ABS1034 CUTANEOUS INVOLVEMENT IN ADULT HISTIOCYTOSIS

Résumé fourni par la source

Background: Histiocytoses are clonal diseases characterized by CD68+ histiocyte infiltration harboring somatic activation of the MAP-kinase pathway [1]. Clinical presentations vary depending on disease extent and aggressiveness, influenced by mutational status, particularly the BRAF V600E mutation [2]. Skin lesions are described in several histiocytosis subtypes, including Langerhans cell histiocytosis (LCH), Erdheim-Chester disease (ECD), Rosai-Dorfman disease (RDD), indeterminate cell histiocytosis (ICH), and juvenile xanthogranuloma (JXG). However, these lesions have primarily been reported individually. Objectives: This study aims to describe the epidemiology, clinical characteristics, and molecular features of skin lesions in a cohort of adults with histiocytosis. Methods: Data were retrieved from adult patients with histiocytosis followed at Dijon University Hospital from 2014 to 2024. Patient characteristics were compared based on the presence of cutaneous involvement. Results: Among 45 adult patients (17 LCH, 14 ECD, 6 RDD, 3 mixed ECD/LCH, 3 ICH, and 2 JXG), 17 (38%) had cutaneous involvement, with a higher prevalence among females (n=10). Patients with skin lesions were older at disease onset (mean age: 68 years, IQR 49–76) compared to those without (53 years, IQR 26–67; p=0.05). Cutaneous involvement was more common in ICH (3/17 vs. 0/28; p=0.04) and less frequent in ECD (2/17 vs. 12/28; p=0.04). Patients with skin lesions had more limited disease involvement (mean organs affected: 1.47 vs. 2.42; p=0.0365), particularly with fewer bone (7/17 vs. 22/28; p=0.02) and peri-renal (0/17 vs. 11/28; p=0.01) lesions. Mutational analysis showed a trend toward a higher prevalence of BRAF exon 12 deletion in patients with skin lesions (3/17 vs. 0/28; p=0.06). Further analysis of patients with cutaneous lesions (n=17) revealed no significant differences in elementary dermatologic lesions or mutational status. However, patients with unicentric skin lesions more frequently exhibited trunk (3/7 vs. 3/10; p=0.0498) and neck (5/7 vs. 0/10; p=0.00034) involvement. The presence of cutaneous involvement had no impact on relapse rates or overall survival. Multiple regression analysis showed a negative correlation between skin involvement and ECD (OR: -3.733, 95% CI [-7.38 to -1.28]; p=0.01). Conclusion: Cutaneous lesions are common in adults with histiocytosis, predominantly affecting older patients with limited disease. These lesions are often localized to the neck and trunk but remain rare among ECD patients. REFERENCES: [1] Emile J-F, Cohen-Aubart F, Collin M, et al. Histiocytosis. Lancet [Epub ahead of print] . [2] Héritier S, Emile J-F, Barkaoui M-A, et al. BRAF Mutation Correlates With High-Risk Langerhans Cell Histiocytosis and Increased Resistance to First-Line Therapy. J Clin Oncol 2016;34(25):3023–3030 . Acknowledgements: NIL . Disclosure of Interests: None declared . © The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Neither EULAR nor the publisher make any representation as to the accuracy of the content. The authors are solely responsible for the content in their abstract including accuracy of the facts, statements, results, conclusion, citing resources etc.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.