Primary cutaneous lymphoma: recommendations for clinical trial design and staging update from the ISCL, USCLC, and EORTC.

The number of patients with primary cutaneous lymphoma (PCL) relative to other non-Hodgkin lymphomas (NHLs) is small and the number of subtypes large. Although clinical trial guidelines have been published for mycosis fungoides/Sézary syndrome, the most common type of PCL, none exist for the other PCLs. In addition, staging of the PCLs has been evolving based on new data on potential prognostic factors, diagnosis, and assessment methods of both skin and extracutaneous disease and a desire to align the latter with the Lugano guidelines for all NHLs. The International Society for Cutaneous Lymphomas (ISCL), the United States Cutaneous LymphomaConsortium (USCLC), and the Cutaneous Lymphoma Task Force of the European Organization for the Research and Treatment of Cancer (EORTC) now propose updated staging and guidelines for the study design, assessment, endpoints, and response criteria in clinical trials for all the PCLs in alignment with that of the Lugano guidelines. These recommendations provide standardized methodology that should facilitate planning and regulatory approval of new treatments for these lymphomas worldwide, encourage cooperative investigator-initiated trials, and help to assess the comparative efficacy of therapeutic agents tested across sites and studies.

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.

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.

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.

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.

Comparison of 2 T-Cell Receptor-γ Clonality Assays on Skin Biopsies Suspicious for Mycosis Fungoides.

ABSTRACT: PCR-based fragment analysis of the T-cell receptor (TCR) gene is used extensively in diagnostic labs to assess clonality in T-cell populations in multiple tissue sites. Of the numerous TCR assays that have been reported, studies assessing use on biopsies suspicious for mycosis fungoides specifically are lacking. We compared clonality findings from a previously run 2-tube/2-fluorochrome dye assay to a redesigned 1-tube/1-fluorochrome dye assay on formalin-fixed skin biopsies. Overall, the accuracy of the 2-tube assay was marginally better (75.7% vs. 71.4%), when using clinical history combined with histologic diagnosis as the gold standard. The 2-tube assay had better sensitivity (73.7% vs. 65.8%), while the 1-tube assay had superior specificity (93.8% vs. 87.5%). Clonality results were easier to interpret with the 1-tube assay. In nearly 19% of cases, a change of assays on the same biopsy resulted in a change of clonality interpretation. For laboratories that change TCR-γ clonality assays, follow-up biopsies for mycosis fungoides assessment may result in a change of diagnosis.

Cutaneous Involvement by Refractory Celiac Disease Type 2 Histologically Mimicking Mycosis Fungoides.

ABSTRACT: Refractory celiac disease (RCD) is a rare condition characterized by persistent malabsorptive symptoms and villous atrophy despite a gluten-free diet. While RCD type 1 has a normal intraepithelial lymphocyte phenotype, RCD type 2 is defined by the presence of immunophenotypically aberrant and monoclonal intraepithelial T lymphocytes, with a high propensity to transform to enteropathy-associated T-cell lymphoma (EATL). Although dermatological manifestations of celiac disease are common, presentation with cutaneous involvement by abnormal lymphocytes of RCD type 2 or EATL is rare, with few histologic descriptions in the literature. We describe the case of a 66-year-old man with a history of celiac disease presenting with a generalized, erythematous papular rash over his torso, upper arms, and legs. Biopsy of his skin lesions showed prominent hyperkeratosis with underlying spongiosis and interface change. Increased intraepithelial (epidermotropic) lymphocytes were observed, out of proportion to the level of spongiosis, but not overly atypical in appearance. Immunohistochemistry revealed an aberrant T-cell immunophenotype (CD3/2/7 positive; CD5/4/8 negative), raising suspicion for a cutaneous T-cell lymphoproliferative disorder. A duodenal biopsy demonstrated total villous atrophy with a morphologically bland population of epitheliotropic T lymphocytes showing the same aberrant immunophenotype. Similar cells were also identified by flow cytometry in the peripheral blood. In conjunction with the history of celiac disease, a diagnosis of RCD type 2 or 'EATL in situ' with cutaneous involvement was made. Cutaneous RCD type 2 or EATL should be considered as differential diagnoses in patients with a history of celiac disease and histopathology reminiscent of epidermotropic forms of cutaneous T-cell lymphoma.

Diagnostic Validation of Anti-TOX Antibody for Early-Stage Mycosis Fungoides Through Digital Analysis of Tissue Samples.

ABSTRACT: Mycosis fungoides (MF) has become one of the most difficult diagnostic challenges for both dermatologists and dermatopathologists because its clinical presentation and microscopic findings may mimic benign reactive processes, specifically those displaying histopathological features of interface dermatitis. The goal of our study was to prove with digital scanning and automated sample methodology through algorithmic analysis, combined with the utility of TOX marker a more precise, faster, and objective evaluation of each sample. Moreover, this would offer high levels of reproducibility with the possibility of establishing cut-off points, allowing us to distinguish between inflammatory dermatoses (ID) and MF. A retrospective longitudinal-descriptive and observational study was conducted to compare the diagnostic criteria (immunohistochemical studies of anti-TOX stain) in patients with clinical suspicion of MF by dividing them into 2 groups: samples with a positive biopsy for MF (MF group) and those with a negative biopsy, therefore diagnosed as an ID (control group). The algorithm assessed 5 selected areas with lymphocytic representative cellularity, and based on the intensity, nuclear staining was classified as 0 (negative), 1+ (weak/yellow), 2+ (moderate/orange), and 3+ (strong/scarlet red) nuclei. The results showed statistically significant differences ( P = 0.040) between the mean number of (2+) nuclei in the positive final diagnosis group (MF group) and the negative final diagnosis group (ID group).

Mycosis Fungoides Palmaris et Plantaris Mimicking "Dyshidrotic Eczema": A Case Report.

Mycosis fungoides palmaris et plantaris (MFPP) is a rare variant of mycosis fungoides (MF), a type of cutaneous T-cell lymphoma. MFPP primarily affects the palms and soles of the feet and is often misdiagnosed as dyshidrotic eczema due to its similar clinical presentation. This case report presents a middle-aged woman with MFPP whose initial presentation was mistaken for dyshidrotic eczema. Despite treatment with topical corticosteroids, the patient's lesions persisted, prompting further investigations that led to the diagnosis of MFPP. The patient was initiated on betamethasone dipropionate ointment and hydroxyzine for pruritus management, with a pivotal referral to oncology for comprehensive evaluation. This case highlights the importance of considering MFPP in the differential diagnosis of persistent eczematous lesions on the palms and soles, especially when treatment with topical corticosteroids is ineffective. J Drugs Dermatol. 2024;23(7):569-570.     doi:10.36849/JDD.8474.

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.

Milia en plaque on the shoulder as an early manifestations of mycosis fungoides.

Milia en plaque (MEP) is an uncommon skin condition identified as retroauricular confluent milium by Boulzer and Fouqet in 1903 [1]. It can be mistaken for other dermatoses like Favre-Racouchot nodular elastosis, steatocystoma multiplex, and nevus comedonicus. Milia en plaque can either be primary or secondary and is typically benign, often triggered by dermatological procedures like cryotherapy, as reported in this journal. In some cases, MEP can arise as a secondary manifestation of other diseases, including folliculotropic mycosis fungoides (FMF). Despite this association, there are few documented cases in the literature. Herein, we present a patient in whom MEP served as the initial clinical presentation of FMF; the treatment involved oral retinoids and phototherapy. Furthermore, we highlight distinctive features of both conditions. It is important to emphasize that early diagnosis and treatment of FMF are vital for the patient's quality of life. The presence of MEP can serve as a valuable indicator for identifying it.

[Translated article] Survival Analysis and Prognostic Factors in a Case Series of 148 Cutaneous T-Cell Lymphomas.

BACKGROUND AND OBJECTIVE: Cutaneous T-cell lymphomas (CTCL) such as mycosis fungoides (MF) and Sézary syndrome (SS) are rare lymphomas with varying prognoses. The aim of the study was to describe the survival of a cohort of patients with MF/SS and evaluate the prognostic factors impacting disease survival. MATERIALS AND METHODS: All cases of MF/SS diagnosed from 2008 through 2022 were retrospectively analyzed. The demographic variables, histological parameters, and analytical data were analyzed too. Progression-free survival (PFS) and disease-specific survival (DSS) were calculated. RESULTS: A total of 148 cases were included. A total of 121 (82%) and 27 cases were diagnosed with MF, and SS, respectively. A total of 37 patients (25%) experienced progression at some point disease progression. The median PFS and median DSS were 127 and 135 months, respectively. Age >60 years, diagnosis of SS, the presence of large cell transformation (LCT) at diagnosis, folliculotropism in early stages, high Ki-67 expression, the presence of the clonal T-cell receptor (TCR) in blood, elevated LDH and B2M levels, and advanced stages (IIB, IVA, T3, T4, N3/Nx) were associated with worse prognosis across the entire cohort. CONCLUSIONS: Stage IVA and the presence of LCT at diagnosis stood out as independent factors of unfavorable prognosis. LCT was the variable that most significantly impacted the patients' survival and was closely associated with tumor skin involvement and stage IIB.

Staging lymph nodes and blood at diagnosis in mycosis fungoides identifies patients at increased risk of progression to advanced stage: A retrospective cohort study.

BACKGROUND: Risk factors for progression to advanced-stage mycosis fungoides (MF) are poorly defined. METHODS: The authors performed a single-center, retrospective cohort study among patients with MF at an academic medical center from 1990 to 2020 to identify clinical variables associated with progression to advanced-stage MF (stage IIB-IVB), and 388 patients who had a clinicopathologic diagnosis of early stage (IA-IIA) MF were identified from their cutaneous lymphoma database. Baseline clinical characteristics, laboratory values, imaging, and blood flow cytometry or T-cell receptor gene rearrangement (TCR) data were collected. Logistic regression was used to assess risk factors associated with progression. RESULTS: Overall, 93 of 388 patients (24.0%) progressed to advanced stage. Patients who progressed had an increased risk of death (hazard ratio, 4.50; 95% CI, 2.89-7.00; p < .001). Progression was associated with a higher overall stage at diagnosis, tumor stage, lymph node stage, low-level blood involvement, as measured with TCR data and/or flow cytometry, and elevated lactate dehydrogenase (LDH). Limitations included missing data for LDH, imaging, peripheral blood TCR data, or flow cytometry assessed at diagnosis. CONCLUSIONS: Staging and baseline laboratory assessments with imaging, peripheral blood flow cytometry, TCR data, and LDH in patients who have newly diagnosed MF may identify those who are at risk for progression to advanced stage.

Cutaneous T-cell lymphoma-Focus on some problems, and some solutions.

Cutaneous lymphomas are a heterogeneous group of several distinct entities of lymphoproliferative diseases. The diagnosis of a cutaneous lymphoma is a challenge, and it is always the result of a careful analysis of several information's consisting of clinical history, clinical picture, histological and molecular analyses. For this reason, experts taking care of patients with a skin lymphoma need to know all the peculiar diagnostic elements very well, in order not to run into mistakes. In this article, we will focus the discussion on some issues as the skin biopsy (when and where). In addition, we will discuss the approach to the erythrodermic patient, whose differential diagnoses include mycosis fungoides, and Sézary syndrome, beside more frequent inflammatory conditions. Finally, we will address the issue of quality of life and the possible support of the suffering patient with a cutaneous lymphoma, well knowing that the current therapeutic possibilities are unfortunately limited.

Cutaneous T-cell lymphomas: 2023 update on diagnosis, risk-stratification, and management.

DISEASE OVERVIEW: Cutaneous T-cell lymphomas are a heterogenous group of T-cell neoplasms involving the skin, the majority of which may be classified as Mycosis Fungoides (MF) or Sézary Syndrome (SS). DIAGNOSIS: The diagnosis of MF or SS requires the integration of clinical and histopathologic data. RISK-ADAPTED THERAPY: TNMB (tumor, node, metastasis, blood) staging remains the most important prognostic factor in MF/SS and forms the basis for a "risk-adapted," multidisciplinary approach to treatment. For patients with disease limited to the skin, expectant management or skin-directed therapies is preferred, as both disease-specific and overall survival for these patients is favorable. In contrast, patients with advanced-stage disease with significant nodal, visceral or the blood involvement are generally approached with systemic therapies, including biologic-response modifiers, histone deacetylase inhibitors, or antibody-based strategies, in an escalating fashion. In highly-selected patients, allogeneic stem-cell transplantation may be considered, as this may be curative in some patients.

Clinical Outcomes of COVID-19 in Mycosis Fungoides and Sezary Syndrome.

INTRODUCTION: Haemato-oncologic patients are more susceptible to severe infections with SARS-CoV-2. We aimed to assess the clinical outcomes of SARS-CoV-2 infection among patients with Mycosis Fungoides and Sezary Syndrome (MF/SS). METHODS: The data were retrieved from anonymized electronic medical records of Maccabi Healthcare Services (MHS), the second-largest healthcare organization in Israel. Patients diagnosed with MF/SS were included in the study. COVID-19 PCR test results together with sociodemographic and clinical data were extracted and analyzed to evaluate the association of COVID-19 with clinical outcomes. RESULTS: In the period of 2020-2022, 1,472 MF/SS patients were included in the study. Among them, 768 (52%) had SARS-CoV-2 infection. The hospitalization rate was 2.9% and infection by the Delta variant was associated with the highest hospitalization rate (7.7%). The hospitalization rate was lower among fully vaccinated patients (p = 0.032) but higher for patients older than 65 (p < 0.001) and patients with SS (vs. MF) (p < 0.001) or COPD (p = 0.024) diagnosis. There was a tendency for decreased hospitalization among patients treated with nirmatrelvir + ritonavir within 5 days of infection, with a 79% risk reduction, although it was not statistically significant (p = 0.164). CONCLUSION: Patients with MF/SS do not necessarily have worse COVID-19 outcomes compared to the general population.

Papillary dermal elastolysis histopathology mimicking folliculotropic mycosis fungoides.

Papillary dermal elastolysis is a rare acquired disease of the elastic tissue that mainly affects elderly women with a clinical presentation of small firm papules in the neck, the supraclavicular areas and the upper back. Histopathologically, it is characteristic to find a complete or almost complete absence of elastic fibers in the papillary dermis with stains such as orcein or Verhoeff-Van Gieson. We present the case of an adult female patient presenting a clinical picture of years of evolution of elastic skin-colored papules on her neck, occasionally pruritic. Two biopsies were performed. In one of them an inflammatory infiltrate affecting the hair follicles was observed, and she was diagnosed with mycosis fungoides. The other biopsy showed a total absence of elastic fibers in the papillary dermis and was diagnosed as elastolysis of the papillary dermis. In early stages of papillary dermal elastolysis, a perivascular and periadnexal lymphocytic inflammatory infiltrate has been described, as is the case described above. It is important for dermatopathologist to know this atypical but possible presentation, as it may require a differential diagnosis with other entities such as follicular mycosis fungoides.

Clinical Features, Histological Characteristics, and Disease Outcomes of Mycosis Fungoides in Children and Adolescents: A Nationwide Multicentre Cohort of 46 Patients.

BACKGROUND: Our objective was to describe the clinical, histological characteristics, and disease outcome of a cohort of mycosis fungoides (MF) diagnosed during childhood including disease status at adulthood. METHODS: This is a retrospective multicentre survey of patients aged under 18 years at diagnosis with histologically confirmed MF. Patients' clinical and histological characteristics, treatments, and disease outcome (for patients followed for more than 12 months) were analysed. RESULTS: Forty-six patients were included (median age at diagnosis: 11 years; M:F sex ratio: 3:1) with 39 (85%) followed for at least 12 months. Thirty-nine patients (85%) had stage I MF. Hypopigmented patches were observed in 48% and folliculotropism in 43% patients. Immunophenotype of the skin infiltrate was predominantly CD8+ in 17% of patients. Initial management included a wait-and-see strategy in 6/39 (15%), skin-directed treatment in 27 (69%), and systemic treatment in 6 (15%) patients, respectively, with partial or complete clinical response (PR or CR) observed in 28 patients (72%). 14/39 patients (36%) relapsed after initial response. After a median follow-up period of 54 months, disease status at last news was PR or CR in 31/39 (79%), stable disease in 6 (15%), and progression in 2 (5%) patients. Histological transformation was observed in 3/39 (8%). Of the 15 patients followed until adulthood, 13 (87%) had persistent MF. DISCUSSION: This survey confirms the high frequency of hypopigmented and folliculotropic lesions and of CD8+ immunophenotype compared to adult MF patients. The long-term course is usually indolent but transformation may occur sometimes long after disease onset and the disease may persist during adulthood.

Pediatric Primary Cutaneous Lymphoma in China: A Retrospective Study.

BACKGROUND: The incidence and clinical features of primary cutaneous lymphoma (PCL) tend to differ by age, gender, geographical, and racial variation. All-aged and adult groups of PCL in various regions have been well demonstrated and compared, while the research concentrating on pediatric PCL is rare, especially in Asian countries. OBJECTIVE: The aim of this study was to investigate the clinical characteristics of PCL in pediatric population at a single center in China. METHODS: We conducted a retrospective study of 101 pediatric cases with PCL, diagnosed at the Institute of Dermatology, Chinese Academy of Medical Sciences, from January 2010 to December 2021. RESULTS: Mycosis fungoides (MF), accounting for 41.6% of the total cases, was the most common subtype in pediatric PCL, and the hypopigmented MF accounted for 47.6% of all the MF cases. Lymphomatoid papulosis and chronic active Epstein-Barr virus infection tied for second place with a proportion of 22.8%. Primary cutaneous anaplastic large cell lymphoma, subcutaneous panniculitis-like T-cell lymphoma, primary cutaneous peripheral T-cell lymphoma, rare subtypes and primary cutaneous B-cell lymphoma, respectively, accounted for 2.0%, 4.0%, 4.0%, and 3.0%. Most patients had favorable prognosis during the follow-up. CONCLUSION: The study suggested that MF was the most common subtype in pediatric PCL in China, and most types of pediatric PCL had favorable prognosis.

Paediatric Mycosis Fungoides: Clinical Variants, Treatment Modalities and Response to Therapy.

Mycosis fungoides is a rare cutaneous lymphoma in the paediatric population. The aim of this study was to examine the epidemiological, clinical, and histological characteristics, as well as the treatment modalities and response to therapy of paediatric patients with mycosis fungoides. This retrospective cohort study reviewed the records of 37 paediatric patients treated at Rambam Medical Center, Israel, between 2013 and 2021. Extracted data included epidemiology, clinical presentation, histological reports, infiltrate clonality status, treatment modalities and response to therapy. The mean follow-up period was 60 months. All patients were diagnosed with stage IA or IB disease. Folliculotropic mycosis fungoides was the most prevalent variant (49%). Most patients were treated with phototherapy (90%), with a response rate of 85%, and a complete response rate of 55% after the first course. There were no significant differences in response to phototherapy between the folliculotropic or other variants (p = 0.072). Similarly, delayed diagnosis, atopic diathesis, clonality, phototherapy type or number of treatments, were not associated with response to therapy, while protracted phototherapy was associated with prolonged remission. In conclusion, mycosis fungoides in the paediatric population is an indolent disease with a favourable prognosis and potentially prolonged response to phototherapy.