T-cell-rich B-cell lymphomas: diagnosis and response to therapy of 44 patients

Clinical features and survival of patients with T-cell/histiocyte-rich large B-cell lymphoma: analysis of the National Cancer Data Base

Using data from the National Cancer Data Base, 2010-2015, we examined characteristics and outcomes of T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL, N = 622) relative to unspecified diffuse large B-cell lymphoma (DLBCL-NOS, N = 91,588) and nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL, N = 2240). Socio-demographic characteristics of patients with THRLBCL resembled more NLPHL than DLBCL-NOS. Five-year overall survival in THRLBCL was 66% (95% confidence interval [CI], 60-71%). Adjusting for clinical and socio-economic covariates, THRLBCL was associated with better survival than DLBCL-NOS (adjusted hazard ratio, 0.80; 95%CI, 0.67-0.94). This association was similar in academic and community hospitals and consistent in a model stratified by the revised International Prognostic Index. Prognostic factors in THRLBCL included age, comorbidity index, and extranodal primary site, but not stage. Adjusted odds of prior NLPHL were 18.2 higher for THRLBCL (95%CI, 7.2-45.7) than DLBCL-NOS. These large-scale epidemiologic data support the relationship between THRLBCL and NLPHL, and suggest improved prognosis with modern rituximab-based immunochemotherapy.

T-cell/histiocyte-rich large B-cell lymphoma in a child: A case report and review of literature

T-cell/histiocyte-rich large B-cell lymphoma is uncommon in children population. There were few cases reported in the literature with wide range clinical presentations including advanced stage, and more involvement of liver, spleen and bone marrow. Head and neck lymphadenopathy tends to present in younger children. We report a case of 10-year-old boy who initially presented intermittent fever, headaches and neck lymphadenopathy. Subsequently, he developed diffuse lymphadenopathy and hepatosplenomegaly. T-cell/histiocyte-rich large B-cell lymphoma was diagnosed on a cervical lymph node biopsy. Cervical lymphadenopathy in this age group is most commonly reactive or non-malignant processes. Lymphoma is much less frequent; mainly are non-Hodgkin lymphomas. However, a subset of large B-cell lymphoma called T-cell/histiocyte- rich B-cell lymphoma is rare in children.

A Case of Chemotherapy-Refractory "THRLBCL like Transformation of NLPHL" Successfully Treated with Lenalidomide

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is a subtype of nonclassical Hodgkin lymphoma (HL). It resembles non-Hodgkin lymphoma (NHL), by expressing classic B cell markers such as CD20 and CD79a however lacks definitive HL markers (such as CD15 and CD30). T cell histiocyte-rich large B cell lymphoma (THRLBCL), on the other hand, is a distinct entity classified under NHL and considered a variant of diffuse large B cell lymphoma (DLBCL). NLPHL can look morphologically and immunologically similar to THRLBCL and often poses a diagnostic challenge. Neoplastic cells in both NLPHL and THRLBCL express B cell markers and are typically scattered in a background of reactive cells. The two major differences are the background cell type and the morphologic pattern. Despite having a phenotypic resemblance, they have distinct biologic behavior and clinical course. NLPHL typically has an indolent course, and THRLBCL has an aggressive course. Hence, differentiating these two entities is critical not only for prognosis but for treatment purposes. Of note, NLPHL has a small risk of transformation to an aggressive lymphoma such as THRLBCL.

Pancreatic T/histiocyte-rich large B-cell lymphoma: A case report and review of literature

Primary pancreatic lymphoma (PPL) is an extremely rare form of extranodal malignant lymphoma. The most common histological subtype of PPL is diffuse large B cell lymphoma (DLBCL). In rare cases, PPL can also present as follicular lymphoma, small lymphocytic lymphoma, and T cell lymphoma either of non-Hodgkin’s lymphoma or of Hodgkin’s lymphoma. T-cell/histiocyte-rich large B-cell lymphoma (T/HRBCL) is an uncommon morphologic variant of DLBCL with aggressive clinical course, it is predominantly a nodal disease, but extranodal sites such as bone marrow, liver, and spleen can be involved. Pancreatic involvement of T/HRBCL was not presented before. Herein, we report a 48-year-old male who was hospitalized with complaints of jaundice, dark brown urine, pale stools, and nausea. The radiological evaluation revealed a pancreatic head mass and, following operative biopsy, the tumor was diagnosed as T/HRBCL. The patient achieved remission after six cycles of CHOP chemotherapy. Therefore, T/HRBCL can be treated similarly to the stage-matched DLBCL and both of them get equivalent outcomes after chemotherapy.

T Cell/Histiocyte-Rich Large B Cell Lymphoma of the Thymus: A Diagnostic Pitfall

T cell/histiocyte-rich large B cell lymphoma (THRLBCL) is predominantly a nodal disease, with extranodal involvement, such as bone marrow, spleen, and liver. However, primary THRLBCL has never been reported in the thymus in the English literature. Here we report a case of THRLBCL presenting as mediastinal mass and lymphadenopathy. Based on the frozen section diagnosis of "thymoma," a 12 cm mass was excised. A year later she developed multiple enlarged lymph nodes and pulmonary nodules. Consultant review of the excised mediastinal mass showed scattered large atypical cells that were CD20+ and PAX-5+ and negative for pan-cytokeratin, AE1, and AE3, compatible with THRLBCL and excluding thymoma. The excised lymph nodes were replaced by diffuse infiltrate of small CD3+ lymphocytes and histiocytes with intermingled large CD20+ B lymphoma cells scattered throughout the section. A diagnosis of THRLBCL was made in lymph node, similar to previous thymic lesion. A clonal rearrangement of immunoglobulin heavy chain (IGH) gene was detected, further supporting the diagnosis. This is the first reported case of THRLBCL in thymus. Correct recognition of this entity is critical, because of the difference in therapeutic impact on these patients.

Risk assessment in the management of newly diagnosed classical Hodgkin lymphoma

Treatment of Hodgkin lymphoma is associated with 2 major types of risk: that the treatment may fail to cure the disease or that the treatment will prove unacceptably toxic. Careful assessment of the amount of the lymphoma (tumor burden), its behavior (extent of invasion or specific organ compromise), and host related factors (age; coincident systemic infection; and organ dysfunction, especially hematopoietic, cardiac, or pulmonary) is essential to optimize outcome. Elaborately assembled prognostic scoring systems, such as the International Prognostic Factors Project score, have lost their accuracy and value as increasingly effective chemotherapy and supportive care have been developed. Identification of specific biomarkers derived from sophisticated exploration of Hodgkin lymphoma biology is bringing promise of further improvement in targeted therapy in which effectiveness is increased at the same time off-target toxicity is diminished. Parallel developments in functional imaging are providing additional potential to evaluate the efficacy of treatment while it is being delivered, allowing dynamic assessment of risk during chemotherapy and adaptation of the therapy in real time. Risk assessment in Hodgkin lymphoma is continuously evolving, promising ever greater precision and clinical relevance. This article explores the past usefulness and the emerging potential of risk assessment for this imminently curable malignancy.

T cell/histiocyte-rich large B-cell lymphoma: an update on its biology and classification

T cell/histiocyte-rich large B-cell lymphoma (THRLBCL), originally considered an uncommon variant of Diffuse Large B-Cell Lymphoma (DLBCL), is recognized by the World Health Organisation as a separate clinicopathological entity since 2008. It predominantly affects middle aged men often presenting with advanced stage disease frequently involving spleen, liver and bone marrow at time of diagnosis. According to the WHO, this lymphoma is morphologically characterized by less than 10% of large neoplastic B cells in a background of abundant T cells and frequently histiocytes. Differentiating THRLBCL from other lymphoproliferative disorders such as Nodular Lymphocyte Predominant Hodgkin Lymphoma (NLPHL) and Lymphocyte-Rich classical Hodgkin lymphoma (LRcHL) is important from a clinical point of view and can be achieved in most cases, given adequate biopsy specimens, by careful morphological and immunohistochemical evaluation of both the neoplastic cells as well as the nonneoplastic stromal component. According to this WHO definition, THRLBCL is still considered a clinically heterogeneous entity, though it is noted that especially the cases containing numerous histiocytes behave aggressively and show resistance to current therapies for DLBCL. Gene expression profiling studies of THRLBCL provided evidence for a prominent role for this histiocytic component that is important for a tolerogenic host immune response in which they may assist neoplastic cells in escaping the T cell-mediated immune surveillance. Therefore, reserving the diagnosis of THRLBCL to cases containing a large proportion of histiocytes might be relevant, as modulating their activity could provide new therapeutic options.

Therapy Outcome of a T-Cell-Rich-B-Cell Lymphoma (TCRBCL) Patient with R-CHOP in Ibadan, Nigeria: a Case Report

T-cell-rich B-cell lymphoma (TCRBCL) is considered a rare variant of aggressive B cell lymphoma characterized by few neoplastic B cells and a large reactive infiltrate with striking similarities to nodular lymphocyte predominant Hodgkin’s lymphoma.

A case of a 46 year old man referred with a 5 months history of generalized lymphadenopathy, weight loss, low grade pyrexia and two separately reported lymph node histology consistent with TCRBCL is described.

The clinical course was indeed aggressive because in spite of initial treatment with four cycles of CHOP combination chemotherapy, followed by R+CHOP(x 6 cycles), signs of tumor re-growth/infiltration were frequently observed. Also, recurrent infection was frequent, troublesome and eventually became overwhelming resulting to the loss of the patient.

This case, being the first case of TCRBCL diagnosed by immunohistochemical confirmation and managed at this centre with R-CHOP, is presented to highlight the dilemma in making diagnosis, clinical challenges faced and rituximab therapy outcome especially in resource poor country. It will also serve to increase our index of suspicion and the need reinforce immunohistochemistry in the diagnosis of lymphoma.

Histiocytic and t-cell rich b-cell lymphoma (TCRBCL) of the stomach

Although stomach is a frequent site of extranodal lymphomas, histiocyte-rich TCRBCL has not yet been described there. Even histology of repeated gastrobiopsies of this uncommon, diffuse, large B-cell lymphoma may be inconclusive and partial gastrectomy cannot be avoided. It is only immunohistology (CD20, CD43, CD68) of the paraffin blocks from the resection specimen that can lead to the final diagnosis of intermediate grade malignant lymphoma.

T-cell/histiocyte-rich B-cell lymphoma: Clinical presentation, management and prognostic factors: report on 61 patients and review of literature

T-cell/histiocyte-rich B-cell lymphoma (TC/HRBCL) is a rare subtype of diffuse large B-cell non-Hodgkin's lymphoma (DLBCL) with characteristic morphologic and immunophenotypic features, often misdiagnosed as Hodgkin's lymphoma and peripheral T-cell lymphoma. Few and conflicting clinical data are available in the literature addressing optimal treatment, prognosis and outcome. We retrospectively reviewed all patients diagnosed and managed at our institution between 1995 and 2004 diagnosed with T-cell-rich-B-cell lymphoma by WHO criteria. Sixty-one patients were identified. Initial pathology was incorrect in 82% of referred cases. The median age was 30 years. Seventy-one patients were males. Stage distribution was I - II in 21 patients, and III - IV in 40. Fifty-two percent of patients (32) had splenic involvement and thirty-seven patients (61%) presented with extranodal disease (22 >or= 2 sites). The International Prognostic Index (IPI) score was >or=2 in 62% of patients. All 59 newly diagnosed TC/HRBCL patients were treated with CHOP or R-CHOP combination chemotherapy +/- radiation therapy. The overall response rate was 85% and nine patients progressed on therapy. Fourteen patients relapsed with a median time of relapse of 6 months (range, 2 - 28). At a median follow-up of 22 months (range 1 - 132); 32 patients (52%) are alive with no evidence of disease. The 5-year overall survival and event free survival rates were 46% and 39% respectively. To conclude, TC/HRBCL is difficult to recognize without immunohistochemistry. It has an aggressive course and poor outcome; with most of patients presenting with advanced disease stage together with high IPI score. Treatment outcome seems to be similar to IPI matched DLBCL counterpart.

T-cell/histiocyte-rich B-cell lymphoma: biology, diagnosis, and management

T-cell/histiocyte-rich B-cell lymphoma (T/HRBCL) is an uncommon morphologic variant of diffuse large B-cell lymphoma (DLBCL). Pathologically, it is distinguished by <10% malignant B cells amid a majority population of reactive T lymphocytes and histiocytes. Diagnosis of this entity is occasionally difficult, as it may appear similar to other lymphoid diseases, such as nodular lymphocyte-predominant Hodgkin's lymphoma and classic Hodgkin's lymphoma. Accurate diagnosis therefore rests with careful immunohistochemical analysis of the tumor cells and the inflammatory microenvironment. Clinically, T/HRBCL occurs in younger patients, predominantly affects men, and involves the liver, spleen, and bone marrow with greater frequency than traditional DLBCL. Despite the unique clinical features and robust host inflammatory response, T/HRBCL follows a natural history similar to those of other DLBCLs and responds similarly to therapy. Recent gene expression analysis demonstrates that a productive relationship with the host immune response may extend beyond this small DLBCL variant to include as many as one third of all DLBCLs. At present, T/HRBCL should be treated similarly to other stage-matched DLBCLs, though future therapies will likely be targeted at the relationship of the tumor cells with their inflammatory microenvironment.

Pediatric EBV-positive T-cell/histiocyte-rich large B-cell lymphoma with clonal cells in the bone marrow without overt involvement

T-cell/histiocyte-rich large B-cell lymphoma (TCHRLBCL) is a variant of large B-cell lymphoma only rarely encountered in children. Here we report the case of an 8-year-old African American boy with Epstein-Barr virus (EBV)-positive TCHRLBCL who initially presented with right submandibular, anterior cervical and supraclavicular lymphadenopathy. Cytogenetic analysis of the lymph node revealed a near-triploid karyotype with complex chromosomal aberrations. Although morphologically the bone marrow was normal, the same cytogenetically abnormal clone was detected. The patient responded to chemotherapy with CHOP (doxorubicin, cyclophosphamide, vincristine and prednisone) therapy, with disappearance of the abnormal clone from the bone marrow. The patient remains in remission 26 months after the initial diagnosis.

T-cell-rich B-cell lymphoma: a clinicopathologic study of 21 cases and comparison with 43 cases of diffuse large B-cell lymphoma

Clinicopathologic features of 21 patients with T-cell-rich B-cell lymphoma (TCRBCL) were reviewed and compared to 43 patients with diffuse large B-cell lymphoma (DLBCL) to determine if there were distinguishing clinical characteristics and differences in response or survival to CHOP therapy. For the diagnosis of TCRBCL, the current WHO criteria was used. In all of our cases, the majority of cells are non-neoplastic T cells and <10% large neoplastic B cells are present. The initial pathologic diagnosis was nodular lymphocyte predominant Hodgkin's lymphoma (NLPHL) in two cases. Patients with TCRBCL were significantly younger (median: 46 years) and had a significantly higher incidence of B symptoms (62%), hepatomegaly (33%) and marrow infiltration (33%) at presentation when compared to DLBCL (P<0.03). The CR rate after treatment was 48% for TCRBCL patients versus 79% for the DLBCL (P<0.003). Although the CR rates in between the two groups are significant, the difference in 3 years survival rates in each CR groups was insignificant (80% versus 77%). The overall survival time in the two groups was 17 months. Event-free survival time in TCRBCL was 12 months, compared with 17 months in the DLBCL (P>0.05). The frequency of patients with TCRBCL achieving CR was 52.6% whereas that of patients with DLBCL was 79% (P<0.003). The TCRBCL 3 years event-free survival 48% and overall survival 64% were 63 and 72% for DLBCL, respectively.

Rituximab in combination with vinorelbine/gemcitabine chemotherapy in patients with primary refractory or early relapsed T cell rich B cell lymphoma. A pilot study

Rituximab is a chimeric monoclonal antibody that binds specifically to the CD20 antigen expressed in most B cell lymphomas. As single agent or in combination with chemotherapy rituximab has shown significant activity in patients with relapsing or refractory aggressive lymphomas. Because T cell rich B cell lymphomas (TCRBCL) also express the CD20 antigen, we decided to evaluate the efficacy and tolerability of the anti-CD20 monoclonal antibody rituximab combined with chemotherapy in four patients with either primary refractory or early relapsed TCRBCL. The chemotherapy regiment consisted of vinorelbin and gemcitabine, a combination with known efficacy in patients with refractory aggressive lymphomas. The patients received 6 cycles of rituximab at the dose of 375 mg/m(2), combined with vinorelbine 25 mg/m(2) and gemcitabine 800 mg/m(2) at 3-week intervals. Three complete responses and one partial response were observed among our four patients with refractory or early relapsed TCRBCL without significant adverse effects, indicating considerable efficacy of this combination. Therefore, rituximab should be tested in combination with chemotherapy in the front line treatment of patients with TCRBCL.

Favorable response to treatment of a child with T-cell-rich large B-cell lymphoma presenting with liver failure

The authors describe the successful management of a child with T-cell-rich large B-cell lymphoma (TCRBCL) involving the lymph nodes and liver, causing severe hepatic dysfunction. After immunohistochemical confirmation of the diagnosis, the patient was treated initially with low-dose, non-hepatotoxic chemotherapy and irradiation to the porta hepatis. Chemotherapy was gradually escalated to intensified B cell-lymphoma treatment regimens (CHOP, CYVE, COPAdM) as liver function improved. Despite prompt and notable response in the lymph nodes, the intrahepatic nodular lesions persisted radiologically. Liver function tests normalized during the course of treatment. However, radiologic studies of the liver showed abnormal regeneration with a predominant left lobe overshadowing a tiny right lobe. The patient remains in remission more than a year after completion of treatment. Judicious use of chemotherapeutic agents with or without local radiotherapy may influence the outcome and survival in children with TCRBCL involving the liver and causing abnormal hepatic function.

T-cell/histiocyte-rich large B-cell lymphomas and classical diffuse large B-cell lymphomas have similar outcome after chemotherapy: a matched-control analysis

PURPOSE

Because it is unclear whether T-cell/histiocyte-rich large B-cell lymphomas (H/TCRBCL) should be considered as a true clinicopathologic entity, we conducted a matched-control analysis comparing patients with H/TCRBCL and patients with diffuse large-B cell lymphoma (B-DLCL).

PATIENTS AND METHODS

More than 4,500 patients were enrolled onto non-Hodgkin's lymphoma trials conducted by the Groupe d'Etude des Lymphomes de l'Adulte. After histologic review, 50 patients were subclassified as H/TCRBCL. They were matched to 150 patients with B-DLCL for each of the factors of the International Prognostic Index (IPI).

RESULTS

Clinical characteristics of H/TCRBCL patients showed a male predominance and a median age of 47 years. Performance status was normal in 89% of patients, whereas lactate dehydrogenase level was increased in 60% of patients. The disease was disseminated in 81% of patients, and 48% had two or more involved extranodal sites. The IPI score was >or= 2 in 53% of patients. The complete response rate to chemotherapy was 63%, and 5-year overall survival (OS) and event-free survival (EFS) rates (mean +/- SD) were 58% +/- 18% and 53% +/- 16%, respectively. The matched-control analysis showed a trend toward a better response to chemotherapy for patients with B-DLCL (P =.06), whereas no difference was observed in OS (P =.9) and EFS (P =.8).

CONCLUSION

H/TCRBCL is an aggressive disease that often presents with adverse prognostic factors. However, when treatment is adapted to the disease risk, outcome is equivalent to that observed in patients with B-DLCL. Thus H/TCRBCL should be considered a pathologic variant that belongs to the B-DLCL category.

T-cell/histiocyte-rich large B-cell lymphoma: a heterogeneous entity with derivation from germinal center B cells

T-cell/histiocyte-rich large B-cell non-Hodgkin's lymphoma (THRLBCL) is an unusual morphologic variant of diffuse large B-cell lymphoma. We reviewed 30 cases of THRLBCL to evaluate its heterogeneity based on morphologic, immunophenotypic, and genetic features. Cases were classified according to the appearance of the large neoplastic B cells into three morphologic variants: 1) lymphocytic and histiocytic (L&H-like) (resembling the L&H cells of nodular lymphocyte predominance Hodgkin's lymphoma (14 cases); 2) centroblast (or immunoblast)-like (10 cases), and 3) Reed-Sternberg cell-like (resembling the neoplastic cells of classic Hodgkin's lymphoma) (6 cases). We used a panel of immunohistochemical stains, including those with specificity for germinal center B cells: CD20, CD79a, CD30, CD15, epithelial membrane antigen, BCL-2, BCL-6, and CD10. The /JH polymerase chain reaction assay was further performed to investigate a relationship to follicular lymphoma. The results were correlated with Epstein-Barr virus status as determined by staining for latent membrane protein and EBER-1 in situ hybridization. All cases were of B-cell immunophenotype with strong surface CD20 reactivity in the neoplastic large lymphoid cells, although CD79a was more inconsistently and weakly expressed (10 of 17). Nuclear positivity for the BCL-6 protein was detected in the tumor cells in 26 of 29 (90%) cases. However, differences in expression of other antigens were encountered in the histologic subtypes. Epithelial membrane antigen positivity, a feature often seen in nodular lymphocyte predominance Hodgkin's lymphoma, was observed in 11 of 30 (37%) cases and was most commonly seen in cases with L&H cell morphology (8 of 14; 57%). CD30 expression was observed in 9 of 30 (30%) cases but was most frequent in cases with Reed-Sternberg-like morphology (3 of 6 [50%]). CD10 expression was infrequent overall (3 of 29; 10%), with 2 of 3 positive cases identified in the centroblastic group. The overall rarity of positivity for CD10, BCL-2 (3 of 22; 13%), and -2 JH rearrangement (1 of 28; 4%) indicates a lack of connection to follicular lymphoma for all subtypes. The three cases that were negative for BCL-6 protein were LMP-1 positive and EBER-1 positive by in situ hybridization, and 2 of 3 had neoplastic cells with Reed-Sternberg-like morphology. These results demonstrate that although a large proportion of THRLBCL represent tumors of germinal center B cell derivation, they exhibit a diversity of morphologic and immunophenotypic features. A subset of THRLBCL may be related to nodular lymphocyte predominance Hodgkin's lymphoma. A small percentage show features closely resembling classic Hodgkin's lymphoma and could be considered a variant of grey zone lymphoma.

Lymphocyte predominant Hodgkin's disease

Lymphocyte predominant Hodgkin's disease (LPHD) is a rare type of B-cell lymphoma with unique pathologic and clinical features that distinguish it from other types of Hodgkin's disease. Patients with LPHD tend to be younger males who present with indolent and asymptomatic lymphadenopathy limited to peripheral lymph nodes. The immunophenotype of the malignant lymphocytic and/or histiocytic cells (CD20+, CD15-, CD30-) forms the basis of the pathologic distinction from the subtypes of classical Hodgkin's disease. Despite an excellent response to aggressive upfront combined-modality treatment, patients with LPHD tend to relapse continuously over decades. The benign nature of these relapses and the incidence of late treatment-related toxicity have raised questions about the need for an aggressive upfront approach. Recent insights into the molecular pathogenesis of LPHD and the development of novel targeted therapies promise to improve future treatment.

T-cell rich B-cell lymphoma: clinical distinctiveness and response to treatment in 45 patients

T-cell rich B-cell lymphoma (TCR-BCL) is a recently described pathologic diagnosis without a place among traditional lymphoma classification systems. In the past, TCR-BCL has been included among other diagnoses, in particular lymphocyte predominant Hodgkin's disease (LPHD). The study of TCR-BCL cohorts may elucidate clinical distinctiveness, response to therapy, and the effect of treatment regimen on outcome. Between 1992 and 1997, a hematopathologist at Memorial Sloan-Kettering Cancer Center (MSKCC) diagnosed 45 patients with TCR-BCL according to published criteria. Clinical data was collected through retrospective chart review and communication with other patient providers. Our patients presented most commonly as males in their fourth decade with advanced stage disease. Three-year overall survival (OS) and failure-free survival (FFS) were 73 and 37%, respectively. Conventional combination chemotherapy regimens were utilized for an aggressive non-Hodgkin's lymphoma (NHL) diagnosis in 26 and for a Hodgkin's disease (HD) diagnosis in 10. Disease-free survival (DFS) was significantly better for NHL (36%) vs. HD (10%) directed chemotherapy at 3 years (p = 0.003). Overall survival at 3 years was not statistically different (62 vs. 79%) due to successful salvage therapy in both groups. It is important to distinguish TCR-BCL from LPHD and classical HD. Advanced stage, extranodal disease, involvement of the mediastinum, mesentery and/or spleen are clinical clues to a TCR-BCL diagnosis. Chemotherapy directed to a NHL diagnosis rather than HD results in a significant improvement in disease-free survival. Initial Hodgkin's disease-directed (HD-directed) chemotherapy should be avoided, although salvage transplantation may result in prolonged survival.

T-cell-rich B-cell lymphoma - diagnostic and therapeutic aspects

BACKGROUND

Morphologically, T-cell-rich B-cell lymphoma (TCRB-NHL) may be indistinguishable from Hodgkin's disease (HD). Immunophenotyping may be helpful in the separation of these entities. TCRB-NHL is occasionally misdiagnosed and treated as HD. However, information is limited regarding clinical characteristics and outcome of this patient population. Furthermore, knowledge concerning any association with Epstein-Barr virus (EBV) in TCRB-NHL, as well as the immunophenotype of reactive T-cells and the expression of T-cell intracellular antigen-1 (TIA-1), granzyme B (GrB) and the CD3-zeta-chain is limited.

PATIENTS AND METHODS

We have re-evaluated 251 tumour biopsies from patients aged > or =15 years with HD diagnosed 1985-1994. Reclassification from HD to TCRB-NHL was done in 12 cases (5%). Six TCRB-NHL patients initially diagnosed and treated as B-NHL were also included. All TCRB-NHL biopsies were analysed for latent membrane protein 1 (LMP-1), CD4, CD8, CD56, CD57, TIA-1, GrB and CD3-zeta-chain.

RESULTS

Twelve cases of TCRB-NHL were initially subclassified as HD (lymphocyte predominance 5, nodular sclerosis 3, and mixed cellularity 4). Of these 12 TCRB-NHL patients, 6 were given radiotherapy alone, 5 MOPP/ABVD or similar combination chemotherapy, and one patient combined modality treatment. Male sex (p<0.05) and inguinal involvement (p<0.001) were significantly more frequent when TCRB-NHL patients receiving HD treatment (n=12) were compared with the remaining patients with confirmed (conf) HD, while no significant differences were seen with regard to stage, bone marrow infiltration, splenomegaly or cause-specific survival. Similar results were achieved when all TCRB-NHL patients (n=18) were compared to conf HD patients. Lymphoma cells in three samples stained positively for LMP-1. A decreased expression of CD3-zeta-chain was seen in 9/14 tumour biopsies.

CONCLUSION

Immunohistochemistry makes it possible to identify cases of TCRB-NHL that are morphologically difficult to distinguish from HD. The outcome of TCRB-NHL patients treated as having HD was comparable with that of the remaining HD population.

T-cell/histiocyte-rich large B-cell lymphoma: a distinct clinicopathologic entity

PURPOSE

Although it has proven difficult to delineate diagnostically reproducible and clinically relevant subgroups, the heterogeneity of diffuse large B-cell lymphomas (DLBCL) is widely acknowledged. In 1992, we reported on six cases that suggested that large B-cell lymphoma rich in stromal histiocytes and T cells may be identified as a distinct clinicopathologic entity within DLBCL.

PATIENTS AND METHODS

An integrated clinicopathologic study of 40 cases of this DLBCL subtype is presented.

RESULTS

Distinguishing a DLBCL rich in histiocytes and reactive T cells, designated T-cell/histiocyte--rich large B-cell lymphoma (THR-BCL), may be justified from a clinical point of view. The disease typically affects middle-aged male patients who usually present with advanced-stage disease that is not adequately managed with current therapeutic strategies. Whereas proliferation fraction and p53 overexpression, in addition to the clinical variables incorporated in the International Prognostic Index (IPI), significantly correlate with response to treatment and survival in a univariate analysis, only the IPI score identifies relevant prognostic THR-BCL subpopulations in a multivariate model. The morphologic and immunophenotypic profile of the neoplastic B cells in THR-BCL suggests that they may originate from a germinal center ancestor.

CONCLUSION

THR-BCL constitutes a distinct clinicopathologic entity that is characterized by an aggressive behavior. Experimental therapeutic strategies may be indicated to obtain a more favorable response to treatment in this disease.

Histiocyte-rich, T-cell-rich B-cell lymphoma: a distinct diffuse large B-cell lymphoma subtype showing characteristic morphologic and immunophenotypic features

AIMS

The clinicopathological features of histiocyte-rich, T-cell-rich B-cell lymphoma (HRTR-BCL) were first recognized in 1992. In this study, 60 cases of HRTR-BCL were analysed in order to provide a detailed morphological and immunophenotypical profile of the disorder.

METHODS AND RESULTS

HRTR-BCL is easily distinguished from other B-cell lymphomas rich in stromal T-cells by (i) a diffuse or vaguely nodular growth pattern, (ii) the presence of a minority population of CD15-, CD20+ large neoplastic B-cells, (iii) a prominent stromal component composed of both T-cells and non-epithelioid histiocytes, and (iv) the scarcity of small reactive B-cells. These criteria also enable a reliable distinction from lymphocyte-rich classical Hodgkin's lymphoma (CHL), from lymphocyte-predominant Hodgkin's lymphoma (LPHL), paragranuloma type and from peripheral T-cell lymphoma. Based on the morphology of the neoplastic cells and on their frequent bcl-6 immunoreactivity, we speculate that HRTR-BCL may be derived from a progenitor cell of germinal centre origin.

CONCLUSIONS

HRTR-BCL presents characteristic clinical features, affecting predominantly middle-aged men who present with advanced stage disease and are at high risk of treatment failure. Considering these distinctive clinicopathological features, recognizing HRTR-BCL as a lymphoma entity may be justified.

Durable remission in recurrent T-cell-rich B-cell lymphoma with the anti-CD20 antibody rituximab

A diagnostic continuum exists between lymphocyte-predominant Hodgkin's disease, T-cell-rich B-cell lymphoma (TCRBCL), and diffuse large B-cell lymphoma. While TCRBCLs are uncommon, their clinical and morphologic presentation can mimic other Hodgkin's and non-Hodgkin's lymphomas from which they must be distinguished for diagnosis and treatment. We present an unusual case of a 30-year-old man with recurrent TCRBCL arising from lymphocyte-predominant Hodgkin's disease with remarkable response to treatment with the anti-CD20 antibody, rituximab.

Prognostic significance of tumour-infiltrating T lymphocytes and T-cell subsets in de novo diffuse large B-cell lymphoma: a multiparameter flow cytometry study

Tumour-infiltrating T lymphocytes (TIL-T) have been implicated in playing a role in controlling tumour growth. We evaluated TIL-T in 55 cases of de novo diffuse large B-cell lymphoma (DLBCL) using three- or four-colour flow cytometric immunophenotyping (FCI). The percentage of TIL-T varied from 3% to 72% of total viable cellular events (mean 32 +/- 20%). The CD4:CD8 ratio varied from 0.17 to 13 (mean 2.3 +/- 2.2). Cases with >/= 20% T cells and those with CD4:CD8 ratios > or = 2.0 showed a significantly better overall survival (P = 0.017 and P = 0.034 respectively). These findings were independent of clinical stage at diagnosis. The T-cell percentage and CD4:CD8 ratio were moderately correlated (Spearman correlation coefficient = 0.47, P = 0.001) and multivariate analysis revealed that the association of the two factors with prognosis was mutually dependent. The T cells in 23 cases were studied for CD45RO. The mean percentage of total T cells expressing CD45RO was 86 +/- 10%. There was a trend towards better survival for those patients with a higher percentage of CD45RO+ T cells (P = 0.06). These results suggest that TIL-T, particularly CD4+ T cells, may play a role in the control of DLBCL, and measurement of T-cell percentage and T-cell subsets using FCI may be useful in predicting the clinical behaviour of DLBCL.

T Cell and NK Cell Lymphoproliferative Disorders

This review covers the diagnosis and management of natural killer and peripheral T-cell lymphomas (PTCL). Problems with PTCL include their rarity, representing usually 10-15% of non-Hodgkin's lymphomas in the Western Hemisphere, morphologic heterogeneity, and lack of immunophenotypic markers for clonality. Additionally, their clinical behavior is variable and may not correlate with morphology.

Dr. Kinney gives a general overview of the diagnosis of PTCL and NK cell neoplasms. Emphasis will be placed on extranodal T cell and natural killer (NK) cell lymphomas such as hepatosplenic lymphoma, subcutaneous panniculitis-like lymphoma and nasal/nasal type T/NK-cell lymphoma. The use of ALK gene regulation in the classification of anaplastic large cell lymphoma is also reviewed.

Dr. Loughran describes current understanding of the pathogenesis of large granular lymphocyte (LGL) leukemia. The discussion focuses on LGL leukemia as an instructive model of dysregulated apoptosis causing both malignant and autoimmune disease. Current management options and mechanisms of therapeutic response are also described.

Dr. Greer addresses whether PTCL should be treated differently from the more common diffuse large B cell lymphomas. He discusses the therapeutic options for anaplastic large cell lymphoma (ALCL), from a conservative approach for primary cutaneous ALCL to combination chemotherapy for the highly chemosensitive ALCL expressing anaplastic lymphoma kinase. He reviews therapy options for the extranodal subtypes of PTCL by drawing from series in adults, pediatrics, dermatology, and the Far East.

Primary cutaneous T-cell-rich B-cell lymphoma: clinically distinct from its nodal counterpart?

The cases of two patients with Stage IE primary cutaneous T-cell-rich B-cell lymphoma (TCRBCL) are described. In both, the lesion showed a dense infiltrate by numerous small T lymphocytes with scattered histiocytes and large atypical B-lymphoid cells. Polymerase chain reaction assays demonstrated that the B cells were monoclonal, with immunoglobulin heavy-chain gene rearrangement. No clonal rearrangements of the T-cell receptor gamma gene were observed. Both patients were disease-free at 4 months and at 5 years after therapy, respectively. Although rare, primary cutaneous T-cell-rich B-cell lymphoma appears to have a better prognosis than its nodal counterpart, with or without skin involvement.

Primary T-cell-rich B-cell lymphoma of the ethmoid sinus. A case report with 5 years of follow-up

T-cell-rich B-cell lymphoma (TCRBCL) is an uncommon and recently recognized variant of B-cell non-Hodgkin lymphoma characterized by a few large neoplastic B cells amid a predominant population of reactive T lymphocytes and variable numbers of histiocytes. Morphologically, TCRBCL resembles a variety of non-Hodgkin lymphomas and Hodgkin disease. Accurate diagnosis and proper treatment are essential to assure a favorable prognosis. To our knowledge, this is the first report of ethmoid sinus presentation of TCRBCL in an Epstein-Barr virus-negative 51-year-old man. Combined chemotherapy and radiotherapy were administered based on the correct diagnosis. The patient has had a complete response with no recurrence during the 5-year follow-up.

Lymphocyte predominance Hodgkin's disease: the use of bcl-6 and CD57 in diagnosis and differential diagnosis

Distinction of lymphocyte predominance Hodgkin's disease (LPHD) from other forms of lymphoma often requires immunohistochemistry (IHC). Most previously published recommended panels include markers to define the large neoplastic cells (for example, CD20, J chain, CD45) as well as the non-neoplastic background cells (CD21, CD45RO, CD57, TiA 1). In the present study we examine the practical use of a double IHC method designed to look simultaneously at two germinal center specific cell types: bcl6+ cells and [bc16+, CD57+] co-positive cells. All 10 nodular LPHD had bcl6+ large cells and numerous CD57+ small background cells, including [bcl6+CD57+] cells in rosettes. One case of LPHD with large cell transformation contained numerous bcl6+ large cells both singly (in areas of typical LPHD) and in sheets (in foci of large cell transformation), many CD57+ small cells but few [bcl6+CD57+] co-positive cells and no rosettes. In none of the five cases of florid progressive transformation of germinal centers were true rosettes seen, although all contained variable numbers of bcl6+ large cells and CD57+ cells. Lymphocyte-rich classic Hodgkin's disease LRCHD cases were notable for bcl6 reactivity in Reed-Sternberg cells in all cases, numerous background small bcl6+ lymphocytes, and rare CD57+ cells. Two phenotypic profiles were associated with the 10 cases of T cell-rich B cell large cell lymphoma (TCRBCL). In the first, group "A," six of six cases had bc16- large cells and few CD57+ small cells, and none had significant numbers of [bcl6+, CD57+] co-positive cells. In the second, group "B," four of four cases had bcl6+ large cells with numerous CD57+ and [bcl6+, CD57+] co-positive cells. These findings not only show that LPHD can be distinguished from its morphologic mimics through identification of specific germinal center cell types, but also identifies a second group of TCRBCL (group "B") whose phenotype suggests it might be an architectural variant of nodular LPHD.

The management of adult aggressive non-Hodgkin's lymphomas

Aggressive non-Hodgkin's lymphona include diffuse large B-cell lymphoma, anaplastic large cell lymphona, and different peripheral T-cell lymphomas. An international prognostic index has been developed including age, serum LDH, performance status, and extranodal involvement. For localized aggressive lymphoma, the preferred treatment is 3-4 CHOP and radiation therapy, with a cure rate of 70-80%. For disseminated aggressive lymphoma, current regimens have a cure rate of less than 40%. Innovative strategies, including dose escalation, autologus stem cell support, new drugs, and immunotherapy are being explored to improve these results.

The histologic classification of 602 cases of feline lymphoproliferative disease using the National Cancer Institute working formulation

Case information and histologic slides for 688 admissions of feline tissues from 12 veterinary institutions were assembled and reviewed to determine tissues obtained by biopsy or necropsy, age and sex of cat, tumor topography, feline leukemia viral antigen status, histologic frequency of mitoses, diagnosis, presence of necrosis, and presence and degree of sclerosis. Histologic sections were examined to place the lesions in one of the diagnostic categories of the National Cancer Institute working formulation (NCI WF) for lymphomas or lymphoid leukemia. Correlations between the various factors determined were tested using contingency tables and chi-square analysis to provide a statistical comparison between the levels of observations determined by case examination with the numbers expected from chance alone. Significant correlations (P < or = 0.05) were found between diagnosis and tumor topography, the frequency of mitoses, necrosis, sclerosis, and age, between mitoses and necrosis, topography, age, and feline leukemia viral infection status, between topography and necrosis and age, and between leukemia viral status and age. Significant correlations between diagnosis and tumor topography included a greater than expected number of cases of acute and chronic lymphoid leukemia and multicentric distribution of tumor. Small cell lymphomas were more frequent than expected in enteric and cutaneous areas and less frequent than expected in mediastinal, renal, and multicentric areas. In contrast, the high-grade small noncleaved type of lymphomas was found significantly more frequently than expected in the mediastinum and less frequently than expected in enteric tissues. In comparing diagnosis and frequency of mitoses, the lymphomas classified as low grade by the NCI WF were significantly more frequent than expected in the lower categories (0-2/100x) of mitoses, and those classified as high-grade lymphomas were more frequent than expected in the higher categories (4-8/1OOx) of mitoses. In comparing diagnosis and sclerosis, diffuse sclerosis was more frequent than expected for the intermediate grade lymphomas of mixed cell type and for the high-grade lymphomas of the immunoblastic polymorphous type. In comparing diagnosis and locally extensive necrosis, this feature was more frequently observed than expected for cases of intermediate grade lymphoma of the small-cleaved cell category and for the high-grade lymphoma of the immunoblastic cell type. In comparing mitoses and necrosis, the lower grade lymphomas were, in general, characterized by a lower frequency of mitoses and a lower incidence of necrosis then would be expected from chance alone. In contrast, the higher grade lymphomas were characterized by more frequent mitoses and a higher incidence of necrosis. In tests comparing mitoses and tumor topography, lymphomas of the alimentary tract were more frequently observed than expected in the category with the lowest level of mitoses (0-1/100x), whereas lymphomas of the mediastinum and kidney were more frequently observed than expected in the categories with a higher level (4-20/ 100x) of mitoses.

T-cell-rich large B-cell lymphoma in children and adolescents: a clinicopathologic report of six cases from the Children's Cancer Group Study CCG-5961

BACKGROUND

T-cell-rich large B-cell lymphoma (TCRLBCL) is a morphologic subset of diffuse large B-cell lymphoma that has been confused with Hodgkin disease and reactive lymphadenopathies. To the authors' knowledge the majority of reports of TCRLBCL are from adults, and it is not widely recognized as occurring in the pediatric population. The current study reports a cohort of six cases of TCRLBCL from the Children's Cancer Group CCG-5961 study.

METHODS

Biopsies from patients entered on CCG-5961 were submitted for central pathology review and immunophenotyping. Six cases of TCRLBCL were identified and correlated with clinical characteristics.

RESULTS

Of 86 cases centrally reviewed to date on CCG-5961, 20 (23%) were diagnosed as diffuse large B-cell lymphomas. Of these, 6 cases (7% of total cases and 30% of large B-cell cases) were TCRLBCL, based on a diffuse growth pattern with a minor population of neoplastic large B cells and an associated extensive reactive T-cell infiltrate. All patients with TCRLBCL were males ages 12-16 years. Three patients with TCRLBCL had advanced stage disease. No bone marrow or central nervous system involvement was detected in any case.

CONCLUSIONS

TCRLBCL is a morphologic subtype of diffuse large B-cell lymphoma that may be difficult to recognize due to the extensive infiltrate of reactive T cells. This entity is not well recognized in pediatric patients, but in the current study represented 7% of all cases and 30% of large B-cell lymphomas received for central review from the ongoing CCG-5961 protocol. Because TCRLBCL may be confused with Hodgkin disease and reactive lymphadenopathies, it is essential that this entity be recognized in the pediatric age group.

Primary cutaneous T-cell-rich B-cell lymphomas with flow cytometric immunophenotypic findings. Report of 3 cases and review of the literature

BACKGROUND

Primary cutaneous T-cell-rich B-cell lymphoma is a relatively rare entity that has been diagnosed most commonly using immunohistochemical and molecular techniques. Flow cytometric immunophenotyping (FCI) has not been described in this entity. We report the demonstration of B-cell monoclonality by FCI in 3 cases of primary cutaneous T-cell-rich B-cell lymphoma.

METHODS

Clinical and pathologic data were recorded for 3 cases of primary cutaneous T-cell-rich B-cell lymphoma. Immunohistochemical and FCI data were available in all cases; DNA analysis was performed in 1 case.

RESULTS

Flow cytometric immunophenotyping revealed a monoclonal B-cell population exclusively in the monocyte (large cell) region in all 3 cases. Immunohistochemistry confirmed the T-cell richness of the infiltrates within the cutaneous lymphomas; T cells accounted for 65% to greater than 90% of the cells within the infiltrates. DNA analysis by polymerase chain reaction in 1 case did not demonstrate a monoclonal rearrangement of the immunoglobulin heavy-chain gene.

CONCLUSIONS

Flow cytometric immunophenotyping in primary cutaneous T-cell-rich B-cell lymphoma may be useful in demonstrating monoclonality in these cases, especially if there is selective gating on the relatively small population of cells in the large cell region. The FCI data should be correlated with histology and immunohistochemistry.

The use of flow cytometry in the diagnosis and monitoring of malignant hematological disorders

Flow cytometry is a modality with ever increasing application in modern hematological practice. This is due to the rapidity of obtaining results, ease of use and increasing power to detect abnormal populations of cells. The major uses of flow cytometry in malignant hematology are in the diagnosis, classification and monitoring of diseases such as leukemia, lymphoma and myeloma. The technique is now used also to detect disease-specific populations of cells in paroxysmal nocturnal hemoglobinuria. This review describes the use of flow cytometry in many disease states.

Primary T-cell-rich B-cell lymphoma in the kidney presenting with acute renal failure and a second malignancy

Infiltration of the kidney is commonly found in lymphoma, but acute renal failure arising from bilateral renal infiltration is uncommon. Primary renal lymphoma may occur and is usually of B-cell lineage. It is rare for patients with lymphoma to develop acute renal failure as their initial clinical presentation. Recently, an association between primary renal lymphoma and a second primary malignancy has been reported. We describe the first case of a renal T-cell-rich B-cell lymphoma presenting as acute renal failure, which was associated with a second primary pulmonary malignancy.

T-cell-rich B-cell non-Hodgkin's lymphoma mimicking Hodgkin's disease

We report on a patient with recurrent T-cell-rich B-cell lymphoma (TCRBCL), initially misdiagnosed as a lymphocyte-rich Hodgkin's disease. This case exemplifies the diagnostic problems of TCRBCL and the need for immunophenotypic analysis to differentiate TCRBCL from Hodgkin's disease, nodular paragranuloma and peripheral T-cell lymphoma. A rather unusual aspect is the long disease-free interval between the excision of the node in and the late relapse in 1996. The significance of the abundant T-cell infiltration in this B-cell neoplasm will be discussed and the concepts concerning antitumor response will be reviewed. Based on epidemiological data and the clinical behaviour TCRBCL does not seem to represent a distinctive pathological entity.

Epstein-Barr virus related hemophagocytic syndrome in a T-cell rich B-cell lymphoma

We report the case of a 30-year-old woman who presented with an EBV related hemophagocytic syndrome. After a few months she developed a T-cell rich B-cell non-Hodgkin's lymphoma with liver involvement. Serological data demonstrated a reactivation of the EBV infection. Tumor progression with liver involvement occurred during treatment with conventional chemotherapy. Tumor reduction and disappearance of all masses was seen after starting high-dose sequential chemotherapy, followed by an autologous peripheral blood progenitor transplantation LMP-1 could be amplified in the tumor material by PCR technology, but no LMP-1 expression could be found in the few malignant B-cells with Reed-Sternberg morphology. Sequence analysis of the carboxy terminal of the LMP-1 region revealed the naturally occurring 30 bp deletion variant of the LMP-1 with multiple point mutations within the NF kb region. Since LMP-1 was not expressed in the malignant tumor cells, no evidence could be found, that EBV participated in the tumorigenesis of this case.

T-cell-rich large-B-cell lymphomas contain non-activated CD8+ cytolytic T cells, show increased tumor cell apoptosis, and have lower Bcl-2 expression than diffuse large-B-cell lymphomas

The factor(s) responsible for the reduced B cell number and increased T cell infiltrate in T-cell-rich large-B-cell lymphomas (TCRBCLs) have not been well characterized. We studied 18 TCRBCLs and 12 diffuse large-B-cell lymphomas (DLBCLs) to compare the 1) predominant T cell subpopulation(s), 2) expression of cytotoxic granule proteins (TIA-1 and granzyme B), 3) level of tumor cell apoptosis (Apoptag system, Oncor, Gaithersburg, MD), and 4) expression of Ki-67 (Mib-1) and apoptosis-related proteins (fas (CD95), bcl-2, and p53). T cells in TCRBCLs and DLBCLs were predominantly CD8+ T cells expressing alphabeta T-cell receptors and TIA-1 (16 of 18 TCRBCLs with >50% TIA-1+ small lymphocytes) but lacking granzyme B (16 of 18 TCRBCLs with <25% granzyme B+ small lymphocytes). Scattered apoptotic tumor cells (confirmed with CD20 co-labeling) were present in 15 of 18 TCRBCLs, with 14 of 15 cases having <10% apoptotic cells. No apoptotic cells were seen in 12 of 12 DLBCLs. In 16 of 16 immunoreactive TCRBCLs, <25% tumor cells were bcl-2+, whereas 6 of 12 DLBCLs had >50% bcl-2+ tumor cells. CD95 (fas) expression was also lower, with 3 of 18 (16.7%) TCRBCLs versus 4 of 12 (33%) DLBCLs having >25% CD95+ tumor cells. TCRBCLs and DLBCLs had similar levels of p53 and Ki-67 (Mib-1) expression. Thus, T cells in TCRBCLs are non-activated cytotoxic T lymphocytes (TIA-1+, granzyme B-). Tumor cell apoptosis (perhaps cytotoxic T cell mediated) may partly account for the decreased number of large (neoplastic) B cells in TCRBCLs, but other factors (ie, decreased bcl-2 expression) may also be needed.

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

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