Diagnostic and management challenges in primary cutaneous anaplastic large cell lymphoma with necrosis,inflammation,and surgical intervention:A case report

BACKGROUND Primary cutaneous anaplastic large cell lymphoma(PC-ALCL)poses significant diagnostic difficulties due to its similarity in the appearance of skin lesions with chronic inflammatory disorders and other dermatological conditions.This study aims to investigate these challenges by conducting a comprehensive analysis of a case presenting with PC-ALCL,emphasizing the necessity of accurate differentiation for appropriate management.CASE SUMMARY An 89-year-old female patient with diabetes and hypertension presented with arm and abdominal ulcerated mass lesions.Diagnostic procedures included skin biopsies,histopathological assessments,and immunohistochemistry,complemented by advanced imaging techniques to confirm the diagnosis.The patient’s lesions were determined as PC-ALCL,characterized by necrosis,chronic inflammation,and a distinct immunophenotypic profile,including CD30,CD3,CD4,and EBER,CD56,MUM-1,Ki 67-positive in>80%of tumor cells,CD10,but negative for anaplastic lymphoma kinase,CD5,CD20,PAX-5,Bcl-2,Bcl-6,CD8,and CD15.Recurrence was not reported at the 6-month follow-up.CONCLUSION Accurate PC-ALCL differentiation from similar conditions is crucial for effective management and requires a multidisciplinary approach.

Primary cutaneous anaplastic large cell lymphoma with overexpressed Ki-67 transitioning into systemic anaplastic large cell lymphoma:A case report

BACKGROUND Primary cutaneous anaplastic large cell lymphoma(PC-ALCL)differs from systemic anaplastic large cell lymphoma(sALCL)in cell biological behavior,clinical features,treatment,and outcome.PC-ALCL has been reported to rarely transition into sALCL,but the underlying mechanism is not clear.Here we report such a case with certain characteristics that shed light on this.CASE SUMMARY Herein,we report a 43-year-old male with symptoms of a skin nodule and histologically confirmed PC-ALCL with high expression of Ki-67.After three months of observation,two skin nodules re-appeared with muscle layer involvement and was histologically confirmed as sALCL.Seventeen months after receiving six cycles of CHOP regimen,the patient had pain in the chest and back,cough,shortness of breath,and night sweats.This was confirmed as relapse of sALCL by immunohistochemistry and several organs,such as the lung were involved as shown by positron emission tomography/computed tomography.After four cycles of DICE plus chidamide regimens followed by auto-hematopoietic stem cell transplantation(ASCT),complete remission(CR)duration was achieved for twelve months while the patient was on maintenance with chidamide(20 mg)pills.CONCLUSION This case had significantly high expression of Ki-67 when diagnosed as PC-ALCL initially and then transitioned into sALCL,which is rare.Auto-ASCT combined with demethylation drugs effectively maintained CR and prolonged progression free survival.

Transcriptome sequencing analysis of ursolic acid-mediated proliferation suppression on cutaneous T-cell lymphoma cells

Background:Ursolic acid is a triterpenoid compound found in natural plants that exhibits antiproliferative effects in various cancer cells.Our study is the first to demonstrate the strong inhibitory effects of ursolic acid on the proliferation of cutaneous T-cell lymphoma(CTCL)cells.We aimed to further investigate the underlying mechanism of the proliferation inhibition induced by ursolic acid in CTCL cells using transcriptome sequencing.Methods:Cell counting kit-8 assays were used to observe the effects of six traditional medicine monomers on the proliferation of CTCL cells.Transcriptome sequencing was used to identify differentially expressed genes after ursolic acid treatment.Bioinformatics analysis was performed to determine the potential mechanism.Real-time quantitative PCR and western blotting analyses were performed to confirm the sequencing results and verify the possible mechanisms of ursolic acid-mediated proliferation inhibition in CTCL cells.Results:Ursolic acid exhibited the strongest inhibitory effect on the proliferation of CTCL cells among the six traditional medicine monomers.Transcriptome sequencing analysis showed that 2,466 genes were significantly altered.Combined with Kyoto Encyclopedia of Genes and Genomes functional enrichment analysis and protein-protein interaction network analysis,the interaction of various pathways and signaling molecules,such as tumor necrosis factor-α,NLR family pyrin domain containing 1,c-Jun N-terminal kinase,and melanoma differentiation-associated gene 5,accounted for the anti-tumor effects of ursolic acid in CTCL cells.Conclusion:Ursolic acid significantly inhibited the proliferation of CTCL cells,and our study laid a theoretical foundation for the future treatment of CTCL using ursolic acid.

Marginal zone lymphoma with severe rashes: A case report

BACKGROUND Marginal zone lymphoma(MZL)is an indolent subtype of non-Hodgkin lymphoma(NHL),which is rare clinically with severe rashes as the initial symptom.CASE SUMMARY This study reports a case of MZL with generalized skin rashes accompanied by pruritus and purulent discharge.First-line treatment with rituximab combined with zanubrutinib had poor effects.However,after switching to obinutuzumab combined with zanubrutinib,the case was alleviated,and the rashes disappeared.CONCLUSION For patients with advanced stage MZL not benefiting from type I anti-CD20 monoclonal antibody(mAb)combination therapy,switching to a type II anti-CD20 mAb combination regimen may be considered.This approach may provide a new perspective in the treatment of MZL.

Relative frequency and survival of primary cutaneous lymphomas： a retrospective analysis of 98 patients

Background The World Health Organization and European Organization for Research and Treatment of Cancer （WHOEORTC） classification in 2005 promoted the comparisons of primary cutaneous lymphoma （PCL） subtypes between different countries.The relative frequency of PCL varied according to geography.The study aimed to analyze the relative frequency and survival of PCLs in China and to compare the data with the published results from other countries.Methods We analyzed 98 patients with PCLs over a 6-year period and reclassified them according to the most recent WHO-EORTC classification （2005）.Disease-specific survival rate and curves according to specific subtypes such as mycosis fungoides,lymphomatoid papulosis,and primary cutaneous peripheral T-cell lymphoma,unspecified was also calculated.Results The relative rate of PCL in China was distinct from those in Western countries.Our study showed a higher frequency of cutaneous T-and NK-cell lymphomas （CTCLs） （94%）,and a lower frequency of cutaneous B-cell lymphomas （CBCLs） （6%）.The 5-year survival rate of the total PCLs was 82%.There was no significant difference in the 5-year survival rate （P 〉0.05 by Log-rank test） between CTCL （80%） and CBCL （100%）.Conclusions The higher percentage of CTCL in China may provide a clue to further study the etiological factors of PCLs.Racial variations in factors such as HLA determinants may play a role in the development of CTCL.

The Clinical Pathologic Analysis of Radiotherapy for Cutaneous B-cell Lymphoma

OBJECTIVE To report results of radiation therapy treatment of 30 B-cell lymphoma patients with an initial cutaneous presentation according to the new classification by the WHO/EORTC. METHODS Thirty patients with cutaneous B-cell lymphoma （CBCL） were treated by cutaneous irradiation based on the number and location of the lesions and the stage of their tumor. Treatment was conducted using a Satume Clinac. RESULTS A complete response （CR） from the treatment for our series was 86%. The length of complete remission ranged from 4 to 301 months. Three patients （11%） developed a partial response （PR）. One patient was progressive. Disease-free survival（DFS） at 10 years was 87%. Three patiens died [One PCMZL two PCLBCL leg type （29%）]. Radiotherapy was generally well tolerated. CONCLUSION According to the WHO/EORTC classification, the survivor results were good for PCMZL and PCFCL. The PCLBCL leg type had a poor prognosis. Localized field irradiation is an effective treatment for some localized forms of primary cutaneous B-cell lymphoma, and this mode of therapy can produce prolonged remissions.The patients with wide-spread skin involvement are usually candidates for extended field irradiation and/or chemotherapy. For advanced stages of cutaneous B-cell lymphoma, where chemotherapy is the treatment of choice, a degree of palliation can be achieved using local field irradation.

Palliative Local Radiotherapy in the Treatment of Tumor-stage Cutaneous T-cell Lymphoma/ Mycosis Fungoides

Objective To determine the efficacy of palliative radiotherapy in treating tumor-stage cutaneous T-cell lymphoma/mycosis fungoides(MF).Methods From January 2008 to January 2013,a total of 11 patients with tumor-stage MF were treated with local radiation therapy in Peking Union Medical College Hospital.The median age of these patients was 53.36±14.45 years.Female-male ratio was 1:1.2.The average course of disease was 10.82±3.37 years.All the patients were treated with local electronic beam irradiation with a total median dosage of 48.55±9.51(40-74) Gy in an average of 24.55±5.57(20-40) fractions,5 fractions per week.Results The median follow-up time was 55.27±29.3(13-103) months.No severe acute or chronic side effects of irradiation were observed.Complete clinical response(CR) rate of the radiated sites was 54.5%(6/11),partial response(PR) rate was 36.4%(4/11),and the overall response rate(CR+PR) was 90.9%.One patient showed no response.Conclusion Local radiotherapy with psolaren plus ultraviolet A and/or interferon maintaining treatment is an effective palliative therapy in the treatment of tumor-stage MF patients.

Epigenetics of cutaneous T-cell lymphoma:biomarkers and therapeutic potentials

Cutaneous T-cell lymphomas(CTCLs)are a heterogeneous group of skin-homing non-Hodgkin lymphomas.There are limited options for effective treatment of patients with advanced-stage CTCL,leading to a poor survival rate.Epigenetics plays a pivotal role in regulating gene expression without altering the DNA sequence.Epigenetic alterations are involved in virtually all key cancerassociated pathways and are fundamental to the genesis of cancer.In recent years,the epigenetic hallmarks of CTCL have been gradually elucidated and their potential values in the diagnosis,prognosis,and therapeutic intervention have been clarified.In this review,we summarize the current knowledge of the best-studied epigenetic modifications in CTCL,including DNA methylation,histone modifications,micro RNAs,and chromatin remodelers.These epigenetic regulators are essential in the development of CTCL and provide new insights into the clinical treatments of this refractory disease.

T-CELL RECEPTOR GENE REARRANGEMENT ANALYSIS IN THE PRIMARY CUTANEOUS T-CELL LYMPHOMA

Object: The present paper is to evaluate the significance of T cell receptor (TCR) gene rearrange ments in primary cutaneous T cell lymphomas (PCTCL) as detected by analysis of Southern Blot (SBA) and polymerase chain reaction (PCR). Patients and Methods: Skin specimens and peripheral blood samples were taken from 44 patients with PCTCL, including 30 patients with mycosis fungoides (MF), 2 patients with Sezary's syndrome (SS), and 12 patients with PCTCL other than MF and SS (PNCTCL). 11 patients with a presumptive diagnosis of MF, 23 patients with lymphoproliferative dermatoses including lymphomatoid papulosis (LyP) and 8 patients with benign cutaneous lymphoid infiltrates were simultaneously studied by the amplification of junctional V (variable) J (joining) sequences of the rearranged TCRγ genes by PCR(TCRγPCR) and the analysis of TCRb chain genes by SBA(TCRβSBA) for detection of clonal gene rearrangements (GR). One lymph node specimen of a case with MF IIA was also detected by TCRγ PCR and TCRβSBA. Results: In MF, GR were detected by TCRγPCR and TCRβSBAb in 83.3 85.7% and 66.7% 71.4% of skin specimens of cases IIA IIB and in 57.1% 70.0% and 14.3% 10.0% of those of cases IA IB, respectively. GR were seen in 66.7% 71.4% and 33.3% 43.0.% of blood samples of cases IIA IIB, and 42.9% 40.0% and 0 10.0% of those of cases IA IB, respectively. GR was confirmed by TCRγ PCR and TCRβSBA in one lymph node showing dermato pathic lymphadenopathy of a case with MF IIA. In 11 patients of clinically suspected MF, GR were present in skin specimens of 5 cases (45.4%) and in blood samples of 3 cases ( 27.3% ) by TCRγ PCR. In PNCTCL, GR were found in 9 skin specimens (90.0%) from 10 patients detected by TCRγ PCR and in 6 skin specimens (75.0%) from 8 patients detected by TCRβSBA. GR were also seen in 6 blood samples (72.8%) from 11 patients detected by TCRγ PCR, and in 7 blood samples (70.0%) from 10 patients by TCRβSBA. In SS and LyP, GR were detected by TCRγ PCR and TCRβSBA in each of the two skin specimens of two cases with LyP and in each of the two blood samples of two cases with SS. GR were seen in one skin specimen of one case with SS and one blood sample of one case with LyP detected by TCRγPCR. Conclusions: This study demonstrated that TCRγ PCR is a rapid, more sensitive tool than TCRβSBA, can be used in the analysis of T cell clonality in skin, lymph node and blood samples of patients with PCTCL and indicated that this method forms a useful supplement to other methods for diagnosis of early and suspected MF, confirmation of PNCTCL and determination of extracutaneous involvement of lymph node and blood.

NUCLEOLAR ORGANIZER REGIONS IN CUTANEOUS T CELL LYMPHOMAS

The present work studied the application of AgNOR count to differential diagnosis between cutaneous T cell lymphoma (CTCL) and cutaneous pseudolymphoma (CPL). Paraffin sections from 50 mycosis fungoides (22 MFI-Premycotic stage, 24 MF Ⅰ infiltrative stage and 4 MF Ⅲ - tumor stage), 2 nonepidermotropic cutaneous T cell lymphoma (NECTCL) and 9 CPL were investigated. In each case, 200 cells randomly selected were examined using a × 100 oil immersion lens. The mean number, standard deviation and standard error of the mean of AgNOR counts were as follows: MFⅠ 1.17±0.09, SEM = 0.01; MⅡ 1.17±0.01, SEM = 0.01; MF Ⅲ. 3.55±0.87, SEM = 0.43; NECTCL 4.5±0.28, SEM -0.199; CPL 1.17±0.1, SEM ± 0.03. The results revealed a highly significant difference between CTCL (MFⅢ+NECTCL) and CPL (t = 4.75, P<0.001), tumor stage (MF Ⅲ) and pretumor stage (MFI, MF Ⅱ) of mycosis fungoides (t = 4.75, P<0.001). Thus. AgNOR count is valuable in differential diagnosis.

IMMUNOPHENOTYPING OF CUTANEOUS GERMINAL CENTER CELL-DERIVED LYMPHOMAS

Monoclonal antibodies were used to label cutaneous germinal center cell-derived lymphomas <CGCCL) obtained from 10 patients. According to the Kiel classification, they were classified into 2 types. Eight patients had centroblastic/centrocytic <CB/CC) lymphomas while 2 patients and centrocytic (CC) lymphomas. After monoclonal antibody labelling, the results were consistent with those of the clinical and morphologic analyses. Of the 10 cases, 9 were B1 positive, 6 were K positive, and 4 were λ positive. In 8 cases labeled with immunoglobulin, 6 were IgGFab positive, 2 were IgM positive and 8 were IgA negative. Five cases (CB/CC 3, CC 2) were both Bl, K and IgG positive (γ K). Four cases CB/CC were both Bl and A positive. Only one case (CB/CC) was both K and IgM positive (μ K). Two cases (CB CC) were both A and IgG positive (γ λ). The results indicate that Bl, K and A are the most important markers to phenotype cutaneous B-cell lymphomas. Our findings also show a higher percentage of y K types in CGCCL as compared with Western countries.

Natural killer reprogramming in cutaneous T-cell lymphomas: Facts and hypotheses

To better understand the pathogenesis of Sézary cells, distinguish them from reactive skin-infltrating T-cells and improve disease treatment, efforts have been made to identify molecular targets deregulated by the malignant process. From immunophenotypic analysis and subtractive differential expression experiments to pan-genomic studies, many approaches have been used to identify markers of the disease. During the last decade several natural killer （NK） cell markers have been found aberrantly expressed at the surface of Sézary cells. In particular, KIR3DL2/CD158k, expressed by less than 2% of healthy individuals CD4＋ T-cells, is an excellent marker to identify and follow the tumor burden in the blood of Sézary syndrome patients. It may also represent a valuable target for specifc im-munotherapy. Other products of the NK cluster on chromosome 19q13 have been detected on Sézary cells, raising the hypothesis of an NK reprogramming process associated with the malignant transformation that may induce survival functions.

Chidamide combined with traditional chemotherapy for primary cutaneous aggressive epidermotropic CD8+cytotoxic T-cell lymphoma:A case report

BACKGROUND Traditional chemotherapy has benefited many patients with non-Hodgkin's lymphoma,but results in a very poor response in patients with rare lymphomas or refractory lymphomas.Previous studies have shown that chidamide has potential anti-lymphoma activity and reverses lymphoma cell chemoresistance to increase the chemosensitivity of lymphoma cells to traditional chemotherapy.CASE SUMMARY A 14-year-old boy was admitted to our hospital with a 5-d history of generalized erythema,papules,and blisters.Initially,the disease was refractory to potent antiallergic and anti-infective treatment,and his condition progressively worsened.Skin biopsy revealed primary cutaneous aggressive epidermotropic CD8+cytotoxic T-cell lymphoma.Considering that the disease is extremely rare in clinical practice,existing case reports have shown poor efficacy with traditional chemotherapy alone.We recommend chidamide combined with traditional chemotherapy for treatment.The regimen was as follows:Chidamide 30 mg/biw,cyclophosphamide 1100 mg/d1,pirarubicin 70 mg/d1,vincristine 2 mg/d1,dexamethasone 20 mg/d1-5,etoposide 100 mg/d1-5,in a 21 d cycle.The treatment effect was considerable,and complete remission was achieved after 4 cycles of treatment,after which the patient completed a total of 6 cycles of treatment.Subsequently,the patient regularly took chidamide 20 mg/biw as maintenance therapy for 1 year.To date,the patient has been disease-free for 3 years.CONCLUSION This case suggests that the combination of chidamide and traditional chemotherapy is effective in primary cutaneous aggressive epidermotropic CD8+cytotoxic T-cell lymphoma.

Clinicopathology, immunophenotype, T cell receptor gene rearrangement, Epstein-Barr virus status andp53 gene mutation of cutaneous extranodal NK/T-cell lymphoma, nasal-type

Background Extranodal natural killer/T-cell （NK/T cell） lymphoma, nasal-type, is a rare lymphoma. Skin is the second most common site of involvement after the nasal cavity/nasalpharynx. The aim of this study was to investigate the clinicopathologic features, immunophenotype, T cell receptor （TCR） gene rearrangement, the association with Epstein-Barr virus （EBV） infection and p53 gene mutations of the lymphoma. Methods The clinicopathologic analysis, immunohistochemistry, in situ hybridization for EBERI/2, TCR gene rearrangement by polymerase chain reaction （PCR）, mutations of p53 gene analyzed by PCR and sequence analysis were employed in this study. Results In the 19 cases, the tumor primarily involved the dermis and subcutaneous layer. Immunohistochemical staining showed that most of the cases expressed CD45RO, CD56, CD3E, TIA-1 and GrB. Three cases were positive for CD3 and two cases were positive for CD30. Monoclonal TCRy gene rearrangement was found in 7 of 18 cases. The positive rate of EBERI/2 was 100%. No p53 gene mutation was detected on the exon 4-9 in the 18 cases. Fifteen cases showed Pro （proline）/Arg （arginine） single nucleotide polymorphisms （SNPs） on the exon 4 at codon 72. The expression of p53 protein was 72% （13/18）immunohistochemically. Conclusions Cutaneous NK/T-cell lymphoma is a rare but highly aggressive lymphoma with poor prognosis. No p53 gene mutation was detected on the exon 4-9, and Pro/Arg SNPs on p53 codon 72 were detected in the cutaneous NK/T-cell lymphoma. The overexpression of p53 protein may not be the result of p53 gene mutation.

Ultrasound-guided microwave ablation as a palliative treatment for mycosis fungoides eyelid involvement:A case report

BACKGROUND Mycosis fungoides(MF)is a form of lymphoma derived from heterogeneous T cells,and eyelid involvement is extremely rare.The common methods to treat eyelid involvement are radiotherapy and chemotherapy,but their efficacies are limited.Herein,we report a case of advanced-stage MF eyelid involvement,propose ultrasound(US)-guided microwave ablation(MWA)therapy and present a literature review.CASE SUMMARY A male patient was admitted to our hospital in June 2018 and diagnosed with MF via radiological and histopathological examinations.The patient’s condition was not well controlled by various conventional chemotherapies.US-guided MWA was performed to relieve the patient’s symptoms and improve his quality of life,showing satisfactory efficacy.CONCLUSION Eyelid involvement is one of the most troublesome clinical problems for advanced-stage MF patients.This is the first report on the use of US-guided MWA as a palliative therapy for MF eyelid involvement;the treatment successfully relieved the patient’s clinical symptoms and reduced his anxiety behaviours.Our study sheds new light on methods for improving the clinical management of eyelid involvement in MF.

Sezary syndrome： a rare form of cutaneous T-cell lymphoma

Sezary syndrome （SS） is an erythrodermic, aggressive, cutaneous T-cell lymphoma （CTCL） characterized by a malignant T-cell clone that localizes in the blood and skin, and its diagnosis is based on clinical, histological and biological features. Here we describe a typical case of SS.

EXPRESSION OF PROLIFERATING CELL NUCLEAR ANTIGEN IN CUTANEOUS MALIGNANT LYMPHOMAS AND LYMPHOID INFILTRATES

Paraffin-embedded tissue of skin biopsy specimens taken retrospectively from 24 patients with cutaneous malignant lymphomas (CML) and 8 patients with cutaneous lymphoid infiltrates (CLI) and other dennatoses were studied retrospectively with PCIO immunostaining. The results show a statistical significant difference among PCIO indices for cutaneous genuine histiocytic lymphoma (CGHL), cutaneous germinal center cell-derived lymphomas (CGCCL), cutaneous peripheral T-cell lymphomas (CPTL), non-mycosis fungoides (MF) and Sezary's syndrome (SS), and MF when compared with those for CLI. There is a linear relationship between PCIO index and square root of PCIO density, both of which seem to have a parallel relationship to the severity of malignancy in CML. The nuclear volume of the positive tumor cell or lymphocyte with PCIO immunostaining may be also useful in differentiating CML from CLI.

Aberrant expression of CD56 by circulating Sézary syndrome malignant T lymphocytes

Sézary syndrome(SS) is an aggressive variant of cutaneous T cell lymphoma characterized by the presence of malignant T cells in the skin, peripheral blood and lymph nodes. The tumoral population typically displays a CD3+ CD4+ CD45RO+ memory T cell phenotype. We report a case of SS with an aberrant CD56+ immunophenotype. This patient presented with a generalized erythroderma and palpable small axillary lymph nodes.SS(stage IVA) was diagnosed on histological criteria and by the detection of a major T cell clone in skin and blood, an elevated CD4/CD8 T cell ratio and Sézary cells count > 1000/mm3. Beside the Sézary cell marker KIR3DL2, immunostainings revealed that two third of the malignant cells expressed CD56 but no other natural killer(NK) cell marker such as CD16, CD160 or NKp46. This atypical expression was not linked to an activation-dependent process and remained stable during the time course of the disease. No loss of the panT-cell markers CD2, CD3 or CD4 was detected while a complete down-modulation of CD26 was observed. Despite several lines of treatment, no durable amelioration was observed and patient died after 10 mo of follow-up. Because this CD4+ CD56+ SS case is the only one reported so far, the functional significance of CD56 expression remained difficult to assess in terms of aggressiveness and prognosis.

Overview of genetic signaling pathway interactions within cutaneous malignancies

Melanoma and non-melanoma cutaneous malignancies are some of the leading causes of cancer-related death in the United States.Though melanoma is more known to have a high mortality rate,the total mortality per year is nearly equal for between melanoma and non-melanoma skin cancer.Moreover,the non-melanoma types of cutaneous malignancies have potential to become locally invasive and even metastasize with very little to no treatment options when advanced.The development of these malignancies involves various genetic pathways through the four hallmarks of cancer development:malignant cell growth,apoptosis evasion,the use of supporting stroma and vascularization,and modulating and promoting an inadequate immune response.The genetic signaling pathways of basal cell carcinoma,squamous cell carcinoma,verrucous carcinoma,basosquamous cell carcinoma,melanoma,and cutaneous T-cell lymphoma interact with each other through genetic predisposition as well as with environmental exposures.Furthermore,solar ultraviolet radiation and chronic inflammatory states are found to initiate the progression of many of these cutaneous malignancies.This paper includes validated models of genetic pathways,emerging pathways,and crosstalk between genetic pathways through the four hallmarks of cancer development.Moreover,unlike most reviews addressing oncogenetics of the well-recognized,as well as newly discovered,genetic pathway mutations,this review stresses that these pathways are not fixed but rather exist in dynamic,interrelated,interactive,complex,and adaptive flux states.

Clinicopathologic,immunophenotypic and ultrastructrual analyses of ATLL patients with cutaneous involvement

Objective To study 4 cases of adult T cell leukemia/lymphoma (ATLL) as sociated with cutaneous lesions for clinicopathology, immunophenotype, human T cell leukemia/lymphoma virus type Ⅰ (HTLV Ⅰ) provirus DNA and their ultrastru cture. At the same time, HTLV Ⅰ provirus DNA of ATLL patients were also compar ed with 18 cases of cutaneous lymphoma (CL), two cases of actinic reticuloid as well as two cases of lymphocytic infiltration.Methods Immunohistochemistry studies were carried out on the infiltrati ng cells using monoclonal antibodies against CD45 RO, CD20, CD68 on paraffin e mbedded sections by ABC method and using monoclonal antibodies against CD3, CD4 and CD8 with indirect immunofluorescence (IIF) on frozen sections. Skin biopsies were examined by electron microscope. Serum and bone marrow cells were tested f or antibodies against HTLV Ⅰ associated antigen by IIF, and HTLV Ⅰ provirus DNA was examined by PCR method.Results The research showed four patients with ATLL manifesting cutaneo u s lesions, were subsequently found with additional systemic symptoms, as extensi vely enlarged superficial lymph node, abnormal increased IL 2 receptor, flower like cells in their peripheral blood and marrow. The HTLV Ⅰ provirus DNA was positi ve in the peripheral blood, bone marrow, cutaneous lesions and lymph node biopsy specimens by using PCR amplification of specific HTLV Ⅰ fragment while 18 cas es of the CL were negative for HTLV Ⅰ. The special ultrastructure of skin lesi ons was also found in ATLL patients.Conclusions The cutaneous involvement in ATLL is a type of cutaneous T cell lymphoma (CTCL) but shows some differential immunological markers for diffe rential diagnosis. The examination of HTLV Ⅰ antibodies or HTLV Ⅰ provirus D NA is necessary for diagnosis of ATLL. The ultrastrustural characteristics in skin lesions of ATLL were of atypic al lymphocytes and mononuclear cells invading the epidermis, and the mononuclear cells are possessing the phagocytic function and phagocytizing the degenerated epidermic cells or lymphocytes.