Analysis of beta, gamma, and delta T-cell receptor genes in lymphomatoid papulosis: cellular basis of two distinct histologic subsets

Lymphomatoid papulosis: an update and review

Lymphomatoid papulosis (LyP) is a benign chronic often relapsing skin condition that belongs to the CD30-positive cutaneous lymphoproliferative disorders. LyP typically presents as crops of lesions with a tendency to self-resolve, and morphology can range from solitary to agminated or diffuse papules and plaques to nodules or tumours. The clinical-histological spectrum can range from borderline cases to overlap with primary cutaneous anaplastic cell lymphoma (pcALCL). Histology and immunophenotype commonly show overlap with other CD30-positive disorders and sometimes may be identical to pcALCL, making its diagnosis more difficult. Patients with LyP have an increased risk of developing a second neoplasm such as mycosis fungoides, pcALCL and/or Hodgkin lymphoma. Clinical correlation allows its proper classification and diagnosis, which is fundamental for treatment and prognosis. This review focuses on the clinical appearance, histopathological features, diagnosis, differential diagnosis and management of LyP.

TCR-γ expression in primary cutaneous T-cell lymphomas

Primary cutaneous γδ T-cell lymphomas (PCGD-TCLs) are considered a subgroup of aggressive cytotoxic T-cell lymphomas (CTCLs). We have taken advantage of a new, commercially available antibody that recognizes the T-cell receptor-γ (TCR-γ) subunit of the TCR in paraffin-embedded tissue. We have analyzed a series of 146 primary cutaneous T-cell lymphomas received for consultation or a second opinion in the CNIO Pathology Department. Cases were classified according to the World Health Organization 2008 classification as mycosis fungoides (MF; n=96), PCGD-TCLs (n=5), pagetoid reticulosis (n=6), CD30(+) primary cutaneous anaplastic large cell lymphomas (n=5), primary cutaneous CD8 aggressive epidermotropic CTCLs (n=3), primary cutaneous CTCL, not otherwise specified (n=4), and extranodal nasal-type NK/T-cell lymphomas primarily affecting the skin or subcutaneous tissue (n=11). Sixteen cases of the newly named lymphomatoid papulosis type D (LyP-D; n=16) were also included. In those cases positive for TCR-γ, a further panel of 13 antibodies was used for analysis, including TIA-1, granzyme B, and perforin. Clinical and follow-up data were recorded in all cases. Twelve cases (8.2%) were positive for TCR-γ, including 5 PCGD-TCLs, 2 MFs, and 5 LyP-Ds. All 5 PCGD-TCL patients and 1 MF patient died of the disease, whereas the other MF patient and all those with LyP-D were alive. All cases expressed cytotoxic markers, were frequently CD3(+)/CD8(+), and tended to lose CD5 and CD7 expressions. Eight of 12 and 5 of 11 cases were CD30(+) and CD56(+), respectively. Interestingly, 5/12 TCR-γ-positive cases also expressed TCR-BF1. All cases analyzed were negative for Epstein-Barr virus-encoded RNA. In conclusion, TCR-γ expression seems to be rare and is confined to cytotoxic primary cutaneous TCLs. Nevertheless, its expression is not exclusive to PCGD-TCLs, as TCR-γ protein can be found in other CTCLs. Moreover, its expression does not seem to be associated with bad prognosis by itself, as it can be found in cases with good and bad outcomes.

Detection of clonal rearrangement of T-cell receptor genes in the diagnosis of primary cutaneous CD30+lymphoproliferative disorders

BACKGROUND

Detection of clonality has been reported to be a helpful tool in the diagnosis of cutaneous lymphomas. Monoclonal rearrangement of T-cell receptor genes (TCR) was reported in fresh frozen tissue of lymphomatoid papulosis (LyP) and primary cutaneous anaplastic large-cell lymphoma (ALCL), but the diagnostic value of T-cell clonality in formalin-fixed, paraffin-embedded biopsies has so far not been assessed.

METHODS

Detection of clonal rearrangement of TCRgamma genes by highly sensitive polymerase chain reaction-based automated high-resolution fragment analysis (AHRFA) in archival LyP (n = 18) and ALCL (n = 17) tissue.

RESULTS

Detection of clonality differed significantly among the histologic forms of LyP as well as between LyP and ALCL with clonality found in none of the 10 biopsies of LyP type A and B, in 4/8 (50%) of the LyP type C specimens, and in 11/17 (65%) of ALCL cases.

CONCLUSIONS

T-cell clonality can only be found in a minority (four of 18; 22%) of archival LyP specimens, even when employing a highly sensitive detection method and is thus of limited diagnostic value. Final diagnosis of LyP has to be based mainly on clinical, histologic, and immunohistochemical findings rather than on results of clonality studies.

Pathobiology of CD30+ cutaneous T-cell lymphomas

CD30+ cutaneous lymphoproliferative disorders include lymphomatoid papulosis (LyP) and anaplastic large cell lymphoma (ALCL). LyP is associated with development of lymphoma in nearly 20% of patients. Herein is reviewed the clonal relationship of LyP to malignant lymphoma, the concept of a common stem cell for LyP and associated lymphomas, and the role of genetic instability in lymphomagenesis. The possible role of the CD30+ cell as a regulatory T-cell is introduced and a model for progression of LyP to ALCL is illustrated.

Single-cell analysis of CD30+ cells in lymphomatoid papulosis demonstrates a common clonal T-cell origin

Lymphomatoid papulosis (LyP) represents an intriguing cutaneous T-cell lymphoproliferative disorder with a histologic appearance resembling malignant lymphoma. This finding strongly contrasts with the benign clinical course of the disease. However, in 10% to 20% of cases, LyP can precede, coexist with, or follow malignant lymphoma. In these cases, the same T-cell population has been shown to be present in the LyP as well as in the associated lymphoma. In most LyP cases, there is-despite the sometimes extremely long course of the disease-no evolution of a secondary lymphoma. The investigation of these uncomplicated LyP cases for the presence of clonal T-cell receptor rearrangements has produced heterogeneous results. This might be explained by biologic or technical reasons arising from analyzing whole tissue DNA extracts. To definitively clarify whether the large atypical CD30(+) cells in LyP without associated lymphoma all belong to the same clone or represent individually rearranged T cells, we analyzed the T-cell receptor-gamma rearrangements of single CD30+ as well as of single CD30- cells isolated from 14 LyP lesions of 11 patients. By using this approach we could demonstrate that the CD30+ cells represent members of a single T-cell clone in all LyP cases. Moreover, in 3 patients the same CD30+ cell clone was found in anatomically and temporally separate lesions. In contrast, with only a few exceptions, the CD30- cells were polyclonal in all instances and unrelated to the CD30+ cell clone. Our results demonstrate that LyP unequivocally represents a monoclonal T-cell disorder of CD30+ cells in all instances.

Evidence that an identical T cell clone in skin and peripheral blood lymphocytes is an independent prognostic factor in primary cutaneous T cell lymphomas

The monoclonality of the T cell receptor gamma-chain gene was analyzed by polymerase chain reaction in skin and blood specimens of 85 patients with cutaneous T cell lymphomas including 67 mycosis fungoides, seven Sézary syndromes, and 11 CD30- nonepidermotropic cutaneous T cell lymphomas. A cutaneous T cell clone was detected in 69% of mycosis fungoides and 100% of Sézary syndromes. This frequency varied according to the clinical stage: 57% in early stages (Ia-IIa) to 96% in advanced stages (IIb-IV, Sézary syndrome). A peripheral blood T cell clone was detected in 42% of early stages and in 74% of late stages but was identical to the cutaneous one in 15% and in 63%, respectively. A significant association between initial clinical stage and T cell monoclonality was observed. In nonepidermotropic cutaneous T cell lymphomas, T cell monoclonality was detected in 55% of skin and 36% of blood samples. Univariate and multivariate analyses showed that, besides the initial clinical stage, an identical cutaneous and blood T cell clone was an independent prognostic factor for disease progression of mycosis fungoides/Sézary syndrome (hazard ratio 3.4, 95% confidence interval 1.4-9.9). Parallel polymerase chain reaction study of skin and blood specimens may therefore provide an initial prognostic marker that could help to monitor therapeutic strategies. A fully prospective study, with simultaneous therapeutic trials, needs to be done to confirm our findings and to include treatment variables in the statistical analysis.

Critical review of lymphomatoid papulosis of the oral cavity with case report

A 60-year-old woman was referred to the Department of Dental Medicine at Long Island Jewish Medical Center for evaluation of multiple lesions of the tongue. She reported a long history of recurrent papular cutaneous eruptions that waxed and waned. A biopsy specimen of one of the cutaneous lesions was diagnosed as lymphomatoid papulosis. Sporadic, recurrent oral ulcers that resolved spontaneously were noted 10 to 14 days before the initial visit. These ulcers had recurred for the past 17 years. The most recent oral lesion was an erythematous, irregular, solitary ulcerated area on the middle third dorsum of tongue. The area quickly enlarged, ultimately developing extensive surface necrosis. Shortly after, a similar lesion on the posterior dorsum of the tongue developed. Biopsy specimens of the former lesion showed numerous, large, atypical, pleomorphic, and hyperchromatic cells with abundant mitoses. The large, atypical cells were immunohistochemically proven to be T lymphocytes. A diagnosis of lymphomatoid papulosis was made. Two weeks later, the tongue lesions had spontaneously and totally resolved. The clinical, histomorphologic, and immunohistochemical features, as well as gene rearrangement studies of this rare entity, are presented.

Autocrine growth regulation of CD30 ligand in CD30-expressing Reed-Sternberg cells: distinction between Hodgkin's disease and anaplastic large cell lymphoma

Persistent expression of high levels of CD30 in Hodgkin's Reed-Sternberg (H-RS) cells and anaplastic large-cell lymphoma (ALCL) cells, but not in most T- or B-cell lymphomas, suggests the presence of an underlying mechanism leading to the abnormality and possible involvement of CD30 in the growth and survival of these two unique types of tumors. In this study, we examined the effect of CD30 ligand (CD30L) on CD30-positive H-RS and ALCL cells in long-term cultures or in primary cultures. CD30L induced various degrees of proliferation in three long-term cultured H-RS cell lines (L428, HDLM-2, and KM-H2) as well as in primary cultures of H-RS cells obtained directly from patients with Hodgkin's disease. In contrast, significant inhibition was observed in one of the ALCL cell lines (SU-DHL-1), but no growth inhibition or promotion in responding to exogenous CD30L was detected in three others (PB-1, JB-6, and McG-2), nor in primary cultures of ALCL cells. Expression of CD30L was determined by polymerase chain reaction in long-term cultured cells and by an immunohistochemical method in H-RS or ALCL cells de novo in tissue sections. None of the H-RS and ALCL cell lines was positive for CD30L. In tissue sections, we noticed that ALCL cells were generally CD30L-negative. In contrast, the anti-CD30L antibody reacted with a majority of H-RS cells with diffuse cytoplasmic staining. Most H-RS cells were CD30-positive, indicating co-expression of CD30 and CD30L in the majority of lymphoma cells. The persistent high levels of CD30 and CD30L expression in H-RS cells suggest that the autocrine CD30L-CD30 cytokine-receptor loop, in addition to having the paracrine activity previously thought to exist, could play important roles in the proliferation of H-RS cells. In contrast, the CD30L-mediated cytotoxicity may participate in the regression or slow progression of ALCL during the early phase of the disease in selected patients. However, when the disease progresses, the ALCL cells are likely to become resistant to exogenous CD30L.

Regional lymphomatoid papulosis: a report of four cases

Lymphomatoid papulosis (LyP) is a chronic self-healing cutaneous eruption which is clinically benign but histologically malignant. Lesions occur episodically over the trunk and limbs. We describe four patients with regional LyP. All were male, with a range in age at onset from 12 to 47 years. In all cases, lesions were confined to a segmental unilateral area. Two patients had type A and two type B LyP. We have long-term follow-up on one patient whose lesions were limited to the right buttock for more than 20 years before more widespread lesions developed. Another patient with lesions on the left flank had mycosis fungoides limited to the same region. Only one other case of LyP presenting in a regional distribution has previously been described.

T-cell receptor gene analysis in the diagnosis of Sézary syndrome

Diagnosing Sézary syndrome (SS) on clinicopathological grounds alone is far from straightforward, particularly in the early stages of the disease. Atypical lymphocytes may be seen in the peripheral blood of patients with reactive forms of erythroderma, so additional criteria are needed to establish the diagnosis of a T-cell leukemia/lymphoma. A wide variety of confirmatory tests have been proposed in the literature, but there has been no systematic attempt to compare the specificity and sensitivity of these different methods. Recent data indicate that T-cell receptor (TCR) gene analysis is the most useful test currently available and that methods based on polymerase chain reaction are more sensitive than Southern blot analysis. We propose that the diagnostic criteria for SS should include erythroderma, atypical circulating mononuclear cells, and evidence of a clonal T-cell population in the peripheral blood. Clonality can be established with certainty by cytogenetic or TCR gene analysis, but only the latter is sufficiently sensitive to be of value in routine diagnosis. Immunophenotypic data showing an expanded CD4(+)/CD7(-) population, an elevated CD4/CD8 ratio, or restricted V beta expression are not specific to T-cell malignancy and should not be used as a sole diagnostic criteria in SS. Entry criteria for future clinical studies will need to be more rigorous if meaningful comparisons are to be made between different treatment options.

A case of lymphomatoid papulosis occurred simultaneously with Ki-1-positive anaplastic large cell lymphoma

Lymphomatoid papulosis (LyP) is a chronic self-healing skin eruption that is clinically benign but histologically mimics a malignant lymphoma. However, lymphomatoid papulosis with anaplastic large cell lymphoma responds poorly to medical treatments, including chemotherapies. We experienced a 60-year-old male patient with lymphomatoid papulosis occurred simultaneously with relapsed Ki-1-positive anaplastic large cell lymphoma who was treated with salvage chemotherapy but, unfortunately, failed to be rescued. We report it with a review of the literature.

Management of cutaneous lymphoma

The foregoing underlines the advances which have been made in our understanding of cutaneous lymphoma and the areas where further research is needed. With a few noteable exceptions the aim of therapy in CTCL is palliative rather than curative and treatment success is measured in terms of disease-free interval. There is still no evidence that any chemotherapeutic regimen prolongs survival. A possible exception is the effect of photopheresis in Sézary syndrome but our own experience differs from that in the USA and underlines the need to identify patients with clonal disease when defining subjects for study. The combination of genotypic analysis and new treatment methods offers exciting new prospects in the management of patients with cutaneous lymphoma.

Lymphomatoid papulosis and cutaneous CD30+ lymphoma

Lymphomatoid papulosis and cutaneous CD30+ lymphoma are closely related conditions in which large atypical lymphocytes that have similar immunophenotypic features occur. In lymphomatoid papulosis, the lesions are papules and nodules that spontaneously involute. There are two polar histologic patterns, type A and B, in which the large atypical cells resemble those of Hodgkin's disease and mycosis fungoides, respectively, but in many cases, features of both types are present, either separately or in the same lesions. Variants of lymphomatoid papulosis include cases with a perifollicular distribution and those with lymphocytic vasculitis or dermal mucin deposits. Clinical lesions that tend to be stable, a monomorphous cellular composition, and in the case of immunocompromised patients, the presence of Epstein-Barr viral genome characterize cutaneous CD30+ lymphoma. A loss of response to transforming growth factor-beta, which normally dampens cellular proliferation, may differentiate CD30+ lymphoma from lymphomatoid papulosis.

The dominant T cell clone is present in multiple regressing skin lesions and associated T cell lymphomas of patients with lymphomatoid papulosis

This study was undertaken to determine the clonality of lymphomatoid papulosis (LyP), its clonal relationship to lymphomas, which occur at high frequency in LyP patients, and to define the cell lineage of Reed-Sternberg-like cells in type A lesions of LyP. Punch biopsies of skin of 11 adult patients with LyP were analyzed for morphologic subtype of LyP, surface antigens, and clonal T-cell receptor (TCR) gene rearrangements. Clonal rearrangements were identified by semiquantitative polymerase chain reaction amplification and sequencing of TCR-beta chain genes in nine patients and TCR-gamma chain genes in two patients. A single dominant clone was detected in multiple separate LyP lesions, often of different histologies, in nine patients. The same clone was detected in LyP lesions and the anaplastic large cell lymphoma (ALCL) of 2 patients and the mycosis fungoides (MF) of 2 other patients. No dominant clone could be detected in one patient with LyP uncomplicated by lymphoma or in a second patient with LyP and MF. A T-cell lineage was evident for RS-like cells in cell culture and in type A lesions. These results show that multiple regressing skin lesions and associated T cell lymphomas (MF and ALCL) are clonally related in most LyP patients, which suggest that the disease in these patients was initiated by a non-random genetic event.

Lymphomatoid papulosis in children

BACKGROUND

Although lymphomatoid papulosis is well described in adults, the clinical course, prognosis, risk for lymphoma, and recommendations for follow-up have not been established in children.

OBJECTIVE

Our aim was to analyze our data on six children with lymphomatoid papulosis and to analyze available information on reported cases from the literature to characterize better lymphomatoid papulosis in childhood and to compare it with adult-onset lymphomatoid papulosis.

METHODS

Clinical records, laboratory studies, and histopathologic evaluation of skin biopsy specimens from six children with lymphomatoid papulosis were reviewed. A literature search was also performed and disclosed detailed information on 17 childhood cases.

RESULTS

In most cases childhood lymphomatoid papulosis is clinically and histologically similar to lymphomatoid papulosis in adults, but three unusual patterns were identified in our children: first, after initial outbreak, dwindling outbreaks (both in frequency and number of lesions) until the eruption ceased completely; second, lymphomatoid papulosis localized to one area for years before generalizing, and third, presentation of lymphomatoid papulosis with hundreds of lesions. In our children and in those previously reported, response to systemic antibiotics and potent topical steroids was variable, as in adults. All our children to date have remained healthy; the longest period of follow-up is 9 years. However, in previously reported cases two patients with childhood-onset lymphomatoid papulosis had lymphoma as adults.

CONCLUSION

Childhood lymphomatoid papulosis may be more likely to resolve spontaneously than adult lymphomatoid papulosis; nevertheless these children may still be at risk for lymphoma and thus need lifelong follow-up.

Lymphomatoid papulosis associated with Ki-1-positive anaplastic large cell lymphoma. A report of two cases and a review of the literature

BACKGROUND

Lymphomatoid papulosis (LyP) is an uncommon disorder characterized by recurrent papulonodular cutaneous lesions that last from 4 to 5 weeks and often heal with hypopigmented or hyperpigmented scarring. Prognosis is varied, 10%-20% of patients have associated lymphomas: mycosis fungoides, T-cell immunoblastic lymphoma, or Hodgkin's disease, which can precede, occur simultaneously with, or follow the diagnosis of LyP. Anaplastic large cell lymphoma (ALCL) is histologically and phenotypically similar to LyP and also appears as part of this disease spectrum. Recent reports analyzing immunophenotype and T-cell receptor gene rearrangements in patients with both LyP and lymphoma suggest that they are derived from an identical T-cell clone, in the rare cases studied.

METHODS

The case histories of two patients with LyP in whom ALCL involving the skin and lymph nodes subsequently developed are presented.

RESULTS

Intensive treatment with combination chemotherapy resulted in complete remission of ALCL in both patients, followed by the recurrence of LyP. A spontaneous remission of LyP occurred in the initial patient described, whereas the second patient suffered recurrences of both LyP and ALCL despite therapy.

CONCLUSIONS

The case histories presented illustrate the immunophenotypic and morphologic similarities of ALCL and LyP, and the difficulties in distinguishing between them. Both entities can occur in a single patient, as shown by this report, supporting a close relationship between these processes. However, different clinical behavior and response to therapy are apparent, which connote a fundamental difference in the biologies of these neoplastic disorders. A review of the literature concerning the association between these entities is provided.

Lymphomatoid papulosis associated with acquired ichthyosis

We describe a 64-year-old man with lymphomatoid papulosis associated with acquired ichthyosis. The papulonodular lesions were composed of large atypical lymphocytes positive for CD3, CD4, and Ki-1. The ichthyosiform eruption also occurred on the extremities and had the histologic features of ichthyosis vulgaris. Although monoclonality of infiltrating cells could not be demonstrated, acquired ichthyosis appears to be induced in patients with lymphomatoid papulosis by the same pathomechanism underlying other lymphoproliferative diseases.

Lymphomatoid papulosis

Lymphomatoid papulosis is a chronic disease of cutaneous lymphoid infiltration characterized clinically by involuting and recurring papules, plaques, and nodules. The intriguing combination of a usually benign clinical course, a cytologically malignant lymphoid infiltrate on histologic examination, and a clear, but sporadic association with extracutaneous lymphomas has stimulated significant investigation. Application of recent technical advances to research in lymphomatoid papulosis prompts this review.

T-cell receptor gene rearrangement studies as a diagnostic tool in lymphoproliferative skin diseases

The growth of our knowledge in T-cell biology, in particular the molecular biology of the T-cell receptor (TCR), has provided a means to molecularly characterize lymphoproliferative diseases of the skin based on the presence or absence of a clonal population of T lymphocytes. TCR gene rearrangement studies, by Southern blot analysis, have aided the investigative dermatologist in gaining insights into the pathogenesis and clonal evolution of lymphoproliferative skin diseases. In addition, the application of TCR gene rearrangement studies as a diagnostic aid in the evaluation of lymphoproliferative skin diseases has been introduced into clinical dermatology. Despite its enormous research value, TCR gene rearrangement studies presently have limited applications as an independent diagnostic tool. However, as our knowledge and experience grows and as the application of new techniques provides us with greater detection sensitivity and specificity, the diagnostic utility of TCR gene rearrangement studies will be enhanced.

Diagnostic difficulties in 'non-mycotic' cutaneous lymphoproliferative diseases

The diagnosis of cutaneous lymphoproliferative diseases is an area of bewildering complexity to many histopathologists. This article concentrates on 'non-mycotic' cutaneous diseases. The 'current state of the diagnostic art' is critically assessed. Cutaneous 'pseudolymphoma' is relegated to the position of an aid-memoire and is not a diagnosis. Inadequacies in the classification of cutaneous lymphoma are discussed and the non-specificity of many histopathological features is highlighted. The status of specific entities is analysed and the contribution of modern investigative techniques in diagnosis is evaluated. This includes cutaneous T-cell lymphomas with a detailed consideration of large cell lymphoma heterogeneity. Cutaneous B-cell diseases are shown to be an unresolved diagnostic maze and the necessity for new clearly defined diagnostic criteria is emphasized. Evidence is presented to show that many cutaneous lymphoproliferative diseases lie on continuous spectra that, initially, are probably antigenically driven, and that a diagnosis is best achieved by a multifaceted approach. This is exemplified by cutaneous diseases that have origins from both B- (cutaneous lymphoid hyperplasia/lymphoma) and T-cells (lymphomatoid papulosis, lymphomatoid granulomatosis and mycosis fungoides). The future diagnostic role of the polymerase chain reaction and cytogenetic analysis is discussed. Intriguingly, recent molecular evidence has shown that lymphomatoid papulosis, cutaneous T-cell lymphoma, CD30 positive large cell lymphoma and Hodgkin's disease can originate from a single T-cell clone and display an identical chromosomal translocation and T-cell receptor rearrangement. Careful clinico-pathological correlation combined with prolonged patient follow-up remains the gold standard for diagnosis.

Hodgkin's disease, lymphomatoid papulosis, and cutaneous T-cell lymphoma derived from a common T-cell clone

BACKGROUND

Lymphomatoid papulosis is a benign cutaneous eruption that in 10 to 20 percent of patients is associated with the development of lymphoma. The atypical cells of lymphomatoid papulosis histologically resemble the malignant cells of cutaneous T-cell lymphoma or the Reed-Sternberg cells of Hodgkin's disease. We studied a patient in whom lymphomatoid papulosis developed in 1971, Hodgkin's disease in 1975, and cutaneous T-cell lymphoma in 1985, to determine whether these diseases are clonally related.

METHODS

The T-cell-receptor alpha-chain gene was cloned and sequenced from a cell line derived from the advanced-stage cutaneous T-cell lymphoma, and the polymerase chain reaction was used to search for this rearrangement of the alpha-chain gene in tissues obtained earlier that were affected by Hodgkin's disease or lymphomatoid papulosis.

RESULTS

The tumor-specific rearrangement of the alpha-chain gene was detected in the patient's earlier tissues affected by lymphomatoid papulosis and Hodgkin's disease, but not in control tissue, including uninvolved tissues from the staging laparotomy for Hodgkin's disease. Cytogenetic studies revealed a translocation, t(8;9)(p22;p24), in cutaneous T-cell lymphoma lines and in a dermatopathic lymph node removed two years before the clinical onset of the cutaneous T-cell lymphoma. Immunohistochemical findings were consistent with an activated T-cell phenotype for the atypical cells of lymphomatoid papulosis, the Reed-Sternberg cells of Hodgkin's disease, and the malignant cells of the T-cell lymphoma.

CONCLUSIONS

Lymphomatoid papulosis, Hodgkin's disease, and cutaneous T-cell lymphoma can be derived from a single T-cell clone. A t(8;9) genetic translocation may be involved in the pathogenesis of lymphomatoid papulosis or its progression to malignant disease.