AID Expression in Vulvar SCC Arising From Lichen Sclerosus et Atrophicus: A Retrospective Study.

Lichen sclerosus et atrophicus (LSA) is a chronic, progressive inflammatory disorder with a risk of malignant transformation to squamous cell carcinoma (SCC). This study investigated the role of activation-induced cytidine deaminase (AID) in UV-independent SCC arising from LSA. We retrospectively analyzed 19 female patients, including 5 SCC cases. AID expression was significantly associated with SCC development, pruritus, and shorter disease duration. AID was detected in SCC lesions and adjacent LSA tissues, mainly in basal cells. Reduced AID expression was observed in higher-stage tumors, suggesting its potential as a prognostic indicator. The use of topical corticosteroids was less common in AID-positive patients, suggesting a possible association. These findings suggest a possible inverse association between topical corticosteroid use and AID expression.