneoplastic nature of these GCs to avoid misdiagnosis as lymphoma or as histologic evidence of transformation in a patient with small B-cell lymphoma in the bone marrow.

Cutaneous B-cell lymphomas - pathogenesis, diagnostic workup, and therapy.

Cutaneous B-cell lymphomas (CBCLs) comprise a group of mature lymphoproliferative B-cell disorders that primarily affect the skin. Characterized by great biological and clinical variability among its various subtypes, CBCLs fundamentally differ from primary nodal or systemic B-cell lymphomas. Given their uncomplicated course and excellent prognosis, lymphoma classifications rank primary cutaneous marginal zone lymphoma (PCMZL) and primary cutaneous follicle center lymphoma (PCFCL) as indolent CBCLs. By contrast, diffuse large B-cell lymphoma, leg type (DLBCL-LT) in particular, represent more aggressive lymphoma variants associated with a poorer prognosis. Therapeutic decisions and diagnostic procedures are based on the exact histological and immunohistochemical classification as well as the exclusion of systemic involvement and thus differentiation from nodal and systemic lymphomas. In this context, the diagnostic workup should also include molecular biology methods. Primary therapeutic options for indolent CBCL lesions include surgery and radiation therapy, as well as systemic treatment with rituximab (anti-CD20 antibody) in case of dissemination. More aggressive CBCLs usually require a combination of rituximab and polychemotherapy, primarily the CHOP regimen or modifications thereof. Given that the pathogenesis and biology of CBCLs has not been conclusively elucidated, and given the limited therapeutic armamentarium available, there is great need for comprehensive research, especially with respect to DLBCL-LT.

Pathology of Extranodal Lymphoma.

An overview of the pathology of extranodal lymphoma is presented. The emphasis of this presentation is on the classification system of extranodal lymphomas, including both B-cell and T-cell lymphomas, based on their morphology, phenotype, and molecular alterations.

B-cell receptor signaling in chronic lymphocytic leukemia and other B-cell malignancies.

B-cell receptor (BCR) signaling has emerged as a key pathway for the expansion of neoplastic B-cell clones in several B-cell malignancies. The mechanisms that activate BCR signaling differ substantially among subtypes of B-cell lymphoma and leukemia. These include BCR stimulation by foreign or self-antigens, or the acquisition of mutations in components of the BCR pathway that result in autonomous or enhanced antigen-induced BCR signaling. Targeting BCR signaling with selective inhibitors of the BCR-associated kinases Bruton's tyrosine kinase, spleen tyrosine kinase, and phosphoinositide 3-kinase delta induces high response rates in patients with chronic lymphocytic leukemia, mantle cell lymphoma, Waldenström macroglobulinemia, and diffuse large B-cell lymphoma of the activated B-cell-like subtype and is currently transforming the therapeutic landscape in these diseases. Here we review the mechanisms of BCR activation that govern growth and survival of malignant B cells. We also summarize recent clinical trials of BCR inhibitors, with a focus on the most clinically advanced agents.

Evaluation of the diagnostic and prognostic value of PDL1 expression in Hodgkin and B-cell lymphomas.

Activation of the programmed death 1 (PD1)/PD1 ligand (PDL1) pathway is important for tumor cells to escape from immune control. The clinical efficacy of therapeutic modulation of the PD1-PDL1 pathway has been recently shown in classical Hodgkin lymphoma (cHL), but little is known about the frequency and diagnostic and prognostic importance of PDL1 expression in lymphomas. The available anti-PDL1 antibody clones E1L3N and SP142 were compared, and a large cohort of Hodgkin lymphomas (n=280) and B-cell lymphomas (n=619) was examined for PDL1 using E1L3N. The results were correlated with the expression of other phenotypic markers, interphase fluorescence in situ hybridization data of the 9p24.1 region (PDL1 locus), and the clinical outcome. PDL1 was expressed on more than 5% of tumor cells in 70% of cHL, 54% of nodular lymphocyte-predominant Hodgkin lymphoma, and 35% of primary mediastinal B-cell lymphomas; in the latter, PDL1 expression correlated with PDL1 gains (ρ=0.573). PDL1 was expressed in 31% of primary diffuse large B-cell lymphomas (DLBCLs), whereas most other entities did not express PDL1. In cHL, expression of PDL1 correlated with increased numbers of granzyme+ T cells (ρ=0.251) and CD68+ macrophages (ρ=0.221) but with decreased numbers of FoxP3+ T cells (ρ=0.145). In activated B-cell-like DLBCL, PDL1 positively correlated with PD1+ T cells, whereas an inverse correlation with FoxP3+ T cells was seen in the germinal center B-cell-like DLBCL. PDL1 expression can be diagnostically valuable in some gray zones around DLBCL and cHL; it identifies an "immune escape" cluster of cHL and activated B-cell-like DLBCL with increased granzyme+ and PD1+ T cells and macrophages and decreased regulatory T cells.

The role of the Chaperonin containing t-complex polypeptide 1, subunit 8 (CCT8) in B-cell non-Hodgkin's lymphoma.

The chaperonin containing t-complex polypeptide 1 (CCT) is known to mediate folding of proteins. CCT, subunit 8 (CCT8), is the θ subunit of CCT complex chaperonin. CCT8 has been reported to be dysregulated in several tumor tissues. In this study, we investigated the role of CCT8 in B-cell non-Hodgkin's lymphoma (NHL). Clinically, the expression levels of CCT8 in reactive lymphoid hyperplasia (RLH) and B-cell NHL specimens were investigated using immunohistochemical analysis. We found that CCT8 was highly expressed in proliferating germinal center cells compared with the quiescent cells of the follicular mantle zone. Furthermore, CCT8 was highly expressed in progressive lymphomas than in indolent lymphomas. Kaplan-Meier curve showed that high expression of CCT8 was significantly associated with shorter overall survival in patients with diffuse large B-cell lymphoma. Moreover, we demonstrated that CCT8 could promote the proliferation of B-cell NHL cells. In addition, we found that CCT8 could accelerate the G1/S transition in B-cell NHL. Finally, we demonstrated that overexpression of CCT8 could reverse cell adhesion-mediated drug resistance (CAM-DR) phenotype. Our study may shed new insights into the important role of CCT8 in cancer development.

NOTCH1, TP53, and MAP2K1 Mutations in Splenic Diffuse Red Pulp Small B-cell Lymphoma Are Associated With Progressive Disease.

Splenic diffuse red pulp small B-cell lymphoma (SDRPL) is considered an indolent neoplasm and its pathogenesis is not well known. We investigated the molecular characteristics of 19 SDRPL patients, 5 of them with progressive disease. IGHV genes were mutated in 9/13 (69%). Cytogenetic and molecular studies identified complex karyotypes in 2 cases, and IGH rearrangements in 3, with PAX5 and potentially TCL1 as partners in each one of them. Copy number arrays showed aberrations in 69% of the tumors, including recurrent losses of 10q23, 14q31-q32, and 17p13 in 3, and 9p21 in 2 cases. Deletion of 7q31.3-q32.3 was present in only 1 case and no trisomies 3 or 18 were detected. NOTCH1 and MAP2K1 were mutated in 2 cases each, whereas BRAF, TP53, and SF3B1 were mutated each in single cases. No mutations were found in NOTCH2 or MYD88. Four of the 5 patients with aggressive disease had mutations in NOTCH1 (2 cases), TP53 (1 case), and MAP2K1 (1 case). The progression-free survival of patients with mutated genes was significantly shorter than in the unmutated (P=0.011). These findings show that SDRPL share some mutated genes but not chromosomal alterations, with other splenic lymphomas, that may confer a more aggressive behavior.

Controlled Multi-functionalization Facilitates Targeted Delivery of Nanoparticles to Cancer Cells.

A major objective of nanomedicine is to combine in a controlled manner multiple functional entities into a single nanoscale device to target particles with great spatial precision, thereby increasing the selectivity and potency of therapeutic drugs. A multifunctional nanoparticle is described for controlled conjugation of a cytotoxic drug, a cancer cell targeting ligand, and an imaging moiety. The approach is based on the chemical synthesis of polyethylene glycol that at one end is modified by a thioctic acid for controlled attachment to a gold core. The other end of the PEG polymers is modified by a hydrazine, amine, or dibenzocyclooctynol moiety for conjugation with functional entities having a ketone, activated ester, or azide moiety, respectively. The conjugation approach allowed the controlled attachment of doxorubicin through an acid-labile hydrazone linkage, an Alexa Fluor dye through an amide bond, and a glycan-based ligand for the cell surface receptor CD22 of B-cells using strain promoted azide-alkyne cycloaddition. The incorporation of the ligand for CD22 led to rapid entry of the nanoparticle by receptor-mediated endocytosis. Covalent attachment of doxorubicin via hydrazone linkage caused pH-responsive intracellular release of doxorubicin and significantly enhanced the cytotoxicity of nanoparticles. A remarkable 60-fold enhancement in cytotoxicity of CD22 (+) lymphoma cells was observed compared to non- targeted nanoparticles.

High-grade B-cell Lymphoma With MYC Rearrangement and Without BCL2 and BCL6 Rearrangements Is Associated With High P53 Expression and a Poor Prognosis.

Patients with MYC/BCL2 double-hit lymphoma (DHL) are known to have an aggressive clinical course and to respond poorly to various therapies including intensive chemotherapy and stem cell transplant. Less is known about high-grade B-cell lymphoma with MYC rearrangement without concomitant BCL2 and BCL6 rearrangement, designated here as single-hit lymphoma (SHL). In this study, we assessed 61 cases of SHL and compared them with 83 cases of DHL, all confirmed by MYC, BCL2, and BCL6 fluorescence in situ hybridization studies. Although many clinicopathologic features overlap between patients with SHL and those with DHL, distinct features were observed in SHL. Patients with SHL had tumors with a higher prevalence of p53 overexpression (P=0.047), less frequent expression of CD10, BCL2, and BCL6 (P<0.05), and less often had a history of low-grade B-cell lymphoma (P=0.01). In addition, MYC was more frequently partnered with IGH in SHL than in DHL (P=0.04). With a median follow-up of 25 months, the overall survival of 61 SHL patients was poor and similar to that of DHL patients (2-y overall survival rate of 41% in SHL vs. 48% in DHL; P=0.35) and significantly worse than patients with diffuse large B-cell lymphoma and B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma, without MYC and BCL2 rearrangements (P<0.0001). In conclusion, patients with SHL have distinct clinicopathologic features but a similar poor prognosis compared with patients with MYC/BCL2 DHL. The poor prognosis of patients with SHL may be partially related to the higher frequency and level of p53 expression in these tumors.

Discordant lymphoma consisting of mediastinal large B-cell lymphoma and nodular sclerosis Hodgkin lymphoma in the right supraclavicular lymph nodes: a case report.

BACKGROUND: Discordant lymphoma is defined by the simultaneous presence of two or more distinct types of lymphomas at different anatomic sites. With fewer than 20 studies reporting cases of discordant lymphoma to date, the incidence of this condition is believed to be very low. CASE PRESENTATION: Here, we report a case of discordant lymphoma in a 34-year-old female patient that involved mediastinal large B-cell lymphoma and nodular sclerosis Hodgkin lymphoma in the right supraclavicular lymph nodes. The patient presented with a mass in the mediastinum and enlargement of the right supraclavicular lymph nodes, but no obvious signs of lymphoma. Histological examination revealed that the encapsulated mediastinal mass contained medium- or large-size tumor cells with lightly stained cytoplasm and round vesicular nuclei as well as a high percentage of mitotic cells; strongly positive immunohistochemical staining for PAX5, CD20, and CD79a also was observed. Examination of biopsied right supraclavicular lymph node tissues revealed separation by collagen fibers, extensive inflammatory cell infiltration, and large-size tumor cells, such as Reed-Sternberg cells. These tissues stained strongly positive for PAX5 and CD30, weakly positive for CD15, and negative for Epstein-Barr viral RNA. We also found monoclonal gene rearrangement in the immunoglobulin heavy chain gene in the mediastinal large B-cell lymphoma, but no monoclonal gene rearrangement in the nodular sclerosis Hodgkin lymphoma. These findings suggested that these two lymphomas were not of a common clonal origin. The patient was treated by surgical excision of the mediastinal mass followed by radio-chemotherapy, and no metastasis or recurrence occurred during a follow-up period of 32 months. CONCLUSION: A review of previously reported cases indicated that the clinical manifestations and pathological features of discordant lymphoma are diverse due to variation in the types of lymphomas involved. Physicians must have an awareness of discordant lymphoma to avoid incorrect and missed diagnoses, especially considering that the true incidence may not be as low as previously believed.

Inconclusive flow cytometric surface light chain results; can cytoplasmic light chains, Bcl-2 expression and PCR clonality analysis improve accuracy of cytological diagnoses in B-cell lymphomas?

BACKGROUND: Flow cytometric immunophenotyping (FCI), is widely used in cytology for distinguishing between B-cell lymphoma (BCL) and reactive lymphocytic proliferations (RLP), mainly by identifying monotypic B-cell populations. Since this cannot always be determined by ratios of surface immunoglobulin light chains (sIg LCs) we wanted to assess if cytoplasmic immunoglobulin (cIg) LCs, Bcl-2 and polymerase chain reaction (PCR) based clonality analysis can improve accuracy of cytological diagnoses of BCL. METHODS: Our study included 98 fine needle aspiration biopsies from lymph nodes suspicious for BCL with inconclusive sIg LCs. In all cases PCR clonality analysis was performed in order to determine immunoglobulin heavy chain (IGH) gene and T-cell receptor (TRC) gene rearrangement. In selected cases expression of Bcl-2 and cIg LC were determined by FC. RESULTS: Thirty patients had lymphoma and 68 had reactive lymphocytic proliferations. Three patterns of sIg LCs staining were found: negative, dual positive and difficult to interpret. Percentage of lymphomas was highest in the dual positive group (75 %). Morphology coupled with cIg LCs determination and/or Bcl-2 expression was able to give a correct diagnosis in 83 % of cases. Molecular tests would have been misleading in 15 % of cases because 7/30 BCL were polyclonal and 8/68 RLP were monoclonal. CONCLUSIONS: Determination of cIg LCs, Bcl-2 expression and PCR clonality analysis of B cells improved accuracy of cytological diagnoses in BCL with inconclusive sIg LC. However, clonality determined by PCR was misleading in some cases.

Utility of immunohistochemistry with an antibody against MYC at the initial diagnosis of follicular lymphoma, grade 3A, for predicting a more aggressive clinical course: a case report and review of the literature.

Follicular lymphoma (FL) is the most common indolent lymphoma, and associated with the chromosomal translocation t(14;18)(q32;q21). While, FL harboring both BCL2 and MYC translocation at diagnosis is very rare. The evaluation of MYC expression in typical FL at presentation using southern blot, G-banded karyotyping or fluorescence in situ hybridization (FISH) analyses has been described so far. However, there are no reports about the use of immunohistochemistry (IHC) to evaluate MYC protein expression in FL at presentation. Here, we present a FL patient who transformed to a B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt's lymphoma, accompanied by concurrent BCL2, BCL6, and MYC translocations; i.e., triple-hit lymphoma. Paraffin-embedded tissue section-FISH analysis demonstrated that the FL was negative for MYC, but MYC protein expression was subsequently detected in the lymph node specimen obtained at the initial diagnosis using IHC. This case revealed aggressive clinical course and central nervous system involvement. In the literature concerning MYC positive FL five out of 8 patients were dead within 24 months. The detection of MYC protein expression in FL using IHC might be useful to predict more aggressive clinical course.

Drug-Free Macromolecular Therapeutics--A New Paradigm in Polymeric Nanomedicines.

This review highlights a unique research area in polymer-based nanomedicine designs. Drug-free macromolecular therapeutics induce apoptosis of malignant cells by the crosslinking of surface non-internalizing receptors. The receptor crosslinking is mediated by the biorecognition of high-fidelity natural binding motifs (such as antiparallel coiled-coil peptides or complementary oligonucleotides) that are grafted to the side chains of polymers or attached to targeting moieties against cell receptors. This approach features the absence of low-molecular-weight cytotoxic compounds. Here, we summarize the rationales, different designs, and advantages of drug-free macromolecular therapeutics. Recent developments of novel therapeutic systems for B-cell lymphomas are discussed, as well as relevant approaches for other diseases. We conclude by pointing out various potential future directions in this exciting new field.

PET/CT Assessment of Follicular Lymphoma and High Grade B Cell Lymphoma - Good Correlation with Clinical and Histological Features at Diagnosis.

BACKGROUND: Follicular lymphoma is a common type of non-Hodgkin's lymphoma observed in Western countries. The diagnosis of this disease is based primarily on morphological and immunohistochemical assessment. The proliferative index Ki67 correlates with histological grading and clinical aggressiveness. Currently, positron emission tomography/computed tomography scanning are not applied for standard staging at diagnosis of follicular lymphoma and its use is limited to those patients for whom the identification of residual disease is crucial for therapeutic decisions and only when transformation to a high-grade lymphoma is suspected. OBJECTIVES: Our aim was to assess whether a correlation exists between the maximal standardized uptake value (SUVmax) at the biopsy site as detected via positron emission tomography/computed tomography and pathological (Ki67 and FL histological grade) and clinico-biological features (e.g. LDH, beta-2-microglobulin, Ann Arbor stage and FL International Prognostic Index--FLIPI) at diagnosis. MATERIAL AND METHODS: We retrospectively identified 16 patients during the previous 3.5 years in whom node biopsies were guided, taking into account the SUVmax as detected upon PET/CT scan at diagnosis. The results of these biopsies were diagnostic of follicular lymphoma. We also included 6 patients with high grade B cell lymphoma: 5 diffuse large B cell lymphoma (DLBCL) and 1 FL 3b histological grade. A 2-tailed non-parametric Spearman's correlation analysis of the SUVmax with Ki67, histological grade, LDH and b-2-microglobuline was performed. RESULTS: The Ki67 (r=0.73) and follicular lymphoma histological grade (r=0.75) at the biopsy displayed a significant correlation with the SUVmax at diagnosis (p<0.01). CONCLUSIONS: Our results suggest that SUV detected by positron emission tomography/computed tomography correlates with histological grade in follicular lymphoma/high grade B cell lymphoma, Ki67 and LDH. Positron emission tomography/computed tomography should be considered for guiding lymph node biopsy when transformation to a high-grade B cell lymphoma is suspected.

Use of a conformational switching aptamer for rapid and specific ex vivo identification of central nervous system lymphoma in a xenograft model.

Improved tools for providing specific intraoperative diagnoses could improve patient care. In neurosurgery, intraoperatively differentiating non-operative lesions such as CNS B-cell lymphoma from operative lesions can be challenging, often necessitating immunohistochemical (IHC) procedures which require up to 24-48 hours. Here, we evaluate the feasibility of generating rapid ex vivo specific labeling using a novel lymphoma-specific fluorescent switchable aptamer. Our B-cell lymphoma-specific switchable aptamer produced only low-level fluorescence in its unbound conformation and generated an 8-fold increase in fluorescence once bound to its target on CD20-positive lymphoma cells. The aptamer demonstrated strong binding to B-cell lymphoma cells within 15 minutes of incubation as observed by flow cytometry. We applied the switchable aptamer to ex vivo xenograft tissue harboring B-cell lymphoma and astrocytoma, and within one hour specific visual identification of lymphoma was routinely possible. In this proof-of-concept study in human cell culture and orthotopic xenografts, we conclude that a fluorescent switchable aptamer can provide rapid and specific labeling of B-cell lymphoma, and that developing aptamer-based labeling approaches could simplify tissue staining and drastically reduce time to histopathological diagnoses compared with IHC-based methods. We propose that switchable aptamers could enhance expeditious, accurate intraoperative decision-making.

Triple-hit B-cell Lymphoma With MYC, BCL2, and BCL6 Translocations/Rearrangements: Clinicopathologic Features of 11 Cases.

Lymphomas with translocations/rearrangements of MYC, BCL2, and BCL6, so-called triple-hit B-cell lymphoma, are rare, and few studies on these tumors are available in the literature. We report 11 cases of triple-hit B-cell lymphoma and characterize their clinicopathologic findings. All patients were men, with a median age of 64 years (range, 45 to 80 y), and 4 patients had antecedent or concurrent follicular lymphoma. Using the 2008 World Health Organization classification, these cases were classified as: 5 B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma; 4 DLBCL; 1 DLBCL with concurrent follicular lymphoma; and 1 low-grade follicular lymphoma. All cases were positive for CD10, BCL2, and FOXP1. Ten of 11 cases were positive for CD20. MYC expression was high in 10/11 (91%), BCL6 was positive in 8/11 (73%), and MUM1/IRF4 was positive in 6/11 (55%) cases. T-cell antigens, TdT, and Epstein-Barr virus-encoded RNA were negative in all cases. Ten of 11 cases showed a high proliferation index-70% to 100%, and the follicular lymphoma had a 30% proliferation rate. Using most algorithms, all cases belonged to germinal center B-cell-like group. All patients received standard or more aggressive immunochemotherapy regimens. Three patients had no response to chemotherapy; 4 patients showed a partial response; 2 patients had complete remission after chemotherapy; and 2 patients had just begun chemotherapy. Three patients underwent a stem cell transplant. The median follow-up time was 5.3 months. Five patients died, and 6 patients were alive at last follow-up. Two patients who underwent stem cell transplant after complete response to chemotherapy were in remission with 16 to 19 months of clinical follow-up. In summary, triple-hit lymphomas are clinically aggressive tumors associated with a poor prognosis. Patients often respond poorly to chemotherapy, but a subset may completely respond to chemotherapy followed by stem cell transplant.