Pityriasis Lichenoides : Anatomo-clinical Aspects and Follow-up

Study Overview
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Brief Summary
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Introduction: Pityriasis lichenoides (PL) is an inflammatory dermatitis of undetermined origin consisting of specific papular lesions reflecting an indolent lymphoproliferative state. The current classification is confusing because it mixes semiological and chronological notions. The objectives of this study are to better describe the clinical, epidemiological, histological, phenotypic and evolutionary aspects of PL in an adult population. Methods: Investigators will perform a retrospective cohort study including patients with clinical and histological diagnosis of PL from the coding of the Department of Pathology of Henri-Mondor Hospital and from medical records and photographs of lesions if available, between January 2012 and August 2018. A follow-up telephone interviews will also be proposed to each patient to collect evolution data. Photographs will be systematically reviewed as well as cutaneous samples and a genomic analysis will be performed. Conclusion: Investigators would like to better understand clinical, histological features and evolutionary aspects of PL in an adult population.

Official Title
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Pityriasis Lichenoides: Anatomo-clinical Aspects and Follow-up Monocentric Retrospective Study

Conditions
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Pityriasis Lichenoides

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥ 18 years Patients with Pityriasis Lichenoides selected from histological coding OT0431, seen at Henri Mondor and with a diagnosis verified from medical records. Exclusion Criteria: Histological coding error Histological records of patients in care outside Henri Mondor (cases referred for histological expertise only but not seen clinically) Clinical lesions incompatible with Pityriasis Lichenoides according to classically published semiological data Missing or insufficient medical records for data exploitation

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To study clinical Aspects of Pityriasis Lichenoides on a large series of adult patients | Epidemiological and and clinical aspect description of the lesions from medical charts and photographs: age, sex, suspected trigger of the disease, past medical history, frequency of necrotic lesions, topography of lesions, fever, altered general conditions, treatment modalities of the flare. | It will be measured within 6 months of enrollment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To study histological features of Pityriasis Lichenoides | The histological description will make use of a centralized re-reading of the slides according to a standardized grid (appearance of the epidermis, type and topography of the dermal infiltrate, results of the immunolabelings etc ...). The investigators aim to investigate the frequency of patients with patterns of pityriasis lichenoides mimicking lymphomatoid papulosis or mycosis fungoides and to correlate the histological aspect with clinical lesions. | It will be measured within 6 months of enrollment | 
| To study molecular features of Pityriasis Lichenoides | number of clone T in the skin and in the blood. | It will be measured within 6 months of enrollment | 
| To study the treatment during patients' monitoring | number of patients with need of a prolonged treatment | It will be measured within 6 months of enrollment | 
| To study the duration of outbreak during patients' monitoring | the time to healing | It will be measured within 6 months of enrollment | 
| To study the relapse during patients' monitoring | the number of relapses | It will be measured within 6 months of enrollment | 
| To study the number of outbreaks during patients' monitoring | the number of outbreaks | It will be measured within 6 months of enrollment | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Pityriasis Lichenoides;, cutaneous lymphoma, lymphoproliferation