Cutaneous manifestations of vemurafenib therapy for metastatic melanoma

Vemurafenib, a BRAF inhibitor, is FDA-approved for the treatment of metastatic melanoma in patients who harbor the BRAF V600E mutation. By inhibiting BRAF, vemurafenib prevents the mitogen-activated protein kinase (MAPK) pathway from driving melanoma growth. Here we present a patient with paradoxical activation of the MAPK pathway by vemurafenib, ultimately resulting in deleterious cutaneous manifestations. An emphasis on close follow-up is warranted for new or changing lesions for patients on this medication and other BRAF inhibitors.