Search Results (89)

Introduction: Cutaneous T cell lymphoma (CTCL), most commonly known as mycosis fungoides (MF), is characterized by an increasingly immunosuppressive tumor microenvironment (TME) as the disease progresses. Cancer-associated fibroblasts (CAFs) are key stromal components that support a permissive niche, in part through the secretion of small extracellular vesicles (sEVs), predominantly exosomes, that mediate intercellular communication. We investigated the immunomodulatory role of exosome-enriched sEVs derived from MF fibroblasts (MF-Fs) compared to normal fibroblasts (N-Fs). Materials and Methods: Primary MF-Fs from early-stage MF biopsies and N-Fs from healthy skin were cultured in vitro. sEVs enriched with exosomes were isolated by ultracentrifugation and characterized by flow cytometry (CD81), electron microscopy, Nanosight analysis, and protein quantification, and their uptake by normal peripheral blood mononuclear cells (nPBMCs) was confirmed using PKH26-labeled sEVs. nPBMCs, monocytes, CD4⁺ and CD8⁺ T cells from healthy donors were exposed to MF-F or N-F sEVs. Cell viability was assessed using MTT and trypan blue exclusion assays. Mass cytometry (CyTOF) profiled immune subsets and regulatory proteins for preliminary observation. Monocyte polarization was evaluated by flow cytometry for M1 (CD80, CD86) and M2 (CD163, CD206) markers and PD-L1 expression; M1/M2-associated cytokines and sEV-microRNAs were quantified by qRT-PCR. Results: Both MF-F and N-F sEVs were internalized by nPBMCs and reduced their viability, with a more pronounced effect observed for MF-F sEVs. In nPBMCs, MF-F sEVs also increased the frequency of M2-like macrophages, decreased M1 polarization, and enhanced PD-L1 expression. In primary monocytes, MF-F- compared with N-F-derived sEVs upregulated M2-associated cytokines (IL-10, TGF-β), increased PD-L1 expression, and generated M2-like cells that suppressed CD4⁺ and CD8⁺ T cell viability. Conclusions: MF-F sEVs promote an immunosuppressive TME and represent potential therapeutic or biomarker targets in MF. Full article

Cutaneous hematologic neoplasms in children are relatively rare and encompass a wide range of lymphoproliferative and myeloproliferative disorders. This review explores and updates the classification, clinical presentation, diagnostic challenges, histopathology, and management of pediatric lymphomas, lymphoproliferations, and leukemias that may be seen in the skin. The most frequent of them are lymphomatoid papulosis (LyP) and mycosis fungoides (MF), and are discussed first, with a particular focus on differential diagnosis and overlaps with benign lesions—mainly pityriasis lichenoides—which raises questions regarding the delineation of these entities and their potential interconnection. It is important to underline that most cutaneous lymphoproliferations are indolent in children: primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder, subcutaneous panniculitis-like T-cell lymphoproliferation (non-associated with HAVCR2 mutations), primary cutaneous marginal zone lymphoproliferative disorder, and EBV-related lymphoproliferative disorders. However, aggressive hematologic malignancies, although rarer, must not be missed; these are mostly leukemias (but not all forms) and blastic plasmacytoid dendritic cell neoplasm. We emphasize the importance of clinical–pathological correlation, with clonality studies playing a crucial role in some cases. Management strategies are briefly reviewed, ranging from skin-directed therapies like phototherapy and corticosteroids to systemic treatments for more aggressive forms of leukemia cutis and lymphomas. Full article

Cutaneous pseudolymphomas are benign reactive lymphoid proliferations that often mimic cutaneous lymphomas both clinically and histologically. A diverse array of inflammatory, infectious, and drug-induced dermatoses can closely resemble cutaneous T-cell lymphomas (CTCLs), particularly mycosis fungoides (MFs), posing significant diagnostic challenges. These mimickers may show histopathological features such as epidermotropism, dense lymphocytic infiltrates, or even clonality, making accurate differentiation crucial to avoid overtreatment. This review endeavors to comprehensively discuss the clinicopathologic features of the various inflammatory and infectious dermatoses that may simulate CTCL, drawing on illustrative examples across disease categories. By highlighting important comparative features and emphasizing the importance of clinicopathologic correlation, this review outlines practical strategies for distinguishing true lymphoma from its inflammatory mimics. Full article

Cutaneous T-cell lymphoma (CTCL), primarily mycosis fungoides (MF) and Sézary syndrome (SS), has long been characterized as a neoplasm of mature memory T cells, based on monoclonal T-cell receptor (TCR) rearrangements and tissue-resident memory (TRM)/central memory (TCM) T-cell phenotypes. This review synthesizes converging population-genetic, multi-omic, and single-cell evidence to argue that this characterization is incomplete and that a progenitor-based model better accounts for the full spectrum of disease biology. We present evidence that initiating mutations arise in hematopoietic stem or early lymphoid progenitor survive thymic selection, and diversify after TCR assembly, resulting in branched evolution across both blood and skin. In SS, paired analyses reveal > 200 shared variants between CD34⁺ progenitors and Sézary cells, as well as signal-joint T-cell receptor excision circle (sjTREC) positivity, providing direct progenitor-level evidence. In MF, convergent signals, multiple malignant clonotypes per lesion, greater blood–skin than skin–skin clonotype overlap, and compartment-specific CNV subclones, implicate hematogenous seeding and reseeding. Population-scale lymphoid clonal hematopoiesis and lymphoid-pattern mosaic chromosomal alterations define a compatible antecedent state. Spatial single-cell atlases and trajectory analyses map site-conditioned programs in skin, including Th2-skewed cytokines, microbial responses, and UV signatures, that select and expand subclones and explain inter- and intra-patient heterogeneity. This framework reconciles mature immunophenotypes with upstream initiation and clarifies why compartment-focused therapies often reshape rather than eradicate disease. It yields testable predictions and actionable implications: trials should pair multicompartment cytoreduction with strategies that attenuate progenitor-derived reservoirs, restore immune balance, and repair skin barrier dysfunction. A progenitor-initiated, niche-adapted model provides a coherent scaffold for more durable control in CTCL. Full article

Background and Objectives: Mycosis fungoides (MF) is the predominant subtype of cutaneous T-cell lymphoma, whereas large plaque parapsoriasis (LPP) closely resembles early-stage MF, making differential diagnosis challenging. Immune markers, such as CD47, CD163, and B7-H3, play crucial roles in tumor immune evasion and macrophage polarization. However, their expression profiles and potential diagnostic or prognostic implications in early-stage MF and LPP remain poorly defined. Therefore, this study aimed to evaluate the expression of CD47, CD163, and B7-H3 in early-stage MF and LPP and analyze their associations with clinicopathological characteristics and patient outcomes. Materials and Methods: This retrospective study evaluated the immunohistochemical expression of CD47, CD163, and B7-H3 in 46 patients with early-stage mycosis fungoides (MF) and 46 patients with large plaque parapsoriasis (LPP). Expression levels were assessed using an immunoreactivity scoring system and analyzed for their associations with clinical parameters and disease-free survival (DFS). The study included patients diagnosed and followed at Sivas Cumhuriyet University between 1 March 2015 and 31 March 2025. Results: High CD47 expression was detected in 72.7% of MF patients, high B7-H3 expression in 45.7%, and high CD163 expression in 46.7% compared with LPP patients (p < 0.001). These markers showed positive correlations, and elevated expression, especially of B7-H3 and CD163, was associated with shorter disease-free survival in univariate analysis. Conclusions: The higher expression of CD47, CD163, and B7-H3 in early-stage MF compared with LPP suggests that these markers may contribute to the differential diagnosis and could represent potential therapeutic targets; however, their independent prognostic value requires confirmation in larger studies. Full article

Mycosis fungoides (MF) is a rare primary cutaneous T-cell lymphoma (pCTCL) that generally has an indolent course with a favorable prognosis. However, numerous clinical variants have been described that differ substantially from classic Alibert–Bazin MF, resulting in altered prognosis, treatment response, and patient outcomes. This narrative review considers rare MF variants—bullous, ichthyosiform, hypopigmented, folliculotropic, poikilodermatous, granulomatous, granulomatous slack skin, pagetoid reticulosis and syringotropic MF—with emphasis on practical diagnostic approaches for clinicians. Given that MF can mimic more than 50 different dermatoses and is frequently associated with prolonged diagnostic delay, we provided detailed clinical and dermoscopic features that should raise diagnostic suspicion and guide biopsy decisions. We discussed extensive differential diagnoses for each variant and highlighted MF’s status as dermatology’s “great imitator.” Additionally, we addressed the risk of second primary malignancy in patients with MF, as well as the genetic and microenvironmental factors proposed to contribute to its clinical heterogeneity. Furthermore, we evaluated existing classification systems and suggested future directions that integrate molecular data and tumor biology to improve prognostic assessment and guide therapeutic decision-making. Full article

Background/Objectives: Mycosis fungoides (MF) and Sézary syndrome (SS) are chronic cutaneous T-cell lymphomas frequently associated with pruritus, psychological distress, and impaired quality of life (QoL). While the impact of MF/SS on patients’ quality of life is well recognized, data on the burden experienced by cohabitants remain limited. The aim of this study was to assess dermatology-specific quality of life in patients with MF/SS and their cohabitants and to explore its associations with pruritus severity, depressive symptoms, and disease stage. Methods: This cross-sectional study included 25 patient–cohabitant pairs (25 patients with MF/SS and their cohabitants living in the same household) recruited at a tertiary dermatology center. Patients completed the Dermatology Life Quality Index (DLQI), Beck Depression Inventory I (BDI-I), and pruritus intensity scales (Numeric Rating Scale and Visual Analogue Scale), whereas cohabitants completed the Family Dermatology Life Quality Index (FDLQI) to assess the family burden of the disease. Associations between quality-of-life measures, clinical characteristics, pruritus, and depressive symptoms were analyzed. Results: Patients reported moderate impairment in dermatology-specific quality of life (mean DLQI score of 9.3 ± 6.1), which was significantly greater in patients with advanced-stage disease (p = 0.022). Cohabitants also experienced moderate impairment in quality of life (mean FDLQI score of 8.0 ± 4.8), independent of disease stage. DLQI scores showed significant positive correlations with pruritus severity, depressive symptoms, and cohabitants’ FDLQI scores. Pruritus severity was a key determinant of impaired quality of life but did not differ significantly between disease stages. Conclusions: MF/SS are associated with a substantial multidimensional burden affecting both patients and their cohabitants. Quality-of-life impairment in family members correlates closely with patient-reported symptoms and well-being, supporting the concept of MF/SS as conditions affecting the patient–family unit. Incorporating caregiver perspectives and systematic symptom assessment may improve holistic management of MF/SS. Full article

Background/Objectives: Mycosis fungoides (MF) and Sézary syndrome (SS) are cutaneous T-cell lymphomas (CTCLs) with variable clinical outcomes. Peripheral blood (PB) involvement in MF/SS is an independent predictor of prognosis. Accurate laboratory determination of PB involvement by MF/SS cells, however, is an ongoing challenge. Both flow cytometry (FC) and morphology-based quantification are limited by the overlap of CTCL cells and reactive T-cells. This study looks at the optimization over time of CTCL blood burden evaluation. Methods: This retrospective study reviews CTCL blood assessment at Northwestern Memorial Hospital from 2012 to 2021. Test ordering and reporting practices for morphology-based Sézary cell counts and FC were evaluated. For each assay, quantitative and qualitative results were analyzed and compared including percentages and absolute counts of abnormal T-cell populations and pathologist interpretations. Results: A total of 514 patients were evaluated, with increasing numbers of both tests ordered over time. FC quantitative metrics showed a moderate to high correlation with morphology metrics, especially for absolute CD4+/CD7− counts (correlation coefficient = 0.901, p-value < 0.001). Qualitative pathologist interpretations had moderate agreement between methods (kappa = 0.58). The recent addition of TRBC1 clonality assessment to our FC assay further optimizes the evaluation for CTCL blood burden. Conclusions: Flow cytometry offers a reliable approach for blood staging in MF/SS, and morphologic assessment may be redundant. This study provides a foundation for designing a new FC approach with TRBC1. This comprehensive review of the evolution of our laboratory practices may serve as a guide for other institutions with similar clinical needs. Full article

Background/Objectives: Hypopigmented mycosis fungoides (hMF) is a rare variant of mycosis fungoides (MF) often seen in younger patients and individuals with darker skin phototypes. The lesions develop as hypopigmented patches or plaques, and they are usually asymptomatic and respond well to topical treatment or phototherapy. Methods: We provide a systematic review on hMF with onset at or beyond 30 years of age, based on SCOPUS, PubMed, and Embase databases. A total of 13 original articles, totaling 34 patients, were included in this review. Evidence was limited to case reports and small series; PROSPERO registration is CRD420251181894. Results: The majority of cases did not progress beyond stage IB and commonly used treatment methods, including topical corticosteroids and phototherapy. In three patients, a progression of the disease occurred, and in two of them it was fetal. Among patients receiving phototherapy, PUVA therapy achieved complete remission more often than UVB (13 out of 17 cases vs. 8 out of 16 cases). Although recurrences occurred with both treatments, they were less frequent, and relapses took longer to develop in the PUVA group. Conclusions: In this cohort, PUVA appeared to be associated with higher complete response rates and longer remission duration than UVB. However, this advantage of PUVA is derived from low-level evidence and should be confirmed in prospective comparative studies. Full article

Background/Objectives: Advanced-stage mycosis fungoides (MF) and Sézary syndrome (SS) are aggressive forms of cutaneous T-cell lymphoma (CTCL) for which treatment options are limited and prognosis is poor. Brentuximab vedotin (BV), an anti-CD30 antibody–drug conjugate, has demonstrated high response rates in patients with CD30 expression ≥ 10%. However, data on its efficacy in cases with low CD30 expression (<10%) remain scarce. Methods: This retrospective analysis evaluated the real-world efficacy of BV in patients with advanced-stage MF/SS and low CD30 expression. A retrospective analysis was conducted on 32 patients across 11 German CTCL expert centers. All patients had advanced-stage MF or SS with CD30 expression < 10% and received BV at the standard dose. Treatment response was assessed using EORTC-ISCL criteria. Results: All patients had received prior systemic therapies (median: 3) with 36% having undergone prior mono- or polychemotherapy. The study population included 30 MF (stage IIB) and two SS cases. The overall response rate (ORR) in this population was 53.1% (17/32). A complete response (CR) was achieved in 12.5% (4/32), a partial response (PR) was achieved in 40.6% (13/32), stable disease (SD) was seen in 18.8% (6/32), and progressive disease (PD) was seen in 28.1% (9/32). The median progression-free survival (PFS) was 4.0 months (arithmetic mean: 6.38; range: 0.5–15.5), and the median time to next treatment (TTNT) was 7.25 months (arithmetic mean: 7.30; range: 2.00–15.5). Conclusions: BV demonstrated encouraging activity in heavily pretreated advanced MF/SS with low CD30 expression, achieving an ORR comparable to that observed in patients with higher CD30 levels. While response rates were similar, PFS was shorter. These findings suggest that BV remains a potential therapeutic option in this patient population and merits further prospective investigation. Full article

Cutaneous T-Cell Lymphomas (CTCL) are a heterogenous group of T-cell malignancies in the skin and have poor treatment outcomes in advanced stages. CD5, a surface glycoprotein expressed on most mature T cells, has emerged as a promising target for chimeric antigen receptor (CAR) T-cell therapy in systemic T-cell lymphomas. However, its expression profile in CTCL and relevance for targeted therapy remain unclear. Notably, in CTCL, the cell surface expression of receptors, such as CD7 and CD26, tends to become downregulated on the surfaces of malignant T cells In this study, we analyzed single-cell RNA sequencing (scRNA-seq) data from patients at two institutions with mycosis fungoides (MF), the most common subtype of CTCL with a predominantly CD4 phenotype. We utilized 5 patch/plaque MF skin biopsies (majority from early-stage patients), 8 MF tumor biopsies (all from advanced-stage patients), and 8 healthy control biopsies to evaluate lesion-specific CD5 gene expression on CD4 T cells. We found that CD5 was significantly increased in malignant MF CD4 T cells compared to healthy control CD4 T cells (21.1% of MF CD4 T cells expressed CD5 vs. 5.2% of healthy control CD4 T cells, respectively). In subgroup analysis, patch/plaque stage MF biopsies showed higher expression of CD5 in CD4 T cells than tumor stage MF biopsies. Notably, 94.3% of malignant CD4⁺ T cells in tumor stage MF lesions exhibited complete CD5 loss compared to only 76.6% in patch-plaque MF lesions, suggesting antigen escape in tumor stage disease. These findings demonstrate that CD5 expression in CTCL is dynamic and varies based on lesion type. Our work suggests CD5 may be a viable therapeutic target in MF with patch/plaque presentations but may not be as effective in advanced stages of MF with tumor presentations. This work informs CD5 gene expression in MF based on clinical lesion type and further information is needed to clarify clinical implications as a future therapeutic target. Full article

Background/Objectives: High-frequency ultrasonography (HFUS) has gained increasing attention in dermatology as a non-invasive imaging technique capable of visualizing cutaneous structures with high resolution. In cutaneous T-cell lymphomas (CTCL), including mycosis fungoides (MF)/Sézary syndrome (SS), HFUS may provide an objective method for assessing disease activity and monitoring treatment response. This study aimed to evaluate the clinical utility of HFUS in detecting therapy-induced changes in subepidermal low-echogenic band (SLEB) thickness. Methods: We conducted a prospective, single-center study between May 2021 and May 2025. Thirty-three patients with histologically confirmed MF (n = 31) or SS (n = 2) underwent HFUS at baseline and after 4–8 weeks of treatment. SLEB thickness was measured before (E1) and after early treatment (E2). Patients received systemic agents, phototherapy, or topical regimens. Statistical analysis included mixed-model ANOVA with repeated measures to assess SLEB changes, and post hoc tests were applied to explore the influence of therapy type, age, and gender. Results: Among 31 evaluable patients with MF, HFUS revealed a significant reduction in SLEB thickness after treatment (0.90 ± 1.10 mm vs. 0.69 ± 0.89 mm; F(1,29) = 8.88, p = 0.006, η² = 0.23). The type of early therapy (systemic vs. topical) did not significantly affect outcomes (p = 0.452). Age emerged as a relevant factor: patients ≥ 66 years exhibited higher baseline SLEB values and a significant reduction post-treatment (p < 0.001), whereas no comparable effect was observed in younger patients. Gender did not significantly influence SLEB changes. Conclusions: HFUS is a sensitive and clinically applicable imaging tool for monitoring treatment response in MF/SS. Reductions in SLEB thickness were observed across therapeutic modalities and aligned with early clinical improvement. HFUS may serve as a valuable adjunct to standard clinical and histopathological evaluation in the routine management of MF/SS. Full article

Background: Mycosis fungoides (MF) is a rare cutaneous T-cell lymphoma (CTCL) that presents clinically on the skin as patches, plaques, or tumors. MF often mimics benign inflammatory conditions which leads to difficult and delayed diagnosis, worsening prognosis despite available treatment options. This study seeks to improve diagnosis and identify potential therapeutic targets by better characterizing MF’s genetic landscape using the AACR Project GENIE dataset. Methods: Retrospective analysis of MF cases was conducted using the AACR Project GENIE database accessed from cBioPortal (v17.0-public) on 5 June 2025. Data analysis included identifying recurrent somatic mutations, assessing patterns of mutation co-occurrence and mutual exclusivity using non-parametric tests with Benjamini–Hochberg False Discovery Rate (FDR) correction, and examining enrichment of specific mutations based on sex and race, with significance of p < 0.05. Results: Recurrent alterations included FAT1 (28.2%), KMT2D (19.2%), TP53 (13.5%), JAK3 (11.5%), and SETBP1 (11.5%), highlighting the role of Wnt signaling, epigenetic dysregulation, the p53 pathway, and JAK/STAT signaling in MF pathogenesis. Mutations with significant co-occurrence and enrichment in White, Black, and Asian populations were identified. Conclusions: The findings of this study provide a comprehensive understanding of MF’s molecular profile. The discovery of commonly mutated pathways (Wnt, p53, JAK/STAT, and epigenetic regulators) suggests potential targets for the development of future therapies. Furthermore, the enrichment of certain mutations based on race and patterns of alteration co-occurrence offer possibilities for patient-tailored treatment approaches. Full article

Introduction: Mycosis fungoides (MF) is the most common cutaneous T-cell lymphoma, often exhibiting loss of pan-T-cell markers such as CD2, CD3, CD5, and CD7. While these immunophenotypic alterations assist in diagnosis, their prognostic relevance in early-stage MF remains uncertain. This study aimed to determine whether immunohistochemical loss of T-cell markers CD2, CD3, CD5, and CD7 in patients with early-stage mycosis fungoides is associated with overall survival and progression-free survival. Methods: This retrospective included 83 patients with stage IA–IIA MF diagnosed between 2003 and 2012 at a single institution. Immunohistochemical staining of archived biopsy specimens was performed for CD2, CD3, CD5, and CD7. Loss of marker expression was defined as absence in ≥30% of lymphocytes. Clinical and histopathological data were correlated with survival and progression outcomes using Kaplan–Meier curves and log-rank tests. Results: Loss of at least one T-cell marker was identified in 66% of patients, most commonly CD7 (72%), followed by CD5 (11%) and CD2 (11%). No cases showed loss of CD3 expression. CD7 loss was significantly associated with shorter progression-free survival (p < 0.05), but not with overall survival. No significant associations were found between CD2 or CD5 loss and either survival or disease progression. Conclusions: CD7 loss was the only immunohistochemical abnormality significantly associated with earlier disease progression in early-stage MF, suggesting a potential prognostic role. In contrast, loss of CD2 and CD5 did not affect survival or progression, and CD3 was preserved in all cases. These findings highlight the value of incorporating CD7 status into prognostic assessment, although larger studies are needed to confirm its utility. Full article

Primary cutaneous lymphomas (PCLs), including cutaneous T-cell lymphomas (CTCL) and primary cutaneous B-cell lymphomas (PCBCL), are a diverse group of non-Hodgkin lymphomas that primarily affect the skin. Radiotherapy (RT) plays a pivotal role in the treatment of these lymphomas, particularly for localized disease, due to its ability to deliver precise, skin-directed treatment. Mycosis fungoides (MF) and Sézary syndrome (SS), the most common subtypes of CTCL, often require skin-directed therapies such as electron beam therapy and superficial brachytherapy to manage localized lesions. Electron beam therapy, including total skin electron beam therapy (TSEBT), has been utilized for decades, offering high response rates but with the risk of cumulative skin toxicity. Recently, low-dose radiotherapy (LDRT) has gained attention as an effective alternative that reduces toxicity while maintaining durable responses. Superficial brachytherapy is another modality that delivers radiation through custom molds, allowing for homogeneous dosing over complex anatomical areas like the face. Both teleradiotherapy and brachytherapy have demonstrated high complete response rates, with low recurrence rates observed when higher doses are used. In the context of primary cutaneous B-cell lymphomas, such as primary cutaneous marginal zone lymphoma (PCMZL) and primary cutaneous follicle center lymphoma (PCFCL), radiotherapy also offers excellent local control, particularly for indolent subtypes. However, more aggressive subtypes, such as diffuse large B-cell lymphoma, leg type (PCDLBCL-LT), may require systemic therapies in addition to radiation. Overall, teleradiotherapy and brachytherapy are essential components of the therapeutic arsenal for primary cutaneous lymphomas, offering effective disease control with manageable toxicity, while ongoing research focuses on optimizing treatment strategies and exploring novel combinations with systemic therapies. Full article