Vemurafenib-induced neutrophilic panniculitis.

Vemurafenib is a targeted therapy, used in patients with metastatic cutaneous melanoma who carry the BRAF V600E mutation, with a relative reduction of 63% in the risk of death. Several adverse events have been described previously, such as photosensitivity or squamous-cell carcinomas. Two cases of panniculitis have been reported recently with two different selective BRAF inhibitors. We report two cases of neutrophilic panniculitis in patients treated by vemurafenib for a metastatic melanoma. Clinical and biological examinations showed no indications for an immune nor an infectious cause of neutrophilic panniculitis. Thus, we believe that vemurafenib caused this panniculitis. Treatment with vemurafenib was maintained in both patients because of the clinical and radiological tumoral responses. One patient showed spontaneous recovery, whereas the other patient presented several recurrences of panniculitis. We believe that physicians should be aware of this cutaneous side effect of vemurafenib, but it should not lead to discontinuation of this treatment.