Pityriasis Lichenoides : Anatomo-clinical Aspects and Follow-up

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

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.

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