43 | LONGSTANDING GENERALIZED EXTRAGENITAL LICHEN SCLEROSUS WITH GENITAL INVOLVEMENT UNMASKED BY ACUTE INFLAMMATORY DERMATOSIS

V. Corti¹, L. Sanna¹, A. Magnatta¹, R. Daher¹, S. Landini¹, A. Verdelli², M. Caproni² | ¹Sezione di Dermatologia, Dipartimento di Scienze della salute, Università di Firenze, Italy; ²S.O.S. Immunopatologia cutanea e malattie rare dermatologiche, P.O. Piero Palagi, Azienda USL Toscana Centro, Dipartimento di Scienze della Salute Università degli Studi di Firenze, Italy

Lichen sclerosus (LS) is a chronic inflammatory dermatosis primarily affecting the anogenital region. LS may cause itching, soreness, dysuria and sexual dysfunction. Extragenital LS occurs in 15-20% in association with anogenital involvement, whereas isolated extragenital lesions are described in only 6% of patients. Extragenital LS most commonly affects the neck, shoulders, and upper trunk and may be pruritic. However, both genital and extragenital LS can be clinically subtle and remain unrecognized for years, leading to delayed diagnosis. In this report, we describe an unusual case of long-standing, diffuse extragenital and genital LS incidentally diagnosed during the evaluation of acute inflammatory nodular lesions of the legs. A 39-year-old woman presented with a three-month history of pruritic nodular lesions on the right pretibial area. Clinical examination, microbiological testing and histopathological evaluation of these lesions were performed. A comprehensive total-body skin examination revealed widespread hypopigmented macules, reportedly appearing after an episode of typhoid fever and stable over time, prompting an additional skin biopsy. The differential diagnosis included extragenital LS and vitiligo. Subsequent clinical follow-up, including evaluation for genital involvement, were carried out. Histopathological analysis of the nodular lesion demonstrated neutrophilic granulocytic dermatitis consistent with a reactive, infective process. The patient’s clinical course was complicated by erysipelas, which was successfully treated with amoxicillin/clavulanic acid. Histopathological examination of the hypopigmented macule revealed epidermal atrophy, dermal collagen homogenization and a band-like lymphocytic infiltrate, confirming the diagnosis of extragenital LS with an uncommon generalized distribution. Subsequent evaluation disclosed vulvar involvement consistent with genital LS. Systemic treatment with methotrexate combined with high-potency topical corticosteroids was initiated, with partial clinical improvement and good tolerability at initial follow-up. This case highlights the importance of a thorough total-body skin examination and a low threshold for histopathological confirmation, even in long-standing, asymptomatic lesions. In this patient, the occurrence of an acute inflammatory condition enabled the diagnosis of a previously unrecognized chronic dermatosis that might otherwise have remained overlooked.