Eruptive squamous cell carcinomas after vemurafenib therapy.

Background: Vemurafenib is an oral BRAF inhibitor recently approved for the treatment of metastatic melanoma. Patients treated with this medication have been reported to have the occurrence of squamous cell carcinoma (SCC) and/or actinic keratosis (AK).

Objective: We report the case of a patient treated with vemurafenib for papillary thyroid carcinoma who subsequently developed multiple SCCs and AK of the skin. The lesions were deemed related to the medication and treated with excision. In addition, subsequent development of SCCs and AK was successfully prevented with a combination of isotretinoin and 5-fluorouracil in this patient. We discuss postulated mechanisms for these findings, as well as potential preventive therapy with the aforementioned combination regimen in patients undergoing treatment with vemurafenib.