T-cell lymphoma: morphology, immunophenotype and clinical features

Approach to Cutaneous Lymphoid Infiltrates: When to Consider Lymphoma?

Cutaneous lymphoid infiltrates (CLIs) are common in routine dermatopathology. However, differentiating a reactive CLI from a malignant lymphocytic infiltrate is often a significant challenge since many inflammatory dermatoses can clinically and/or histopathologically mimic cutaneous lymphomas, coined pseudolymphomas. We conducted a literature review from 1966 to July 1, 2015, at PubMed.gov using the search terms: Cutaneous lymphoma, cutaneous pseudolymphoma, cutaneous lymphoid hyperplasia, simulants/mimics/imitators of cutaneous lymphomas, and cutaneous lymphoid infiltrates. The diagnostic approach to CLIs and the most common differential imitators of lymphoma is discussed herein based on six predominant morphologic and immunophenotypic, histopathologic patterns: (1) Superficial dermal T-cell infiltrates (2) superficial and deep dermal perivascular and/or nodular natural killer/T-cell infiltrates (3) pan-dermal diffuse T-cell infiltrates (4) panniculitic T-cell infiltrates (5) small cell predominant B-cell infiltrates, and (6) large-cell predominant B-cell infiltrates. Since no single histopathological feature is sufficient to discern between a benign and a malignant CLI, the overall balance of clinical, histopathological, immunophenotypic, and molecular features should be considered carefully to establish a diagnosis. Despite advances in ancillary studies such as immunohistochemistry and molecular clonality, these studies often display specificity and sensitivity limitations. Therefore, proper clinicopathological correlation still remains the gold standard for the precise diagnosis of CLIs.

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.

Identification of the tumor cells in peripheral T-cell lymphomas by combined polymerase chain reaction-based T-cell receptor beta spectrotyping and immunohistological detection with T-cell receptor beta chain variable region segment-specific antibodies

Most nodal peripheral T-cell lymphomas (PTCL) originate from alphabeta-T cells, and they often contain reactive T cells that may hamper immunophenotyping. To specifically identify the neoplastic population in immunohistochemically stained slides, we assessed the heterogeneity of the T-cell receptor beta chain variable region (TCRVbeta). This region contains 65 gene segments, of which only one is expressed after rearrangement. To investigate PTCL, we developed a polymerase chain reaction assay to define the clonally rearranged TCRVbeta segment. Detecting the corresponding epitope with segment-specific antibodies enabled identification of tumor cells among the T cells. The TCRVbeta segment of the tumor cells was defined in 13 of 13 PTCL not otherwise specified and 11 of 13 angioimmunoblastic T-cell lymphomas. Antibodies corresponding to the respective TCRVbeta segment of the tumor were available for seven cases from each group. After applying these antibodies in combination with antibodies against CD3, CD5, CD4, CD8, and cytotoxic molecules, double stains were evaluated by confocal laser scanning microscopy. In 9 of 14 cases, less than 50% of T cells expressed the clonally rearranged TCRVbeta segment. Phenotypes defined in double stains differed from those obtained by conventional immunohistochemistry in 11 of 14 cases. The combination of TCRVbeta polymerase chain reaction and immunohistochemistry may facilitate more reliable detection and characterization of tumor cells in PTCL.

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(-).

T-zone lymphoma with cutaneous involvement: a case report and review of the literature

T-zone lymphoma (TZL) is a rare subtype of nodal peripheral T-cell lymphoma characterized by a clonal expansion of T-zone lymphocytes accompanied by a proliferation of other T-zone constituents. Non-specific cutaneous alterations are seen in about one-third of all cases, but specific cutaneous involvement is extremely rare. We present a case of TZL with secondary skin infiltration, review the literature on cutaneous manifestations of TZL and discuss the differential diagnosis of TZL.

Peripheral T-cell lymphoma (excluding anaplastic large-cell lymphoma): results from the Non-Hodgkin's Lymphoma Classification Project

BACKGROUND

Peripheral T-cell lymphoma (PTCL) is rare in most parts of the world. Therefore, we have evaluated the 96 cases of PTCL diagnosed within the Non-Hodgkin's Lymphoma Classification Project (NHLCP) (1378 cases) for their geographical distribution, pathologic features and diagnostic reliability, as well as clinical presentation and outcome.

MATERIALS AND METHODS

Diagnoses of all cases were rendered independently by five experienced hematopathologists based on morphology only, and after introduction of the immunophenotype and clinical data. Divergent diagnoses were jointly discussed and a final consensus diagnosis was established in each case. Reliability of the diagnoses was evaluated statistically, and the clinical features and outcome were analyzed according to the consensus diagnoses.

RESULTS

Seven per cent of all non-Hodgkin's lymphoma (NHL) cases reviewed were classified as PTCL and the frequency varied from 1.5% to 18.3% in different countries. The interobserver agreement with the consensus diagnosis of PTCL was 86% in the Revised European-American Lymphoma (REAL) classification, but the designation of subtypes was less reliable. Diagnostic reliability improved from 41% to 86% after immunophenotyping, but did not improve further with the addition of detailed clinical data. Clinically, angiocentric nasal lymphoma presented in young females (median age 49 years) at extranodal sites, but with few adverse risk factors, whereas angioimmunoblastic lymphoma presented most often in older males (median age 65 years) at nodal and extranodal sites with numerous risk factors. The 5-year overall and failure-free survivals for patients with PTCL treated with doxorubicin (Adriamycin)-containing regimens were only 26% and 20%, respectively. Both failure-free and overall survival were strongly correlated with the performance status and International Prognostic Index scores at presentation, but differences in survival were not observed between the major histological types. However, within the PTCL 'not otherwise specified' category, but not angioimmunoblastic lymphoma, the number of transformed blasts was prognostically relevant.

CONCLUSIONS

PTCLs can be diagnosed reliably by experienced hematopathologists, but immunophenotyping is absolutely necessary. Currently, all types of PTCL should be considered high-grade lymphomas. An increased ability to distinguish T-lymphocyte subsets is needed in order to better subclassify the PTCLs for therapeutic and prognostic purposes.

Diagnosis of lymphoma in paraffin wax sections by nested PCR and immunohistochemistry

AIMS

To investigate whether nested polymerase chain reaction (PCR) and immunohistochemistry can be used to diagnose malignant lymphoma.

METHODS

Paraffin wax embedded tissue sections from 31 patients with malignant lymphoma were analysed by nested PCR and immunohistochemistry using standard protocols.

RESULTS

Nested PCR amplification of 1 pg DNA confirmed monoclonality in B cell lymphoma; PCR amplification of 10 pg DNA confirmed monoclonality in T cell lymphoma. Twenty seven (87%) samples were diagnosed as malignant lymphoma by nested PCR, and 24 (77%) by immunohistochemistry. Seven samples were diagnosed as malignant lymphoma by nested PCR, but not by immunohistochemistry, whereas the use of both procedures gave a diagnosis of malignant lymphoma in all 31 samples.

CONCLUSIONS

A combination of immunohistochemistry and nested PCR can be used to diagnose malignant lymphoma in routine paraffin wax embedded sections.

Massive cutaneous large cell T-cell non-Hodgkin's lymphoma of the pinna

We report a patient with a cutaneous large cell T-cell non-Hodgkin's lymphoma of the pinna, a condition that has not been reported before. Despite the large dimensions of the tumour, the patient's ear was restored by electron therapy.

Small cell pleomorphic T-cell lymphoma presenting with cutaneous vasculitis

The association between cutaneous vasculitis and lymphoproliferative disease has been increasingly recognized. We report a female patient who presented with cutaneous vasculitis which was due to a small cell pleomorphic T-cell lymphoma. In spite of aggressive therapy, she died two years after onset of disease. The clinical picture of vasculitis associated with lympho-proliferative disease is addressed with particular emphasis on symptoms and signs suggesting malignancy rather than vasculitis appearing in concert with well-defined connective tissue disorders.

Morphological characteristics of malignant T-cell lymphomas in baboons

Fifteen cases of generalized peripheral T-cell non-Hodgkin's lymphoma in baboons were phenotyped immunologically and morphologically. Using the updated Kiel classification the cases included low-grade and high-grade lymphomas and low-grade lymphomas that had transformed into high-grade lymphomas. In the low-grade group there were seven cases of lymphocytic type, partly corresponding to chronic lymphocytic leukaemia of T type and to T-zone lymphoma in man. In addition there were four cases of prolymphocytic-lymphocytic type, which show large nodules ("proliferation centres") and which have no equivalent in the Kiel classification. In four cases there was a progression to an immunoblastic lymphoma and in one case to a large cell anaplastic lymphoma. In addition, three cases of large cell anaplastic lymphoma without a low-grade component were found. Both the immunoblastic lymphomas and the large cell anaplastic lymphomas corresponded well with the same types in the Kiel classification. The cases of large cell anaplastic lymphoma were also CD30 positive. Most of these lymphomas were CD4 positive, but there were rare cases that were either CD8 positive, showed both CD4 and CD8 positivity or had lost both antigens. Antigens associated with cell activation were often revealed. All but one baboon had antibodies in the blood against the retrovirus STLV-1 (simian T-cell leukaemia virus 1), which is very similar to human T-cell leukaemia virus 1 (HTLV-1) in man. Despite this virological resemblance, the morphology of these T-cell lymphomas does not resemble that of the HTLV-1-positive Japanese T-cell lymphomas but is like that of the HTLV-1-negative European cases.

Baboon T cell lymphomas expressing the B cell-associated surface proteins CD40 and Bgp95

Papio hamadryas baboons in the Sukhumi colony develop enzootic outbreaks of malignant lymphomas with an incidence of about 1.5% per year among adults of the high-risk stock. We investigated the surface phenotypes of cells from normal and lymphomatous animals using antibodies against human lymphocyte antigens. We found that more than 80% of the lymphomas that developed during the last 3 years were characterized histologically to be of the peripheral T cell type. Generally, the lymphomatous cells also expressed high levels of MHC class II DR protein, CD18 (LFA-1 beta chain), and CD45RO. Surprisingly, these cells also expressed on their surface two proteins previously characterized as being relatively B cell-restricted: CD40 and Bgp95. These proteins were never found on the peripheral blood T cells from normal animals. The expression of these two gene products was confirmed by RNA blotting and immunoprecipitation. In most cases, the two B cell-associated proteins were expressed on the predominant T cell subsets; we found both B cell proteins on CD4+, CD8+ as well as on the CD4/8 double-positive cells when these subsets were expressed at high levels. About 90% of these animals are seropositive for Herpesvirus papio and human T cell leukemia virus-1 (HTLV-1) before developing outright lymphomas. In all of the lymphoma samples, HTLV-1 tax DNA sequences were detected by PCR amplification. Whether or not HTLV-1 or the Herpesvirus papio gene products influence the surface expression of CD40 and Bgp95 remains to be determined.

Phenotyping of T-cell lymphomas in paraffin sections--which antibodies?

Five antibodies, MT1 (CD43), UCHL1 (CD45RO), OPD4, poly-CD3 and beta F1, were assessed for their reactivity with 50 archival cases of T-cell lymphoma in formalin-fixed paraffin-embedded tissue. All cases had been previously characterized as T-cell lymphomas, and the histological types included 14 cases of small cerebriform lymphoma, six cases of angioimmunoblastic lymphadenopathy-like T-cell lymphoma, four cases of T-zone lymphoma, five cases of pleomorphic small cell lymphoma, 12 cases of pleomorphic medium and large cell lymphoma, four cases of anaplastic large cell lymphoma, two cases of T-lymphoblastic lymphoma and three cases of enteropathy-associated T-cell lymphoma. UCHL1 and MT1 showed reactivity with the highest percentage of cases (94 and 86% respectively) but lack absolute specificity for T-cells, especially in high-grade lymphomas. Poly-CD3 is highly specific for T-cells, and stained neoplastic cells in almost 80% of the cases. beta F1 stained the lowest percentage of cases (40%). UCHL1 and poly-CD3 together identified 98% of cases, and this combination is recommended for the diagnosis of T-cell lymphomas in paraffin sections.

Quantitative study of KI-67 antibody staining in 46 T-cell malignant lymphomas using image analysis

Image analysis with a SAMBA 2005 (ALCATEL-TITN, Co) was used to quantify the Ki-67 stained area percentage in 46 T-cell malignant lymphomas (T-ML), classified according to the updated Kiel classification. This parameter demonstrated correlation with the number of Ki-67-positive cellular profiles (r = 0.88, P less than 0.001) and was more reproducible than cell counting. A significant difference was found between low and high grade T-ML (mean values +/- SEM respectively of 10.20 +/- 1.82 per cent and 25.63 +/- 3.15 per cent). The most interesting findings were that: (1) AILD-type T-ML showed an intermediate proliferation rate (15.55 +/- 2.72 per cent) between pleomorphic T-ML with medium and with large cells (respectively 12.53 +/- 3.64 per cent and 22.43 +/- 3.46 per cent), both of which belong to the high grade malignancy group. This finding is in accordance with the poor prognosis of this subtype despite its classification in the low grade malignancy group. (2) Subclassification of the pleomorphic MLs according to the predominance of small, medium or large cells, demonstrated significant differences between these three subtypes. However, the great overlap of values between pleomorphic T-ML with medium and with large cells, seems to indicate that the subclassification of these two subtypes is less valid. (3) A wide range of values with overlap was observed in AILD-type ML, in pleomorphic with medium or large cells and in lymphoblastic T-ML: for these T-ML with variable survival courses, the Ki-67 area percentage, one parameter of proliferative activity, appears worth studying as a prognostic factor.

Deleted HTLV-I provirus in blood and cutaneous lesions of patients with mycosis fungoides

Mycosis fungoides, a rare form of cutaneous T cell leukemia/lymphoma, is suspected of having a viral etiology on the basis of certain similarities to adult T cell leukemia, which is associated with human T cell leukemia/lymphoma virus type I (HTLV-I) infection. Cell lines were established from peripheral blood mononuclear cells (PBMC) of an HTLV-I-seronegative patient with mycosis fungoides. DNA hybridization analysis revealed the presence of HTLV-I-related sequences with unusual restriction endonuclease sites. Sequence analysis of subcloned fragments demonstrated the presence of a monoclonally integrated provirus with a 5.5-kilobase deletion involving large regions of gag and env and all of pol. Additional evidence for the presence of deleted proviruses was found by polymerase chain reaction (PCR) amplification of DNA from cutaneous lesions of five other HTLV-I-seronegative patients. The findings suggest that HTLV-I infection may be involved in the etiology of at least certain cases of mycosis fungoides.

Immunohistological analysis of the immunoreactivity of normal lymphoid cells and lymphomas with the monoclonal antibody OPD4

OPD4 is a recently described monoclonal antibody that recognizes a fixation-resistant 200 kD antigen restricted to a subset of T cells. Immunolabelling with OPD4 in paraffin sections of normal lymphoid tissues and cases of malignant lymphoma was compared with that of other antibodies in common use, including the T-cell restricted antibodies MT1 and UCHL1 and the B-cell restricted antibodies MB1, F8-11-13, and L26. OPD4 showed similar immunoreactivity to UCHL1 in normal tissues. OPD4 did not stain Reed-Sternberg cells in Hodgkin's disease. In non-Hodgkin's lymphomas, OPD4, like UCHL1, reacted with only 2/22 B-cell lymphomas. OPD4 was, however, less useful as a marker of T-cell lymphomas, staining only 11/32 cases, while UCHL1 stained 22/32 cases. We conclude that OPD4 is not a useful antibody for the routine diagnosis of T-cell lymphoma.

Bone marrow histologic and immunohistochemical findings in peripheral. T-cell lymphoma: A study of 38 cases

The histologic and immunohistochemical findings in bone marrow (BM) biopsies from 38 patients with peripheral T-cell lymphoma (PTCL) are reported. Routine light microscopy showed that BM involvement was unequivocal in 12 cases and questionable in 14 cases. There was no histologic evidence of lymphoma in the remaining 12 cases. Immunohistochemistry performed on BM frozen sections demonstrated the T-cell origin of the infiltrating lymphoid cells in 24 of the 26 patients with unequivocal or questionable involvement. The malignant nature of these cells was suggested by demonstration of an aberrant T-cell phenotype identical to that observed in the other sites of involvement. In addition, in four of the 12 cases with apparently normal BM at routine light microscopy, immunohistochemistry revealed a minimal but phenotypically abnormal T-cell population, suggesting mild infiltration by lymphoma. These combined histologic and immunohistochemical data documented a high incidence (73%) of BM involvement by PTCL. In addition, a very peculiar sinusal pattern of BM involvement was found in five patients who presented an unusual type of hepatosplenic T-cell lymphoma expressing the gamma delta T-cell receptor. The present study demonstrates the high incidence of BM involvement by PTCL and emphasizes the value of frozen section immunohistochemistry to establish this diagnosis, especially when routine light microscopy findings are questionable.

Angiocentric immunoproliferative lesion/T-cell non-Hodgkin's lymphoma and the acquired immune deficiency syndrome: a case report and review of the literature

The lesions known as lymphocytic vasculitis, polymorphic reticulosis (midline malignant reticulosis, lethal midline granuloma), lymphomatoid granulomatosis, and angiocentric lymphoma form what have been collectively termed the angiocentric immunoproliferative lesions (AIL). Because of recent reports demonstrating clonal rearrangements of the T-cell receptor in these lesions, the AIL are now thought to represent a continuous spectrum of post-thymic T-cell non-Hodgkin's lymphoma (NHL). NHL associated with the acquired immune deficiency syndrome (AIDS) represents intermediate or high-grade B-cell malignancies in HIV-infected patients that may be etiologically related to the Epstein-Barr virus (EBV). There have been reports of EBV-associated T-cell NHL, AIL, and large granular lymphocyte (LGL) proliferations, as well as HIV-associated T-cell neoplasia, LGL/T-cell proliferations, and AIL. We describe a case of polymorphic reticulosis (lethal midline granuloma) arising in an HIV-infected individual, who later progressed to AIDS, and review the literature on HIV-associated and EBV-associated T-cell neoplasia, LGL/T-cell proliferations, and AIL. The etiology of this AIL/T-cell NHL, especially in relation to EBV and HIV, is discussed.

Demonstration of clonality in T-cell lymphoma using an anti-T-cell receptor variable region antibody panel

Frozen sections from 35 T-cell lymphomas were stained with the Diversi-T alpha beta T-Cell Receptor panel which includes seven antibodies to T-cell receptor variable region gene products. In five cases a monoclonal population of T-cells could be demonstrated (one case V beta 5+, three cases V beta 8+ and one case V beta 6+) and in a further case a biclonal population (V beta 5+ and V beta 8+). We conclude that this antibody panel is of limited usefulness for the demonstration of clonality in T-cell lymphoma.

Peripheral T-cell lymphomas: a clinicopathologic study of 75 cases

Seventy-five peripheral T-cell lymphomas (PTLs) were classified according to the recently proposed "Updated Kiel Classification of Non-Hodgkin's Lymphomas" (mycosis fungoides and Sezary's syndrome excluded). Thirty-seven PTLs belonged to the low-grade category (T-cell chronic lymphocytic leukemia [T-CLL], 3; lymphoepithelioid, 4; angioimmunoblastic, 22; T-zone, 6; pleomorphic small cell, 2) and 38 belonged to the high-grade category (pleomorphic medium and large cell, 24; immunoblastic, 1; large-cell anaplastic Ki-1-positive, 13). Loss of pan-T antigens occurred exclusively in high-grade PTLs; on paraffin sections UCHL 1 was slightly more sensitive than MT 1. Sixty patients presented with lymphadenopathy and 15 patients (20%) presented with extranodal disease most frequently affecting the skin and upper aerodigestive tract. B-cell lymphoma symptoms were found in 43 cases (57%) and bone marrow involvement (T-CLL excluded) was found in 12 cases (17%). Staging (T-CLL excluded) revealed stage I in 13%, stage II in 15%, and stages III and IV in 72% of the cases. Among the intensively treated patients, 37% achieved complete remission and 15 are still in complete remission after 4 to 79 months (median: 24 months). The overall median survival (MS) rate was 23 months. Peripheral T-cell lymphoma of pleomorphic medium and large-cell type was the most aggressive lymphoma (MS: 8 months). B-cell lymphoma symptoms, bone marrow involvement, and Ki-67 positivity 60% or greater significantly shortened survival times, whereas age (under 60 versus over 60 years), stage (I and II versus III and IV), and grade had no significant influence. Ki-67 reactivity was found to be a prognostic factor which allows prediction of probable poor outcome, especially in cases with limited stage of disease.

Immunoblastic T-cell lymphoma presenting as an eyelid tumor

A 59-year-old white man presented with an ulcerating mass of the left upper eyelid of 6 months' duration. A biopsy specimen of the tumor was diagnosed as an immunoblastic T-cell malignant lymphoma. The lesion completely regressed after 4000 cGy of cobalt-60 radiation therapy. In the ensuing 33 months, multiple, widespread skin nodules of the same neoplasm developed including a right upper eyelid tumor. To the authors' knowledge, this is the first reported case of an immunoblastic T-cell lymphoma initially manifesting as an eyelid neoplasm.

Analysis of T-cell receptor and immunoglobulin gene rearrangements in the diagnosis of Hodgkin's and non-Hodgkin's lymphoma

The results of genotypic analysis of 29 cases of malignant lymphoma are reported and the application of this technique for differentiating between Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) is evaluated. Five cases with a differential diagnosis which included HD and NHL were analysed. These results are compared with those obtained for six B-cell NHLs, nine T-cell NHLs, and nine cases of HD. This report suggests that gene rearrangement analysis is useful in some cases in which the differential diagnoses includes HD and NHL as the absence of gene rearrangements is more consistent with a diagnosis of HD than of NHL. Two monoclonal antibodies reactive with the variable region of T-cell receptor beta-chain and molecular probes to the relevant variable region genes were used to assist in the diagnosis of T-cell lymphoma. This report confirms that genotypic analysis is useful diagnostically when the results are assessed in the context of the histopathological findings.

Variable expression of leucocyte-common (CD45) antigen in CD30 (Ki1)-positive anaplastic large-cell lymphoma: implications for the differential diagnosis between lymphoid and nonlymphoid malignancies

Monoclonal antibodies (mAbs) directed against the leucocyte common (CD45) antigen have been proposed as a useful tool for the differential diagnosis between malignant lymphomas (CD45+) and poorly differentiated nonhemopoietic tumors (CD45-). Thanks to the availability of mAbs directed against fixative-resistant epitopes of the CD45 molecule, this distinction can now easily be made even in routinely processed tissues. However, a small percentage of morphologically poorly defined neoplasms are difficult to diagnose even with the help of immunohistochemistry. The investigators report that 63 out of 165 anaplastic large-cell (ALC) lymphomas did not show any reactivity for the CD45 antigen in paraffin sections. In routine biopsies, the lymphomatous nature of these cases, most of which had been sent for consultation, could be always unequivocally established by demonstrating negativity for cytokeratins (mAb KL1) and clear dot-like and/or surface reactivity with the Ber-H2 mAb, which is directed against a fixative-resistant epitope of the lymphoid cell activation antigen CD30. Strikingly, 54% of the CD45-cases reacted with mAbs directed against fixative-resistant epitopes of the T cell-restricted CD45RO antigen (mAb UCHL1) or the B-restricted molecules CD45RA (mAb 4KB5) and L26 (unclustered). In order to avoid confusion of ALC lymphomas with anaplastic nonlymphoid tumors, pathologists must be aware of the existence of CD30+/CD45- ALC lymphomas, as they can mimic the above-mentioned malignancies both morphologically (due to the sinusoidal growth pattern) and phenotypically (due to the expression of EMA). The investigators conclude that the combined use of mAbs directed against fixative-resistant epitopes of the CD30, CD45RO, CD45RA, and L26 antigens and cytokeratins is essential for the correct diagnosis and treatment of these equivocal cases.

Prognostic significance of activation and differentiation antigen expression in B-cell non-Hodgkin's lymphoma

Immunophenotyping shows heterogeneity of expression of activation and differentiation antigens in B-cell non-Hodgkin's lymphoma (NHL). To investigate whether antigen expression correlates with clinical behaviour we have studied the clinical presentation and follow-up of a series of 111 B-cell lymphomas previously phenotyped for a panel of antigens including CD groups 5, 9, 10, 21, 23, 25, 30, 38, 4F2 antigen, and transferrin receptor. CD antigens 5, 10, and 23 were expressed significantly more often by low grade lymphomas whereas CD38, 4F2 antigen, and transferrin receptor were more often expressed by high grade lymphomas. There was a significant correlation with survival and age, stage at presentation, histological grade, and expression of 4F2 antigen and transferrin receptor but not with the other antigens studied. 4F2 antigen and transferrin receptor may identify a poor prognostic group of cases in low grade lymphoma but we conclude that phenotyping B-cell NHL for many of the antigens expressed at various stages of B-cell differentiation and activation does not provide clinically useful information in addition to that obtained from standard histological classifications.

Diagnosis of T-cell lymphoma using beta F1, anti-T-cell receptor beta chain antibody

The reactivity of a new monoclonal antibody to the T-cell beta chain antigen receptor (beta F1) with routinely processed paraffin sections from patients with T-cell lymphoma is described. Staining of tumour cells was seen in 36/47 cases of T-cell lymphoma. No staining was seen in any cases of B-cell lymphoma (0/21 cases), nine of which had previously been shown to react with other T-cell antibodies (MT1/UCHL1). We conclude that beta F1 is a specific marker for demonstrating a T-cell histogenesis of lymphoma and with advantages over other currently available antibodies reactive with paraffin sections.

Lymphoma phenotyping in formalin-fixed and paraffin wax-embedded tissues: II. Profiles of reactivity in the various tumour types

Recently, monoclonal antibodies capable of phenotyping malignant lymphomas in routinely fixed and processed tissue have become available. Some of these reagents identify lineage-restricted variants of the leucocyte common molecule, whereas others identify unique fixation-resistant epitopes on lymphoid cells, some of which are shared by non-lymphoid tissues. A new generation of antibodies recognizing 'classical' leucocyte antigens such as CD3 are also emerging. Refinements in antigen detection systems, especially for immunoglobulin recognition, combined with these new reagents promise to improve the accuracy of lymphoma diagnosis in routine histopathology. These new antibodies are reviewed, and their limitations, cross reactivities and profiles of staining in lymphoreticular disease are discussed. A strategy for their optimal use is proposed.