Patient with Gorlin Syndrome and type 2 mosaicism successfully treated with sonidegib

Background: Basal Cell Carcinoma (BCC) represents a common neoplasm affecting sun-exposed sites, while it rarely arises in genital areas.The surgical excision with adequate margins is the preferred option for the curative treatment of BCC, despite it is difficultly obtained in the locally advanced lesions (laBCCs).To date, only sporadic cases of genital laBCC have been treated with Hedgehog Pathway inhibitors (HPi).Methods: An 83-year-old female was admitted to the Dermatology Department in February 2024, complaining of three large and ulcerated lesions located on the vulva and the mucosal surface of the left major labia since unprecise time.She was aware of the ulcer when it started bleeding, a few weeks before consultation.Subsequently she underwent to skin biopsies taken from the pubic and the major labia areas, that confirmed the diagnosis of BCC.Results: Given the wide size of the ulcers, that were present in multiple lesions, together with the peculiarity of the involved mucosal site, systemic therapy with HPI (Sonidegib 200 mg/day) was started in March 2024.After one month the patient complained of dysgeusia, muscle cramps and dizziness related to the oral therapy.Due to such adverse effects, the reduced schedule (Sonidegib 200 mg every other day) was decided, leading to the rapid resolution, while the ulcers continued to improve with rapid reduction in their wideness and reepithelization.After 4 months the ulcers were completely recovered.Blood tests were in the normal range.The patient was suggested to continue the therapy for further 6 months to obtain a complete and persistent healing, and she is currently in follow up.Conclusions: We present here a case of vulvar laBCC successfully treated with reduced schedule HPi, leading to a rapid and complete response, and counteracting the most common side effects.In comparison with the existing literature 1 , our case highlights a fast and persistent response obtained with reduced dosage.1. Camela E, Villani A, Scalvenzi M, Costa C. Giant basal cell carcinoma of the vulva successfully treated with Sonidegib.Dermatol Ther 2022;