Histopathology and immunohistochemistry of peripheral T cell lymphomas: a proposal for their classification

Comprehensive Profiling of EBV Gene Expression and Promoter Methylation Reveals Latency II Viral Infection and Sporadic Abortive Lytic Activation in Peripheral T-Cell Lymphomas

Epstein-Barr virus (EBV) latency patterns are well defined in EBV-associated epithelial, NK/T-cell, and B-cell malignancies, with links between latency stage and tumorigenesis deciphered in various studies. In vitro studies suggest that the oncogenic activity of EBV in T-cells might be somewhat different from that in EBV-tropic B lymphoid cells, prompting us to study this much less investigated viral gene expression pattern and its regulation in nine EBV+ peripheral T-cell lymphoma (PTCL) biopsies. Using frozen specimens, RT-PCR showed 6/7 cases with a latency II pattern of EBV gene expression. Analyses of EBNA1 promoter usage and CpG methylation status in these six cases showed that only Qp was used, while Cp, Wp, and Fp were all silent. However, the remaining case showed an exceptionally unique latency III type with lytic activation, as evidenced by EBV lytic clonality and confirmed by the full usage of Cp and Qp as well as weakly lytic Fp and Wp, fully unmethylated Cp and marginally unmethylated Wp. Further immunostaining of the eight cases revealed a few focally clustered LMP1+ cells in 7/8 cases, with rare isolated LMP1+ cells detected in another case. Double immunostaining confirmed that the LMP1+ cells were of the T-cell phenotype (CD3+). In 6/8 cases, sporadically scattered Zta+ cells were detected. Double staining of EBER-ISH with T-cell (CD45RO/UCHL1) or B-cell (CD20) markers confirmed that the vast majority of EBER+ cells were of the T-cell phenotype. Predominant type-A EBV variant and LMP1 30-bp deletion variant were present, with both F and f variants detected. In summary, the EBV gene expression pattern in PTCL was found to be mainly of latency II (BART+EBNA1(Qp)+LMP1+LMP2A+BZLF1+), similar to that previously reported in EBV-infected nasopharyngeal epithelial, NK/T-cell, and Hodgkin malignancies; however, fully lytic infection could also be detected in occasional cases. Rare cells with sporadic immediate-early gene expression were commonly detected in PTCL. These findings have implications for the future development of EBV-targeting therapeutics for this cancer.

Diagnosis, Risk Stratification, and Treatment of Peripheral T-Cell Lymphomas: Past and Present

Peripheral T-cell lymphomas represent an evolving class of aggressive T-cell malignancies that are generally refractory to conventional treatments and historically carry a poor prognosis. Recent advances in gene expression profiling have begun to unravel the specific molecular mechanisms of tumorigenesis in these disease processes, allowing for discrete classification schemes that help guide discussions regarding prognosis and therapy options. We outline here a review of the histopathology, epidemiology, clinical features, and treatment strategies currently used in the management of these diseases.

Advances in understanding of angioimmunoblastic T-cell lymphoma

It has been nearly half a century since angioimmunoblastic T-cell lymphoma (AITL) was characterized in the early 1970’s. Our understanding of the disease has dramatically changed due to multiple discoveries and insights. One of the key features of AITL is aberrant immune activity. Although AITL is now understood to be a neoplastic disease, pathologists appreciated that it was an inflammatory condition. The more we understand AITL at cellular and genetic levels, the more we view it as both a neoplastic and an inflammatory disease. Here, we review recent progress in our understanding of AITL, focusing on as yet unsolved questions.

Intensive Induction Therapy Compared With CHOP for Hepatosplenic T-cell Lymphoma

INTRODUCTION

Hepatosplenic T-cell lymphoma (HSTCL) is a rare peripheral T-cell lymphoma that disproportionately affects individuals with a clinical history of immunosuppression. It carries a poor prognosis, and, owing to its rarity, there is no single or well-established treatment.

PATIENTS AND METHODS

We conducted the largest-to-date individual-level meta-analysis based on literature searches to determine the best induction therapy for HSTCL. We compared response rates and survival among patients who received "non-CHOP-based" induction with regimens containing cytarabine, etoposide, and/or platinum-based treatment to those receiving treatment with CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) or CHOP-like therapy. We also review additional regimens including alemtuzumab and pentostatin, and assessed the role of consolidation with hematopoietic stem-cell transplantation (HSCT).

RESULTS

We identified 166 patients with HSTCL, 118 of whom had sufficient information on induction treatment and survival. Eighty-four patients received non-CHOP-based (N = 34) or CHOP/CHOP-like (N = 50) induction treatment. Non-CHOP-based induction was associated with a complete/partial response rate of 82% compared with 52% (P = .006) with CHOP/CHOP-like and increased median overall survival (P = .00014). Our data showed that maximum survival among patients with HSTCL was achieved with non-CHOP-based induction followed by consolidation with HSCT.

CONCLUSIONS

Non-CHOP-based induction appears superior to CHOP/CHOP-like induction in both achieving complete/partial response and durable survival. Induction therapy of HSTCL should be intensified with non-CHOP-based regimens and followed by consolidation with HSCT in eligible patients.

Approach to nodal-based T-cell lymphomas

Peripheral T-cell lymphomas (PTCLs) represent a heterogeneous group of uncommon malignancies derived from mature T cells and usually characterised by an aggressive clinical course. Their clinical presentation, localisation and pattern of dissemination are highly variable, but the majority of cases present as nodal diseases. The recently revised classification of lymphomas has incorporated many new molecular genetic data derived from gene expression profiling and next generation sequencing studies, which refine the definition and diagnostic criteria of several entities. Nevertheless, the distinction of PTCL from various reactive conditions, and the diagnosis of PTCL subtypes remains notably challenging. Here, an updated summary of the clinicopathological and molecular features of the most common nodal-based PTCLs (angioimmunoblastic T-cell lymphoma and other nodal lymphomas derived from follicular T helper cells, anaplastic large cell lymphomas and peripheral T-cell lymphoma, not otherwise specified) is presented. Practical recommendations in the diagnostic approach to nodal T-cell lymphoproliferations are presented, including indications for the appropriate use and interpretation of ancillary studies. Finally, we discuss commonly encountered diagnostic problems, including pitfalls and mimics in the differential diagnosis with various reactive conditions, and the criteria that allow proper identification of distinct PTCL entities.

Cd30-Positive Cutaneous Anaplastic Large Cell Lymphoma with Ichthyosis Acquisita

Anaplastic large cell lymphoma (ALCL) is a high-grade non-Hodgkin's lymphoma recognized by the expression of the CD30 marker and by its morphology. We report an unusual case of ALCL in a 42-year-old woman. For ten years the patient only had pruritic erythematous skin lesions, then a plaque with nodules and ulcers on the right thigh and leg developed, followed by ichthyosis acquisita. The development of ALCL in women and the association of ichthyosis acquisita with this type of lymphoma are uncommon.

CD30 Differential Staining is Useful in Classifying Lymphomas Intermediate between Hodgkin's Disease and Anaplastic Large Cell (Ki1) Lymphoma

AIMS AND BACKGROUND

The authors analyzed the BerH2 reactivity patterns of the tumor cells in 23 Hodgkin's lymphomas (HD), in 13 CD30+ anaplastic large cell (Ki1) lymphomas (ALCL), in two HD with transition to secondary CD30+ ALCL, and in six additional lymphomas intermediate between HD and ALCL.

METHODS

Paraffin blocks of formalin-fixed biopsies were immunostained. Immunostaining was modified by pronase digestion and by microwave assistance.

RESULTS

Hodgkin-Reed-Sternberg (HRS) cells of all 23 Hodgkin's lymphomas were reactive for BerH2, but the reactivity patterns differed: after pronase digestion, HRS cells of 17/23 Hodgkin's lymphomas showed exclusively or at least predominantly cytoplasmic BerH2 reactivity, whereas only four Hodgkin's lymphomas presented with prominent membrane-bound positivity. Microwave processing in 16/23 Hodgkin's lymphomas induced membrane-bound BerH2 positivity in the HRS cells; a minority of five cases retained the distinct cytoplasmic pattern. In contrast, 10/13 ALCLs were characterized by membranous reactions, independent of whether pronase or microwave pretreatment had been applied. The CD30+ ALCLs secondary to HD also showed a tendency towards membranous positivity more than did the antecedent Hodgkin's lymphomas. In the HD/ALCL borderline group, 3/6 cases revealed cytoplasmic BerH2 patterns after pronase digestion and thus were more closely related to HD, whereas 2/6 cases reacted with membranous positivity as did the genuine ALCLs of our series.

CONCLUSIONS

We conclude from these findings that the above modifications in CD30 immunostaining can be helpful in the characterization of lymphomas that constitute a continuous histomorphological as well as phenotypical spectrum between HD and ALCL.

Peripheral T-cell lymphoma, not otherwise specified

The peripheral T-cell lymphoma, not otherwise specified (PTCL, NOS) belongs to a heterogeneous class of aggressive neoplasms. Although several morphologic subtypes of this tumor have been described, no particular genetic, immunological, or distinct clinical features define this disease. Patients can experience night sweats, fever, lymphadenopathy, weight loss, splenomegaly, and/or skin changes. Common laboratory tests reveal that patients have anemia, thrombocytosis, lymphocytosis, eosinophilia, hypergammaglobulinemia, or increased lactate dehydrogenase. In this case study, a patient presented with massive lymphadenopathy and right lower limb swelling, which he developed over 6 weeks. A tissue biopsy and supporting investigations confirmed the diagnosis of PTCL, NOS.

The Microscope as a Tool for Disease Discovery-A Personal Voyage

This review reflects the trajectory of my career in hematopathology, and my personal reflections on scientific advances in the field. During the course of more than 40 years, the approach to classification of hematological malignancies has evolved from descriptive approaches, based on either cytological or clinical features, to a modern approach, which incorporates cutting-edge technologies. My philosophy has focused on defining individual diseases, an approach that can best lead to an understanding of molecular pathogenesis. To quote Carolus Linnaeus ( 1 , p. 19), the father of taxonomy, "The first step in wisdom is to know the things themselves; this notion consists in having a true idea of the objects; objects are distinguished and known by classifying them methodically and giving them appropriate names. Therefore, classification and name-giving will be the foundation of our science."

T-cell Lymphomas: Updates in Biology and Diagnosis

Nodal-based peripheral T-cell lymphomas are heterogeneous malignancies with overlapping morphology and clinical features. However, the current World Health Organization classification scheme separates these tumors into prognostically relevant categories. Since its publication, efforts to uncover the gene expression profiles and molecular alterations have subdivided these categories further, and distinct subgroups are emerging with specific profiles that reflect the cell of origin for these tumors and their microenvironment. Identification of the perturbed biologic pathways may prove useful in selecting patients for specific therapies and associating biomarkers with survival and relapse.

Controversies and Considerations in the Diagnosis of Primary Cutaneous CD4+ Small/Medium T-Cell Lymphoma

Context.—Primary cutaneous CD4+ small/medium T-cell lymphoma is a provisional and controversial entity with a broad differential diagnosis. Despite being an uncommon lymphoma, it is a frequent diagnostic consideration in cutaneous biopsies with a dense lymphoid infiltrate because it shows overlapping features with reactive lymphoid hyperplasia (pseudolymphoma) and a variety of other primary cutaneous and systemic lymphomas. However, proper classification of this process is important for determining patient prognosis and treatment options.

Objective.—To review the clinical, morphologic, immunophenotypic, and genetic features of primary cutaneous CD4+ small/medium T-cell lymphoma and contrast those features with entities in the differential diagnosis.

Data Sources.—Applicable literature will be reviewed with emphasis on current controversies and distinguishing characteristics.

Conclusions.—Although many consider primary cutaneous CD4+ small/medium T-cell lymphoma to be indistinguishable from reactive lymphoid hyperplasia/pseudolymphoma, it can be differentiated from other primary cutaneous and systemic lymphomas. Patients with solitary lesions of primary cutaneous CD4+ small/medium T-cell lymphoma generally have an excellent prognosis. Nevertheless, a subset of patients who have been reported to meet criteria for this lymphoma have followed a more-aggressive course; however, those patients show some differing clinical, morphologic, and immunophenotypic features.

Second malignancies in Hodgkin's disease: A review of the literature and report of a case with a secondary Lennert's lymphoma

A small percentage of patients treated for Hodgkin's disease are at risk of developing a second malignancy. The appearance of secondary malignancies such as leukemia, carcinoma or non-Hodgkin's lymphomas may be attributed to the mutagenic effects of chemotherapy and/or radiotherapy. Most secondary non-Hodgkin's lymphomas are of the B-cell type, but isolated cases were reportedly of a T-cell lineage. A review of the literature pertaining to the development of secondary peripheral T-cell lymphomas is presented along with the description of an additional case. The latter developed in the tonsil and was diagnosed as a Lennert's lymphoma (lymphoepithelioid T cell lymphoma)on histological and immunological grounds. This report also reviews the development of a of peripheral T-cell lymphoma described in patients following chemotherapy and/or radiotherapy for Hodgkin's disease.

Revising the historical collection of epithelioid cell-rich lymphomas of the Kiel Lymph Node Registry: what is Lennert's lymphoma nowadays?

AIMS

Lennert's lymphoma is a rare variant of peripheral T-cell lymphoma (PTCL) not otherwise specified (NOS). The aim of this study was to further characterize this tumour.

METHODS AND RESULTS

Historical material of 97 lymphomas with a high content of epithelioid cells, collected at the Kiel Lymph Node Registry were reviewed, by applying immunohistochemistry and current diagnostic criteria. Among all cases revised, various B-cell lymphoma entities (25 cases), Hodgkin lymphomas (21 cases) and PTCL subtypes (48 cases) could be identified. A distinctive subgroup of eight PTCLs was found that were regarded as genuine Lennert's lymphomas. These cases were characterized by mild atypia, a non-activated cytotoxic phenotype [TIA1 cytotoxic granule-associated RNA binding protein (TIA1)-positive(+) and granzyme B-negative], and a substantial lack of follicular T-helper (T(FH) ) cell markers. Among the other PTCLs, including angioimmunoblastic T-cell lymphoma and PTCL NOS, many cases with positivity for more than three T(FH) cell-associated molecules were recorded.

CONCLUSIONS

Our study shows that, according to current criteria, Lennert's lymphoma is a rare but distinctive entity among epithelioid cell-rich lymphomas, differing on grounds of morphology and immunophenotype from other PTCL subtypes. An additional finding is the broad morphological spectrum of epithelioid-cell rich PTCLs showing a T(FH) cell phenotype.

Nodular lymphocyte-predominant hodgkin lymphoma with atypical T cells: a morphologic variant mimicking peripheral T-cell lymphoma

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a distinct Hodgkin lymphoma subtype composed of few neoplastic lymphocyte-predominant (LP) cells in a background of reactive small B and T cells. We have seen occasional NLPHL cases that contain background T cells with prominent cytologic atypia, raising the differential diagnosis of peripheral T-cell lymphoma not otherwise specified (PTCL-NOS) or a composite lymphoma. We sought to characterize the clinicopathologic features of such cases. Eleven NLPHL cases with atypical T cells diagnosed from 1977 to 2010 were identified at 2 institutions and compared with 24 control NLPHL cases lacking atypical T cells. All 9 male patients and 2 female patients presented with localized peripheral lymphadenopathy. In comparison with control patients, they were younger (median age, 13.8 vs. 36.1 y; P=0.015), with more frequent cervical lymph node involvement (54.5% vs. 8.3%, P=0.015). In all 11 cases, areas of NLPHL with typical B-cell-rich nodules containing LP cells were present. Nine cases contained sheets of atypical T cells surrounding primary and secondary follicles in a pattern mimicking the T-zone pattern of PTCL-NOS; the remaining 2 cases contained atypical T cells presented as large clusters at the periphery of B-cell-rich nodules. In all cases, the atypical T-cell-rich areas contained rare scattered LP cells, which were IgD in 5 of 7 cases (71.4%). The atypical T cells showed no pan-T-cell antigen loss or aberrant T-cell antigen expression in any case, and polymerase chain reaction or Southern blot analysis showed no evidence of T-cell clonality in 6 cases tested. The atypical T cells exhibited a variable immunophenotype with respect to germinal center, follicular T-helper, T-regulatory, and cytotoxic T-cell markers. Among 8 patients with clinical follow-up (median follow-up: 6.4 y), 5 patients had recurrent NLPHL at 6 months to 12 years after diagnosis and 6 patients are alive without disease at 9 months to 18 years after diagnosis. In comparison with control patients, NLPHL patients with atypical T cells were more likely to develop recurrent NLPHL (71.4% vs. 13.6%, P=0.008) and to have a shorter time to relapse (P=0.04). Our findings suggest that some cases of NLPHL, occurring predominantly in younger patients, contain prominent populations of morphologically atypical T cells that may raise the possibility of concurrent nodal involvement by PTCL-NOS, a rare diagnosis in children. The clinical behavior of these cases appears similar to that of NLPHL with T-cell-rich diffuse areas, with a higher risk of disease recurrence and no difference in overall survival; however, this finding warrants confirmation in studies of larger numbers of patients.

Diagnosis of Nodal Peripheral T-Cell Lymphomas

Lymph node-based peripheral T-cell lymphomas are rare and exhibit a morphologic spectrum that overlaps with reactive lymphoid hyperplasia, B-cell lymphomas, and Hodgkin lymphoma, presenting a diagnostic challenge. This review focuses on the major categories of lymph node-based peripheral T-cell lymphomas recognized by the 2008 World Health Organization Classification of Tumours of Haematopoietic and Lymphoid Tissues. Diagnostic strategies for approaching T-cell neoplasms using a combined clinical, morphologic, immunophenotypic, and genetic approach are presented. Practical information to aid in distinguishing peripheral T-cell lymphomas from other hematologic malignancies and benign conditions is provided.

Epstein-Barr virus positive anaplastic large cell lymphoma: myth or reality?

The World Health Organization (WHO) Classification of Tumours of Haematopoietic and Lymphoid Tissue, 2008 edition, states that anaplastic large cell lymphoma (ALCL) is "consistently negative for Epstein-Barr virus (EBV)". The statement made by the WHO has led to the widespread belief that EBV can have no pathogenic role in ALCL. Herein we report a case of an immunocompetent 35-year-old male who presented with hemophagocytic syndrome secondary to lymphoma for which diagnostic material consisted solely of a bone marrow biopsy. The biopsy demonstrated large anaplastic cells which were uniformly positive for surface CD3, CD30 (strong membranous and Golgi expression), CD45, TIA-1 and Granzyme B but negative for ALK-1. In-situ hybridization was strongly positive for EBER in the large neoplastic cells. The uniformity of CD30 expression and positivity for cytotoxic markers on the anaplastic tumor cells raised the diagnostic possibility of an EBV-associated ALCL, ALK-. Discussion of this case as well as a retrospective review of 64 cases of reported of EBV+ ALCL are presented.

Hepatitis B virus reactivation after a resolutive acute hepatitis leading to a diagnosis of T cell lymphoma

A case of hepatitis B virus reactivation leading to the diagnosis of a T cell lymphoma is reported. A 66-year-old woman with a past history (10 years before) of spontaneously recovered acute hepatitis B (with disappearance of serum hepatitis B surface antigen and appearance of anti-HBs), has been referred for hepatologic consultation for acute hepatitis. The patient was found positive again for hepatitis B surface antigen as well HBeAg and hepatitis B virus DNA. No other cause of liver disease was identified and a diagnosis of spontaneous hepatitis B virus reactivation was made. Five months later a peripheral T cell lymphoma was diagnosed. This unusual case confirms that natural immunity is not protective against hepatitis B virus reactivation and shows that such hepatitis B virus reactivation may precede the usual clinical manifestations of a peripheral T cell lymphoma.

Array comparative genomic hybridization analysis of PTCL-U reveals a distinct subgroup with genetic alterations similar to lymphoma-type adult T-cell leukemia/lymphoma

PURPOSE

Peripheral T-cell lymphoma, unspecified (PTCL-U) comprises histopathologically and clinically heterogeneous groups. The purpose of this study was to identify subgroups with distinct genetic, histopathologic, and prognostic features.

EXPERIMENTAL DESIGN

We used array comparative genomic hybridization (CGH) for high-resolution analysis of 51 PTCL-U patients and the array data for examining possible correlations of histopathologic and clinical features. Moreover, we compared the genetic, histopathologic, and prognostic features of the PTCL-U cases with those of 59 cases of lymphoma-type adult T-cell leukemia/lymphoma (ATLL).

RESULTS

We identified 32 regions with frequent genomic imbalance, 1 region with high copy number gain at 14q32.2, and 1 region with homozygous loss at 9p21.3. Gains of 7p and 7q and loss of 9p21.3 showed a significant association with poor prognosis. PTCL-U cases with genomic imbalance showed distinct histopathologic and prognostic features compared with such cases without alteration and a marked genetic, histopathologic, and prognostic resemblance to lymphoma-type ATLL.

CONCLUSIONS

The array CGH enabled us to identify the frequently altered genomic regions with strong prognostic power among PTCL-U cases. A correlative analysis using the array CGH data disclosed a subgroup in PTCL-U with genomic alterations and with histopathologic and clinical relevance. In addition to histopathologic similarity, the strong genetic and prognostic resemblance between PTCL-U cases with genomic imbalance detected by array CGH and lymphoma-type ATLL seems to support the notion that the former may constitute a distinct PTCL-U subgroup.

Peripheral T-cell lymphoma with follicular T-cell markers

INTRODUCTION

Peripheral T-cell lymphomas (PTCLs) in western countries are uncommon tumors with unfavorable prognosis. They may be subclassified as anaplastic large-cell lymphomas (ALCLs), angioimmunoblastic-T-cell lymphomas (AITLs), or unspecified peripheral T-cell lymphomas (PTCLs-U). It has recently been demonstrated that AITLs originate from germinal center follicular helper T cells (TFH), whereas the normal counterparts of other PTCLs remain essentially unknown. The aim of this study was to establish whether other PTCL subgroups also express TFH cell markers.

MATERIALS AND METHODS

One hundred forty-six PTCLs were analyzed for programmed death-1 (PD-1) expression in tissue microarrays using a new monoclonal antibody called NAT-105. PD-1-positive cases, which did not fulfill all the criteria for AITL, were further evaluated in whole-tissue sections for another 12 immunohistochemical markers, including the TFH cell markers CXCL13, CD10, and BCL6. Clonal Ig and T-cell receptor rearrangements and Epstein-Barr virus-encoded RNA expression were also evaluated. Morphologic, clinical, and follow-up data were reviewed.

RESULTS

Twenty-five out of 87 non-AITL cases (28.75%) showed PD-1 immunostaining. CXCL13, BCL6, and CD10 expression was found in 24/25 (96%), 16/25 (64%), and 6/25 (24%) cases, respectively. All cases expressed at least 2 TFH cell markers. Moreover, 5 cases were positive for all 4 markers. Most cases (17/25, 68%) displayed some AITL-like features. Of the remainder, 1 was considered to be early AITL, 1 was diagnosed as ALCL-anaplastic lymphoma kinase-negative, and 4 of the other 6 PTCLs-U had morphology consistent with lymphoepithelioid (Lennert's) lymphoma. Three AITL-like cases showed IgH clonal rearrangement, 2 of which were associated with Epstein-Barr virus expression. Our series of patients did not differ significantly in their clinical presentation from most reported PTCL cases in the literature: 55% of them were alive and 35% were in complete remission after a median follow-up of 15 months after cyclophosphamide, dexorubicin, vincristine, and prednisone-based chemotherapy.

CONCLUSIONS

TFH cell markers, especially PD-1, were expressed in a subset of PTCLs not classified as AITL, although most of them shared some morphologic features with AITL. This suggests that the spectrum of AITL may be wider than previously thought, possibly including cases of lymphoepithelioid (Lennert's) lymphoma. Additionally, the results suggest that a subgroup of PTCLs-U, distinct from AITL and including some cases denominated as ALCL, may also be derived from TFH cells, although they develop along a distinct pathogenic pathway.

Association of high proliferation in adult T-cell leukemia cells with apoptosis, and expression of p53 protein in acute type ATL

Proliferation, apoptosis and p53 protein expression in adult T-cell leukemia (ATL) cells were investigated. Twenty peripheral blood tissue specimens (PBTS) comprising 7 cases of acute type ATL, 7 cases of chronic type ATL and 6 other leukemias were examined by means of antigen retrieval and the polymer method employing anti-Ki67 antigen (MIB-1), anti-cleaved caspase-3, anti-single stranded DNA and three kinds of anti-p53 protein antibodies including DO7. Most acute and chronic cases of ATL included more than 10% MIB-1-positive proliferating leukemia cells and more than 1% cleaved caspase-3-positive apoptotic cells. Some cells which were positive for both MIB-1 and anti-cleaved caspase-3 antibody were observed in acute type ATL. Nuclear deposition of p53 protein labeled by DO7 was often found in acute type (p < 0.05). Within the medium-sized population of ATL cell nuclei, DO7-positive ATL cells had a smaller nuclear area factor (long axis x short axis) than DO7-negative ATL cells. A few proliferating ATL cells entered apoptosis, and the appearance of a subclone of ATL cells with nuclear deposition of p53 protein labeled by DO7 characterized acute type.

Angioimmunoblastic T-cell lymphoma

Angioimmunoblastic T-cell lymphoma (AITL) is a rare and aggressive neoplasm clinically characterized by sudden onset of constitutional symptoms, lymphadenopathy, hepatosplenomegaly, frequent autoimmune phenomena, particularly hemolytic anemia and thrombocytopenia, and polyclonal hypergammaglobulinemia. The lymph node histological picture is also distinctive, constituted by a polymorphic infiltrate, a marked proliferation of high endothelial venules, and a dense meshwork of dentritic cells. The neoplastic CD4+ T-cells represent a minority of the lymph node cell population; its detection is facilitated by the aberrant expression of CD10. Almost all cases arbor an EBV infected B-cell population. Patients with AITL have a poor prognosis with conventional treatment, with a median overall survival of less than 3 years. Patients achieving a good clinical response seem beneficiate from a consolidation with high-dose therapy and autologous stem cell transplantation. Constitutional symptoms and autoimmune phenomena, and some times also the neoplastic masses may respond to immunosuppressive or immunomodulatory agents such as thalidomide.

Peripheral T-cell lymphomas, unspecified (or not otherwise specified): a review

Peripheral T-cell lymphomas (PTCL) comprises a heterogeneous group of haematological tumours, which originate from mature T-cells, and constitute less than 15% of all non-Hodgkin's lymphomas (NHLs) in adults. The current WHO classification recognizes nine distinct clinicopathologic peripheral T-cell NHLs, being the 'unspecified variant' (PTCL-U) the most common subtype. These neoplasms often present in advanced stage at diagnosis, and most commonly have an aggressive clinical course requiring prompt treatment. The rarity of these tumours requires additional studies to better understand their biology and search for new therapies which may hopefully improve the dismal outcome of most patients. This review aims to describe the pathobiological aspects as well the clinical characteristics and current therapeutic strategies of the PTCLs, with special attention to the group of PTCL-U.

c-Maf expression in angioimmunoblastic T-cell lymphoma

The oncogene c-Maf was recently found to be overexpressed in approximately 50% of multiple myeloma cases, and a role for c-Maf in promoting cyclin D2 expression has been postulated. We previously examined c-Maf expression in various T-cell lymphomas by reverse-transcription polymerase chain reaction and found extremely elevated c-Maf levels in angioimmunoblastic T-cell lymphoma (AILT). In this study, we examined T-cell lymphomas for c-Maf and cyclin expression immunohistochemically. Of 93 cases of T-cell lymphomas we investigated in the current study, c-Maf expression was seen in 23 out of 31 cases of AILT, 3 out of 11 of adult T-cell leukemia/lymphoma, 4 out of 19 of peripheral T-cell lymphoma, unspecified [PTCL(U)], and 0 out of 11 cases of mycosis fungoides, 0 out of 11 of anaplastic large cell lymphoma, and 1 out of 10 of extranodal NK/T-cell lymphoma, nasal type. Double immunostaining in AILT revealed that the majority of c-Maf-positive cells were also positive for CD43 (MT1), CD45RO (UCHL-1), and CD4 but were negative for CD20 (L26). Additionally, cyclins D1 and D2, which stimulate cell cycle progression, were overexpressed in a large number of the c-Maf-positive AILT samples. Quantitative reverse-transcription polymerase chain reaction analysis also showed that c-Maf was overexpressed in 8/31 cases of AILT, 0/19 cases of PTCL(U), 0/11 cases of anaplastic large cell lymphoma, 0/10 cases of extranodal NK/T-cell lymphoma, nasal type, and 2/8 cases of multiple myeloma, presenting significant difference between AILT and PTCL(U) (P=0.016, chi test). These findings strongly suggest that CD4-positive neoplastic T cells in AILT show c-Maf expression and provide new insight into the pathogenesis of AILT suggesting c-Maf to be a useful diagnostic marker for AILT.

Identification of a Proliferation Signature Related to Survival in Nodal Peripheral T-Cell Lymphomas

Purpose

Nodal peripheral T-cell lymphomas (PTCLs) constitute a heterogeneous group of neoplasms, suggesting the existence of molecular differences contributing to their histologic and clinical variability. Initial expression profiling studies of T-cell lymphomas have been inconclusive in yielding clinically relevant insights. We applied DNA microarrays to gain insight into the molecular signatures associated with prognosis.

Materials and Methods

We analyzed the expression profiles of 35 nodal PTCLs (23 PTCLs unspecified and 12 angioimmunoblastic) using two different microarray platforms, the cDNA microarray developed at the Spanish National Cancer Centre and an oligonucleotide microarray.

Results

We identified five clusters of genes, the expression of which varied significantly among the samples. Genes in these clusters seemed to be functionally related to different cellular processes such as proliferation, inflammatory response, and T-cell or B-cell lineages. Regardless of the microarray platform used, overexpression of genes in the proliferation signature was associated significantly with shorter survival of patients. This proliferation signature included genes commonly associated with the cell cycle, such as CCNA, CCNB, TOP2A, and PCNA. Moreover the PTCL proliferation signature showed a statistically significant inverse correlation with clusters of the inflammatory response (P < .0001), as well as with the percentage of CD68+ cells.

Conclusion

Our findings indicate that proliferation could be an important factor in evaluating nodal PTCL outcome and may help to define a more aggressive phenotype.

Fine needle aspiration cytology of high grade T-cell lymphomas in human T-lymphotropic virus type 1 carriers

We studied the fine needle aspiration (FNA) cytology of high grade peripheral T-cell lymphomas from eight human T-lymphotropic virus-1 (HTLV-1) positive patients. FNA smears from seven lymphomas showed a distinctive cytologic pattern with a dominance of rounded cells with irregular nuclei and a moderately basophilic cytoplasm. Irregular cells with a pale abundant cytoplasm were present in varying amounts. Some smears contained a few giant cells with cerebriform nuclei. In addition, plasma cells and eosinophils were found. Epithelioid cells were an inconstant finding. On histology these seven lymphomas were assigned to the pleomorphic medium-large cell subtype and all but one were of T-helper phenotype with rearrangements of the T-cell receptor. FNA smears from a lymph node in a patient with a previous histological diagnosis of lymphomatoid papulosis of the gingiva showed a monotonous pattern of large immunoblastic cells with some binucleated variants consistent with a diagnosis of high grade immunoblastic lymphoma, which was confirmed histologically. Our results show that peripheral T-cell lymphomas from HTLV-1 positive patients have cytological patterns which are distinctive enough to allow a conclusive diagnosis of high grade T-cell lymphoma. However, we do not think that the cytology of HTLV-1 positive lymphomas can be differentiated from that of virus-unrelated high grade T-cell lymphomas.

Gene expression analysis of peripheral T cell lymphoma, unspecified, reveals distinct profiles and new potential therapeutic targets

Peripheral T cell lymphoma, unspecified (PTCL/U), the most common form of PTCL, displays heterogeneous morphology and phenotype, poor response to treatment, and poor prognosis. We demonstrate that PTCL/U shows a gene expression profile clearly distinct from that of normal T cells. Comparison with the profiles of purified T cell subpopulations (CD4+, CD8+, resting [HLA-DR-], and activated [HLA-DR+]) reveals that PTCLs/U are most closely related to activated peripheral T lymphocytes, either CD4+ or CD8+. Interestingly, the global gene expression profile cannot be surrogated by routine CD4/CD8 immunohistochemistry. When compared with normal T cells, PTCLs/U display deregulation of functional programs often involved in tumorigenesis (e.g., apoptosis, proliferation, cell adhesion, and matrix remodeling). Products of deregulated genes can be detected in PTCLs/U by immunohistochemistry with an ectopic, paraphysiologic, or stromal location. PTCLs/U aberrantly express, among others, PDGFRalpha, a tyrosine-kinase receptor, whose deregulation is often related to a malignant phenotype. Notably, both phosphorylation of PDGFRalpha and sensitivity of cultured PTCL cells to imatinib (as well as to an inhibitor of histone deacetylase) were found. These results, which might be extended to other more rare PTCL categories, provide insight into tumor pathogenesis and clinical management of PTCL/U.

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

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

Gene expression profiling identifies molecular subgroups among nodal peripheral T-cell lymphomas

The classification of peripheral T-cell lymphomas (PTCL) is still a matter of debate. To establish a molecular classification of PTCL, we analysed 59 primary nodal T-cell lymphomas using cDNA microarrays, including 56 PTCL and three T-lymphoblastic lymphoma (T-LBL). The expression profiles could discriminate angioimmunoblastic lymphoma, anaplastic large-cell lymphoma and T-LBL. In contrast, cases belonging to the broad category of 'PTCL, unspecified' (PTCL-U) did not share a single molecular profile. Using a multiclass predictor, we could separate PTCL-U into three molecular subgroups called U1, U2 and U3. The U1 gene expression signature included genes known to be associated with poor outcome in other tumors, such as CCND2. The U2 subgroup was associated with overexpression of genes involved in T-cell activation and apoptosis, including NFKB1 and BCL-2. The U3 subgroup was mainly defined by overexpression of genes involved in the IFN/JAK/STAT pathway. It comprised a majority of histiocyte-rich PTCL samples. Gene Ontology annotations revealed different functional profile for each subgroup. These results suggest the existence of distinct subtypes of PTCL-U with specific molecular profiles, and thus provide a basis to improve their classification and to develop new therapeutic targets.

Linfoma cutâneo de células B: relato de caso

Os linfomas cutâneos são classificados em linfomas de células B ou de células T, sendo os primeiros menos freqüentes. O linfoma cutâneo de células B (LCCB) pode ser primário ou secundário, tendo o último história natural mais agressiva, com pior prognóstico. Os autores apresentam um caso de LCCB secundário com três anos de evolução, curso indolente, sem envolvimento de outros órgãos além da pele, com ótima resposta ao tratamento quimioterápico. A distinção entre LCCB primário e secundário é muito difícil de ser realizada, uma vez que eles são clínica e histopatologicamente indistinguíveis. Deve-se sempre pesquisar o acometimento de órgãos internos para então definir o prognóstico.

Nodal peripheral T-cell lymphomas and, in particular, their lymphoepithelioid (Lennert?s) variant are often derived from CD8+ cytotoxic T-cells

Nodal peripheral T-cell lymphomas are not well understood, and most of them are classified in the "not otherwise specified group" (PTCL-NOS). Data on their normal cellular derivation are ambiguous. Most peripheral T-cell lymphomas are composed of tumor cells and a (sometimes dominant) reactive background, which also includes resting and activated T-lymphocytes. We defined the phenotype of the tumor cells in 101 PTCL-NOS based on their cytological atypia and using immunohistochemical double stains on paraffin sections with CD4/Ki67 and CD8/Ki67. The results were correlated to clinical presentation and outcome. Lineage could be defined in 98 cases (97%). Tumor cells were CD4(+) in 43 cases and CD8(+) in 38. These presented at a younger age but a higher clinical stage compared with the CD4(+) lymphomas. In 15 cases, the atypical cells were CD4(-)CD8(-); two cases were CD4(+)CD8(+). Of 17 lymphoepithelioid (Lennert's) lymphomas, 15 expressed CD8, one each was CD4(+) and CD4(-)CD8(-).

Phenotypic analysis of peripheral T/NK cell lymphoma: study of 408 Japanese cases with special reference to their anatomical sites

The World Health Organization (WHO) classification of malignant lymphoma presented a list of disease entities well defined by clinical, immunological and genetic features. Therefore, the current diagnosis of peripheral T/NK-cell lymphomas (PTNKLs) essentially requires the inclusion of anatomical sites of disease and phenotypical features. We analyzed 408 Japanese cases of PTNKLs in order to clarify the relationship between anatomical sites of disease and phenotypical features and to translate the functional subsets of T and NK cells into their diagnoses for further understanding lymphomatic biology. The T/NK-cell lymphoma entities were allocated into three categories: (i) cytotoxic memory T-cell and/or NK-cell lymphoma (n = 151) consisting of extranodal NK/T-cell tumors other than mycosis fungoides (MF); (ii) non-cytotoxic memory T-cell lymphoma (n = 142) consisting of nodal and cutaneous tumors such as angioimmunoblastic T-cell lymphoma, adult T-cell lymphoma/leukemia and MF; and (iii) anaplastic lymphoma kinase positive anaplastic large cell lymphoma (n = 110) that has unique features and might be regarded as cytotoxic 'naive' T-cell lymphoma. Overall, these three categories were significantly correlated with age of onset, anatomical sites, the level of expression of cytotoxic molecules and CD45RO, and association with Epstein-Barr virus. This concept might provide a new insight enabling further understanding of the interrelationships among WHO T/NK-cell disease entities.

CD30 (Ki-1)-positive large-cell cutaneous T-cell lymphoma with secondary xanthomatous changes after radiation therapy

A 72-year-old woman with a large mass on her forehead was found to have primary cutaneous CD30-positive large T-cell lymphoma and was treated with radiation therapy. Five weeks after the completion of radiation therapy, a large, yellow plaque developed on the forehead. Histopathologic examination showed numerous xanthoma-like cells with clear and foamy cytoplasm that infiltrated the upper and mid dermis with no residual lymphoma. To our knowledge, this is the first report of xanthomatous change after radiation therapy for primary cutaneous CD30-positive large cell lymphoma. We believe that the xanthomatous change after radiation therapy probably was caused by lysis of radiosensitive lymphoma cells and histiocytic scavenging of lipid-membrane debris.

Rare occurrence of CD30+ circulating cells in patients with cutaneous CD30+ anaplastic large cell lymphoma: a study of nine patients

BACKGROUND

The presence of a significant percentage of circulating atypical lymphocytes in peripheral blood has already been demonstrated in systemic CD30+ anaplastic large cell lymphoma (ALCL), which implies that a leukaemic component may be present in this subset of lymphomas. However, no similar data are available for the cutaneous counterpart of this particular lymphoproliferation.

OBJECTIVES

To assess the presence of atypical cells, CD30+ lymphocytes and of a dominant T-cell clone in peripheral blood in a series of patients with cutaneous CD30+ ALCL.

MATERIALS AND METHODS

Nine patients with either primary (four) or secondary (five) cutaneous CD4+ CD30+ ALCL were selected. The percentage of CD30+ CD4+ lymphocytes among peripheral blood mononuclear cells (PBMC) was determined by flow cytometry and the presence of a dominant circulating T-cell clone was assessed by polymerase chain reaction targeting the T-cell receptor gamma chain. A control group composed of apparently healthy individuals was similarly studied at the same time.

RESULTS

The mean percentage of CD30+ cells in PBMC was slightly higher in patients than in controls (3.9% vs. 2.7%) but the difference was not statistically significant. Only two patients displayed more than 5% CD30+ cells, both of whom had a minor tumour burden. A dominant circulating T-cell clone was detected in only three cases, including these two latter patients.

CONCLUSIONS

The occurrence of a significant percentage of CD30+ CD4+ circulating cells is rare in active cutaneous CD30+ ALCL, either primary or secondary. This percentage is not related to the apparent skin tumour burden but a significant figure appeared to be correlated with the detection of a dominant T-cell clone in peripheral blood. Overall, these data show that, unlike mycosis fungoides, peripheral blood involvement seems infrequent in cutaneous CD30+ ALCL. The hypothesis that a high percentage of CD30+ circulating cells might be related to the presence of a cryptic systemic disease cannot be ruled out.

Angioimmunoblastic T cell lymphoma is derived from mature T-helper cells with varying expression and loss of detectable CD4

Angioimmunoblastic T cell lymphoma (AILT) is a rare lymphoma that is regarded as a clinicopathologic entity but shows considerable histomorphologic diversity, variable immunophenotypes and inconsistent T cell receptor (TCR) gene rearrangement. One hundred four paraffin blocks of AILT were investigated defining tumor cell lineage by triple immunostains with a confocal laser scanning microscope and correlating morphology, immunophenotype and TCRgamma gene rearrangement to clinical outcome. Ninety-nine cases were CD4(+), some of them showing a mixture of CD4(+) and CD4(-) tumor cells. The remaining 5 specimens were CD3(+)/CD4(-)/CD8(-). A considerable number of T cells of different subtypes could always be found, but even in 13 cases predominated by CD8(+) cells, proliferation could be attributed to atypical CD4(+) cells. TCRgamma gene rearrangement was monoclonal in 48 cases (69%) among 70 tested. In 29 of these semi-quantitative gene scan analysis resulted in a median proportion of monoclonal peak of 35% of PCR-products. Clinical outcome was identical grouping patients by clonality of TCRgamma, absence or presence of clear cell clusters and international prognostic index. We conclude that AILT is mainly derived from CD2(+)CD3(+)CD4(+)CD5(+)CD7(-) mature T-helper cells with varying expression and partial loss of detectable CD4. A significant number of non-neoplastic T cells (resting CD4(+) T cells and activated small or medium-sized CD8(+) lymphocytes) may coexist with a minor neoplastic T cell population. Clinicopathologic correlation suggests AILT to be a well defined homogeneous entity with poor prognosis. Currently no prognostic factors can be derived.

Adult T-cell leukemia/lymphoma in Jujuy, north-west Argentina

Human T-cell leukemia virus type 1 (HTLV-1) infection is prevalent in native Americans living in the Andes. Some of their malignant lymphomas (ML) show a peculiar histology suggestive of adult T-cell leukemia/lymphoma (ATLL). To determine whether ML resembling ATLL are indeed ATLL, re-analysis of 34 cases occurring in Jujuy, a province of Argentina, was conducted, concentrating on immunological phenotype, integration of HTLV-1 proviral DNA, expression of HTLV-1 p40Tax and p27Rex, and infection of Epstein-Barr virus (EBV). The ML were 22 cases of mature peripheral T-cell and natural killer (NK)-cell neoplasm (mT/NKN), 11 B-cell malignant neoplasms and one Hodgkin's lymphoma. Polymerase chain reaction against the HTLV-1 proviral DNA, using DNA extracted from paraffin sections, indicated integration of the HTLV-1 proviral DNA in three cases of eight mT/NKN. Two other cases of mT/NKN were positive for anti-HTLV-1 antibodies. Expression of p40Tax and p27Rex was detected in all five of these mT/NKN cases associated with HTLV-1. As such, these five mT/NKN were rediagnosed as ATLL. In situ hybridization signals for EBV-encoded small nuclear early region-1 were detected in nine cases of mT/NKN, of which five cases of NK-cell lymphoma were found to have cytoplasmic CD3 expression, a CD56 phenotype and positivity of TIA1. According to the new World Health Organization classification, the mT/NKN class includes five cases of ATLL and five cases of NK-cell lymphomas. The five cases of ATLL were of native American extraction from an HTLV-1-endemic area around Jujuy, north-west Argentina.