Systemic inflammation and its relationship with pruritus in early-stage mycosis fungoides.

The underlying mechanisms mycosis fungoides (MF)-related pruritus remain unclear, and the link between pruritus and systemic inflammation in MF is unexplored. We aimed to investigate systemic inflammation in MF patients and its potential connection to pruritus. In this retrospective study, demographic characteristics, MF stage, clinical and laboratory findings, and neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), monocyte-lymphocyte ratio (MLR), systemic immune-inflammation index (SII), systemic inflammation response index (SIRI) and pan-immune inflammation value (PIV) were assessed for all participants. Additionally, mSWAT scores, Dermatology Life Quality Index (DLQI), and pruritus presence and intensity via Visual Analogue Scale (VAS) scoring were recorded for MF patients. A total of 81 patients with early-stage MF and 50 controls were enrolled. Itching was present in 41 patients (50.6%). NLR, PLR, SII, SIRI and CRP values in the MF group were significantly higher. CRP, NLR, mSWAT and DLQI score were significantly higher in MF patients with pruritus than those without. Pruritus was positively correlated with DLQI, mSWAT, CRP, NLR, MLR and SIRI. VAS score was positively correlated with eosinophil count and DLQI. In the multivariate logistic regression model, only NLR was an independent and significant associate of pruritus in patients with MF. This study provides evidence of enhanced systemic inflammation in early-stage MF patients. Additionally, the correlation between pruritus with mSWAT scores and systemic inflammation parameters suggests a potential link between pruritus and the inflammatory milieu in MF.

Utility of Low-Dose Duvelisib for Advanced Mycosis Fungoides: A Single-Institution Study.

Duvelisib, a small-molecule phosphatidylinositol 3-kinase-δ,γ inhibitor, has shown efficacy for mycosis fungoides (MF) at dosage ranges of 25-100 mg twice daily (BID), but with significant toxicity. We conducted a retrospective cohort study of patients with advanced MF treated with low-dose duvelisib (15 mg every other day to BID), in an effort to minimize toxicity. A total of 7 patients were included. The overall response rate on duvelisib was 71%, with the remaining patients maintaining stable disease. Mean modified Severity Weighted Assessment Tool score improved by 57.4% and mean percent body surface area involved improved by 52%. Median progression-free survival was 10.3 months. Adverse events occurred in 4 of 7 patients, the most common being fatigue (2/7; grades 1-2), nausea (2/7; grades 1-2), and transaminitis (2/7; grade 3). Overall, low-dose duvelisib showed efficacy for advanced MF with less toxicity, providing a rationale for its use as monotherapy and potentially combinatorial therapy.

Morphoea presenting histopathologically as mycosis fungoides: an illustrative series of four cases.

AIMS: There have been exceptional reports of morphoea presenting with epidermal changes overlapping histopathologically with cutaneous T cell lymphoma of the mycosis fungoides type (MF). This phenomenon gives rise to an ambiguous clinicopathological scenario in which distinguishing these conditions may be challenging. The aim of this study is to characterise the clinical, histopathological and molecular findings of this phenomenon through a case series. METHODS AND RESULTS: Four patients with classical clinical presentation of morphoea but unusual histopathology displaying typical findings of morphoea, together with intra-epidermal CD8 positive lymphocytes indistinguishable from MF, were identified. The clinical phenotypes of morphoea were varied, and they all presented early in the active phase of the disease. They all exhibited intra-epidermal lymphocytes with tagging and cytological atypia. Pautrier-like microabscesses were also seen. Using molecular analysis, two cases showed clonal TCR gene rearrangement. Follow-up of all cases has been consistent with classical morphoea. CONCLUSION: Early morphoea can seldom present with atypical clonal intra-epidermal lymphocytes indistinguishable from MF. The fact that these changes can occur in several different clinical subtypes of morphoea raises the possibility that this could be a pattern of inflammation in early disease more common than currently appreciated.

Possible effects of plasminogen activator inhibitor-1 on promoting angiogenesis through matrix metalloproteinase 9 in advanced mycosis fungoides.

Mycosis fungoides (MF) progresses slowly before advancing to skin tumors followed by lymph node and visceral involvement. Among MF progression, stage IIB is an initial time point of tumor formation in MF. Since MF in tumor stage possess abundant blood vessels, it is important to evaluate the pro-angiogenic factors before and after MF in stage IIB. In this report, we investigated pro-angiogenic soluble factors in MF patients, as well as its pro-angiogenetic effects on tumor cells and stroma cells. We first evaluated the serum levels of pro-angiogenic factors in 9 MF patients without tumor formation and 8 MF patients with tumor formation. Among them, the serum MMP-9 and plasminogen activator inhibitors 1 (PAI-1) was significantly increased in MF with tumor formation compared in MF without tumor formation, leading to favorable formation of human dermal microvascular endothelial cells tube networks. Moreover, PAI-1 stimulation significantly increased the mRNA expression and protein production MMP-9 on monocytes derived M2 macrophages and HUT-78. Furthermore, since MMP-9 production from tumor cells as well as stromal cells is suppressed by bexarotene, we evaluate the baseline serum pro-angiogenic factors including MMP-9 in 16 patients with advanced cutaneous T cell lymphoma treated with bexarotene. The serum levels of MMP-2 and MMP-9 was significantly increased in bexarotene non-responded patients compared to responded patients. Our present study suggested the significance of MMP-9 and PAI-1 for the progression of MF stage toward to the tumor stage, and could be a therapeutic target in future.

Generalized early inflammatory morphea mimicking interstitial T-cell lymphoma: A diagnostic pitfall.

Early generalized morphea can clinically mimic mycosis fungoides. The microscopic features of early inflammatory morphea may show variable degrees of infiltration and do not have the characteristic dermal collagen sclerosis. We report the case of a 63-year-old female patient who presented with a 2-month history of an asymptomatic skin rash. Physical examination revealed multiple erythematous to dusky patches on the trunk and thighs, resembling the patch stage of mycosis fungoides. Two skin biopsies were performed, both of which showed prominent interstitial lymphoid infiltration in the reticular dermis without dermal sclerosis. Small lymphocyte exocytosis and lining along the dermal-epidermal junction were observed focally in the epidermis. Small clusters of plasma cells and eosinophils were observed in perivascular areas. Although no predominant clonality was found for CD4 and CD8 stains, 50% loss of CD5 antigen and 90% loss of CD7 antigen expression were apparent in immunohistochemical studies. Subsequent blood tests showed a normal blood cell count and positive human T-lymphotropic virus Type 1 antibodies. The overall findings suggested interstitial mycosis fungoides or early adult T-cell lymphoma-leukemia. The patient refused aggressive treatment, and 3 months later, she presented with indurated plaques from the previous rash. A repeat biopsy revealed the typical features of morphea. This report discussed the pitfalls in the clinical and histopathological diagnosis of early generalized inflammatory morphea that both clinicians and pathologists should consider.

Urticarial mycosis fungoides: A distinctive presentation with blood involvement and a peculiar immunophenotype.

Mycosis fungoides (MF) has been widely reported to mimick a considerable number of different dermatoses, including scarring alopecia, bullous dermatoses or cysts, and comedones. In atypical presentations, histopathology is essential for the diagnosis. We present two cases of MF with clinical urticarial lesions and a striking blood involvement that responded to mogamulizumab treatment. Histopathologically, both cases had classic MF features and shared a peculiar immunophenotype, with positivity for CD25 and FOXP3. Differential diagnoses included urticarial lymphomatoid drug reactions and other lymphomas, like T-cell prolymphocytic leukemia, atypical Sézary syndrome, or adult T-cell lymphocytic leukemia. A low suspicion threshold is necessary for the diagnosis of atypical presentations of MF.

Interstitial mycosis fungoides: A rare presentation of mycosis fungoides with overlapping granulomatous and folliculotropic features.

BACKGROUND: Interstitial mycosis fungoides (IMF) is a rare subtype of mycosis fungoides (MF) characterized by atypical lymphocytes infiltrating the reticular dermis between collagen bundles with limited epidermotropism and variable granulomatous features. METHODS: Retrospective single institution review of 31 cases of IMF including clinical characteristics, disease course and pathological features. RESULTS: Our cohort was predominately male (19; 61%, M:F 1.6:1) with a mean age at diagnosis of 43 years (range 11-85), mean signs/symptoms duration of 7 years prior to diagnosis, and 6 years mean follow-up duration. Clinically, patients often exhibited symmetric ill-defined patches/plaques involving intertriginous regions with tan-yellow hyperpigmentation and follicular-based papules, wrinkling, and alopecia. Lymphadenopathy was noted in seven patients. Fifteen (52%) patients were in near or complete clinical remission at the latest follow-up. T-cell receptor gene rearrangement was positive in 23/24 (96%) cases. Histopathologically, atypical cells were small-medium, CD4+ (29; 94%) or rarely CD4+/CD8+ (1; 3%) lymphocytes infiltrating the reticular dermis with thickened collagen bundles (27; 87%), multinucleated giant cells (12; 39%), and often tracing along adnexa with subtle folliculotropism (12/20; 60%). CONCLUSIONS: Our study demonstrates IMF is an indolent subtype of MF with distinct features, including frequent granulomatous and subtle follicular involvement resulting in alopecia.

Null T-cell phenotype mycosis fungoides with aberrant CD20 and CD56 expression: A diagnostic dilemma.

Mycosis fungoides (MF) represents the most common type of primary cutaneous T-cell lymphoma. Recognition of MF variants with divergent immunophenotypes is important for accurate diagnosis and appropriate management, as they can be confused with other lymphoma subtypes. We present a case of a 49-year-old male previously diagnosed with a cutaneous lymphoproliferative disorder with an unusual NK/T-cell phenotype. He presented with a 10-year history of pelvic girdle rash involving the right hip and upper thigh. The lesions were characterized as atrophic patches concentrated in sun-protected areas and involving 10% of the body surface area. Shave biopsies revealed an atypical epidermotropic infiltrate composed of hyperchromatic small to medium-sized lymphocytes with perinuclear halos and "tagging" along the dermal-epidermal junction. The immunophenotype was unusual in that the neoplastic lymphocytes showed complete loss of pan T-cell antigens along with expression of CD56, cytotoxic markers, and weak CD20. All other B-cell markers were negative. The combination of clinical findings, in addition to the histopathologic and immunophenotypic profile, were diagnostic of null T-cell phenotype MF with aberrant expression of CD56 and CD20. Null T-cell phenotype MF is very uncommon, can be diagnostically challenging, and can mislead the diagnosis of aggressive lymphoma subtypes.

Coexistence of large cell transformed mycosis fungoides and diffuse large B-cell lymphoma in one patient.

Diffuse large B-cell lymphoma (DLBCL) is the most common and aggressive subtype of non-Hodgkin lymphoma. The overall risk of developing DLBCL is increased in patients with other lymphomas, such as mycosis fungoides (MF). In this report, we present an 81-year-old female with early-stage MF who simultaneously progressed to tumor stage, large-cell transformed (LCT) MF and developed a primary DLBCL in a lymph node (LN). She presented with a tumor on her leg and new lymphadenopathy in her right axilla. Skin biopsy of the tumor revealed infiltration of large atypical CD3+, CD4+, and CD30+ cells, and a smaller portion of CD8+ cells in the dermis, consistent with LCT MF. Biopsy of the axillary LN revealed diffuse sheets of CD20+, BCL-2+, c-MYC+, and CD10- cells, highly suggestive of double expressor DLBCL. High-throughput sequencing revealed monoclonal T cells in the skin tumor and a monoclonal B-cell population in the LN. The above findings led to simultaneous diagnoses of LCT MF and nodal double expressor DLBCL. Our case demonstrates the importance of performing a full pathological workup in cutaneous T-cell lymphoma patients presenting with lymphadenopathy.

TOX, TWIST1, STAT4, and SATB1 protein expressions in early-stage mycosis fungoides.

BACKGROUND: Diagnosis of early mycosis fungoides (eMF) is challenging and often delayed as many of its clinical and histopathologic features may mimic various benign inflammatory dermatoses (BIDs). The products of the thymocyte selection-associated high mobility group box (TOX), twist family BHLH transcription factor 1 (TWIST1), signal transducer and activator of transcription 4 (STAT4), and special AT-rich sequence-binding protein 1 (SATB1) genes function as transcription factors and are involved in the pathogenesis of MF. OBJECTIVES: We aim to determine the diagnostic value of TOX, TWIST1, STAT4, and SATB1 protein expressions in eMF. METHODS: This non-randomized, controlled, prospective analytic study was conducted by performing immunohistochemistry staining with TOX, TWIST1, STAT4, and SATB1 polyclonal antibodies in lesional skin biopsies of eMF and BID patients. Nuclear staining of lymphocytes was compared between eMF and BIDs, and the capacity of these antibodies to predict eMF was determined. RESULTS: Immunostainings with anti-TWIST1 showed an increase in protein expression (p = 0.003) and showed a decrease with anti-SATB1 antibodies in eMF compared to BIDs (p = 0.005) while anti-TOX and anti-STAT4 antibodies did not exhibit significant differences (p = 0.384; p = 0.150). Receiver operating characteristic analysis showed that immunohistochemical evaluations of TWIST1 and SATB1 protein expressions can differentiate eMF (area under the curve [AUC]: 0.728, 95% confidence interval [CI]: 0.605-0.851, p = 0.002; AUC: 0.686, 95% CI: 0.565-0.807, p = 0.013). CONCLUSIONS: TWIST1 and SATB1 are potential diagnostic markers for the histologic diagnosis of eMF.

Assessing T-cell receptor clonality by next-generation sequencing in atypical cutaneous lymphoid infiltrates and cutaneous T-cell lymphoma: A scoping review.

The diagnosis of cutaneous T-cell lymphoma (CTCL) remains challenging. Demonstration of a clonal T-cell population using T-cell receptor (TCR) gene rearrangement studies by next-generation sequencing (NGS) has been explored in several studies. This review summarizes the current literature on NGS-based sequencing methods for the assessment of TCR clonality in the evaluation of atypical cutaneous lymphoid infiltrates and CTCL on behalf of the American Society of Dermatopathology Appropriate Use Criteria Committee (lymphoproliferative subgroup). PubMed was searched for relevant articles, including CTCL and NGS, for clonality from 1967 to 2022. Thirteen studies were included in the analysis. The skin was the most commonly assayed compartment with TCR NGS. Sensitivity for TCR NGS in the skin ranged between 69% and 100%, compared to 44%-72% for polymerase chain reaction (PCR)-capillary electrophoresis. Specificity for TCR NGS in the skin ranged from 86% to 100%, compared to 77%-88% for PCR capillary electrophoresis. TCR NGS was also reported to have potential prognostic value in CTCL and can also be used to detect relapse and/or minimal residual disease after treatment.

Early Organ Metastasis in Granulomatous Mycosis Fungoides: A Systematic Review.

BACKGROUND: Granulomatous mycosis fungoides (GMF) is a rare form of cutaneous T-cell lymphoma characterized by a granulomatous inflammatory infiltrate. OBJECTIVE: The impact of granulomatous inflammation on the prognosis of the disease remains controversial as there have been both favorable and unfavorable outcomes documented. METHODS: We performed a systematic review of 116 GMF cases previously described in the literature. RESULTS: In contrast to the classic Alibert-Bazin type of mycosis fungoides (MF), cutaneous lesions in GMF tend to involve distal extremities (lower legs, feet, hands) early in the disease course. In the literature, 30% of GMF patients developed organ metastasis, most frequently to the lung. The median time to stage progression was 25 months. CONCLUSION: GMF is an aggressive form of MF. Therefore, screening for distant metastases should be considered at presentation and repeated during follow-up.

Clinical, histopathological and immunohistochemical evaluation of ultraviolet A1 treatment in early-stage mycosis fungoides.

BACKGROUND/PURPOSE: Mycosis fungoides (MF) is the most common variant of cutaneous T-cell lymphomas primarily involving the skin. Early-stage MF is characterised by non-specific skin lesions and non-diagnostic biopsies. While skin-focused treatments, such as PUVA and narrowband UVB (nbUVB), are the most frequently recommended treatments, the UVA1 efficacy has been researched in recent years. The purpose of this study was to evaluate the clinical, histopathological and immunohistochemical aspects of UVA1 treatment in patients with early-stage MF. METHODS: The modified severity weighted assessment scale (mSWAT) was used for total skin body scoring before and after treatment. Skin punch biopsies were taken from the patients before and after treatment. UVA1 therapy was performed five times each week. RESULTS: This study included 26 patients with early-stage MF. The total number of UVA1 sessions varied between 15 and 34. Complete response was observed in 8 (30.8%) of 26 patients (30.8%). The median mSWAT score decreased statistically significantly from 7.1 to 2.0 after treatment (p < .001). Histopathological complete response was observed in 2 (9.5%) of 21 patients. A statistically significant decrease in dermal interstitial infiltrate was observed on histopathological examination after treatment (p = .039). Epidermal CD4/CD8 levels decreased statistically significantly higher from a median of 2.5-1.2 in the complete clinical response group after treatment (p = .043). CONCLUSION: According to our results, UVA1 treatment has an effect on early-stage MF in terms of clinical, histopathological and immunohistochemistry.

Frequency of skin cancer among psoriasis, vitiligo, and mycosis fungoides patients treated with narrowband ultraviolet B phototherapy.

BACKGROUND: Narrowband ultraviolet B (NB-UVB) phototherapy is a popular and relatively contemporary treatment option. However, only a few studies to date have explored the potential risk of skin cancer following NB-UVB treatment. OBJECTIVE: This study aimed to investigate the potential long-term risk of skin cancer in patients treated with NB-UVB. METHODS: This cohort study included patients with psoriasis, vitiligo, and mycosis fungoides treated with NB-UVB at two university hospitals in Israel in 2000-2005. Patients were followed up for skin cancer for at least 10 years. Data were extracted from the hospital and community medical records. RESULTS: A total of 767 patients were included in this study: 509 with psoriasis, 122 with vitiligo, and 136 with mycosis fungoides. The mean follow-up duration was 13 years. Among these patients, 4.43% developed skin cancer during the follow-up (3.93% had psoriasis, 2.46% had vitiligo, and 8.09% had mycosis fungoides). Old age and fair skin type were the only significant independent risk factors for skin cancer. There was no significant difference in the mean number of NB-UVB treatments among patients who developed skin cancer and those who did not (99.09 vs. 94.79, respectively). CONCLUSION: No association was observed between the number of NB-UVB treatments and carcinogenesis in any study group. Age is a significant risk factor, and older patients treated with NB-UVB should be followed up carefully.

Estimation of serum and tissue level of interleukin-15 (IL-15) and IL-15 receptor alpha (IL-15Rα) in mycosis fungoides before and after phototherapy: An interventional cohort study.

BACKGROUND: Mycosis fungoides (MF) is a chronic, highly recurrent cutaneous T-cell lymphoma, whose pathogenesis has not yet been fully elucidated. Interleukin-15 was previously highlighted as a viability factor for cutaneous T-cell lymphoma with previous studies shedding light on its role in pathogenesis of MF and its plausibility as a potential therapeutic target. OBJECTIVE: This study was conducted to evaluate serum and tissue expression of IL-15 and IL-15Rα in early cases of MF (IA, IB, IIA) at baseline and following phototherapy. MATERIALS AND METHODS: Fourteen early MF cases were recruited. Samples were withdrawn prior to starting phototherapy treatment and following near complete clearance of the biopsied lesion or after a maximum of 36 sessions of phototherapy. Samples were assessed for change in expression of IL-15 and IL-15 Rα levels following treatment, whose levels were compared to healthy controls. RESULTS: Serum and tissue levels of IL-15 and IL-15Rα in early MF cases were significantly higher at baseline than their levels following phototherapy treatment and higher than healthy controls. However, they dropped significantly following treatment with no statistical difference between treated cases and controls, apart from serum IL-15Rα that remained significantly elevated than controls. CONCLUSION: Interleukin-15 and its receptor alpha appear to contribute to the pathogenesis of MF, being significantly elevated than healthy controls, which were normalized following phototherapy treatment, apart from serum IL-15Rα, which remained elevated. Controlling IL-15/IL-15Rα expression is a newly proposed mechanism of action of phototherapy in MF.

Phenotypic heterogeneity of mycosis fungoides cells leads to the difficulties in determining tumour origin.

Mycosis fungoides (MF) is a low-grade malignant cutaneous T-cell lymphoma that originates from memory T cells. It typically follows a unique and relatively indolent disease course. MF is used to be characterized by a tissue-resident memory T cell (TRM) phenotype, although recent molecular research has revealed its complexity, casting doubt on the cell of origin and the TRM-MF paradigm. Recent clonal heterogeneity studies suggest that MF may originate from immature early precursor T cells. During development, the tumour microenvironment (TME) influences tumour cell phenotype. The exact origin and development trajectory of MF remains elusive. Clarifying the origin of MF cells is vital for accurate diagnosis and effective treatment.

Psychological Distress and Treatment Outcome in Patients With Early-Stage Mycosis Fungoides.

BACKGROUND: Skin diseases have been shown to worsen psychological distress, which, in turn, may be detrimental to treatment outcomes. Both the impact of psychological distress on response to treatment in mycosis fungoides (MF) and the effect of treatments on psychological well-being are unclear. OBJECTIVES: To evaluate (1) the association between pretreatment psychological morbidity and treatment outcome in early-stage MF and (2) the impact of response to treatment on psychological well-being. METHODS: This was a prospective cohort study of patients with early-stage MF who started a new stage-directed treatment for their disease. The response was determined using the modified severity-weighted assessment tool, and psychological distress was assessed using the 12-item General Health Questionnaire (GHQ-12) and Penn State Worry Questionnaire (PSWQ). Participants were followed for 1 year. RESULTS: In all, 24 consecutive patients were recruited. Objective response rate was 71% (17/24), consistent with existing literature. Prior to treatment, 9 patients (38%) had clinically significant psychological distress on the GHQ-12, while 8 (33%) demonstrated high-level worry on the PSWQ. Of these patients, 6 had pathologic scores on both instruments. Patients with significantly less baseline anxiety/depression on the GHQ-12 responded better to treatment than patients with higher levels (P = .004). In addition, responders' mean GHQ-12 scores decreased by 39% and their PSWQ scores by 17%, whereas nonresponders' GHQ-12 scores increased by 93% (P = .042) and their PSWQ scores by 11% (P = .019). CONCLUSIONS: These findings suggest that (1) baseline psychological distress is associated with worse outcomes in patients with early-stage MF and that (2) effective treatment improves psychological morbidity.

Evaluation of mortality, prognostic parameters, and treatment efficacy in mycosis fungoides.

BACKGROUND AND OBJECTIVES: Mycosis fungoides (MF), the most common primary cutaneous T-cell lymphoma, is characterized by a variable clinical course, presenting either as indolent disease or showing fatal progression due to extracutaneous involvement. Importantly, the lack of prognostic models and predominantly palliative therapy settings hamper patient care. Here, we aimed to define survival rates, disease prediction accuracy, and treatment impact in MF. PATIENTS AND METHODS: Hundred-forty MF patients were assessed retrospectively. Prognosis and disease progression/survival were analyzed using univariate Cox proportional hazards regression model and Kaplan-Meier estimates. RESULTS: Skin tumors were linked to shorter progression-free, overall survival and a 3.48 increased risk for disease progression when compared to erythroderma. The Cutaneous Lymphoma International Prognostic Index identified patients at risk in early-stage disease only. Moreover, expression of Ki-67 >20%, CD30 >10%, CD20+, and CD7- were associated with a significantly worse outcome independent of disease stage. Only single-agent interferon-α and phototherapy combined with interferon-α or retinoids/bexarotene achieved long-term disease control in MF. CONCLUSIONS: Our data support predictive validity of prognostic factors and models in MF and identified further potential parameters associated with poor survival. Prospective studies on prognostic indices across disease stages and treatment modalities are needed to predict and improve survival.

Mogamulizumab-associated rash - Case series and review of the literature.

Mogamulizumab, a monoclonal antibody directed against CC chemokine receptor 4, is approved as a second-line treatment of mycosis fungoides and Sézary syndrome. One of the most common side effects is mogamulizumab-associated rash (MAR), which can present in a variety of clinical and histological types. Clinically, it can be difficult to differentiate between MAR and progression of the underlying disease, so histological examination is crucial for clinicopathological correlation. Current data analyses suggest that MAR is more common in patients with Sézary syndrome and is associated with a significantly better response to treatment, making the distinction from disease progression particularly important. The management of MAR depends on its severity, and therapy may need to be paused. This article presents three cases from our clinic and reviews the current literature on MAR. It emphasizes the importance of understanding MAR in the management of patients with cutaneous lymphomas.

Cutavirus Infection in Large Plaque Parapsoriasis, a Premalignant Condition of Mycosis Fungoides.

BACKGROUND: Cutavirus (CuV) is associated with mycosis fungoides; however, the CuV status in parapsoriasis en plaques (PP), a premalignant inflammatory condition of mycosis fungoides, has not been fully delineated. METHODS: Fifty-five Japanese patients with chronic inflammatory skin diseases, including 13 patients with PP, were studied. RESULTS: CuV DNA was detected significantly more frequently in biopsies of the lesional skin from patients with PP (38% [4/13]) than in those from patients with other inflammatory skin diseases (2% [1/42]; P = 0.009). All CuV-positive PP cases were of the large plaque parapsoriasis (LPP) subtype. The viral loads ranged from 83,450 to 2,164,170 copies/103 cells. We recovered near-full-length CuV sequences from the CuV-positive LPP biopsies, all of which were of the Japanese/Asian genotype. The CuV genome appeared to be present within lymphoid cells infiltrating the epidermis and dermis. CuV NS1 and VP1 gene transcripts were also detected in the affected tissues. CONCLUSIONS: The preferential detection of high levels of CuV DNA with the expression of viral mRNA suggests a potential role for CuV in the pathogenesis of LPP, making it necessary to study further the impact of CuV, especially regarding the viral genotype, on the outcomes of patients with CuV-positive LPP.