Histopathology-Paired Clinical Improvement Following Topical Rosa damascena-Derived Exosomes in Long-Standing Refractory Male Genital Lichen Planus: A Single-Patient Case Report.

Lichen planus (LP) is a chronic T-cell-mediated interface dermatitis. Genital involvement is frequently refractory to topical corticosteroids and calcineurin inhibitors and may lead to fibrosis, architectural distortion, and substantial impairment in quality of life. We report the case of a 39-year-old male with a 15-year history of biopsy-confirmed genital LP unresponsive to high-potency topical corticosteroids and tacrolimus 0.1%, who received topical Rosa damascena stem cell-derived exosomes (RSCEs) at biweekly sessions for four months. Each session combined 2 mL of in-office application with superficial microneedling in hyperkeratotic areas, followed by 3 mL of the same-day home application. No concomitant topical corticosteroid or calcineurin inhibitor was used during the treatment period. Paired pre- and post-treatment 4 mm punch biopsies were obtained from the same anatomical region, processed using identical protocols, stained with hematoxylin and eosin, and reviewed by a board-certified dermatopathologist. After four months, we observed clinical resolution of pruritus and fissuring, progressive desquamation of hyperkeratotic plaques, and improved tissue elasticity. The post-treatment biopsy showed reduced hyperkeratosis and hypergranulosis, attenuation of the band-like lymphohistiocytic infiltrate, partial restoration of the dermoepidermal interface, and reduced basal vacuolar degeneration relative to baseline. No dysplastic changes or treatment-related adverse events were observed. These observations are based on a single uncontrolled case and cannot establish causality, isolate the contribution of microneedling, or demonstrate disease modification beyond the descriptive level. Histological assessment was qualitative; no semi-quantitative or immunohistochemical analysis was performed. The exosome preparation was used as a standardized commercial product and was not independently characterized in our laboratory. The findings are intended solely as hypothesis-generating. Independent characterization of the exosome preparation, immunohistochemical and ideally transcriptomic profiling of paired tissue, and prospective controlled studies are required before any therapeutic claim can be supported.