Cutaneous adverse event associated with vemurafenib in a 3-year-old pediatric patient with BRAF mutation-positive metastatic melanoma and factor X deficiency.

Malignant melanoma is very rare in childhood. The approach to diagnosis and treatment in children has been adopted from adult guidelines. Vemurafenib is indicated in adults with BRAF V600 mutation-positive stage IIIc/IV melanoma and causes cutaneous adverse events. We report on a 3-year-old child with recurrent, metastatic (bone) BRAF mutation-positive melanoma. He also had severe factor X deficiency. Four days after vemurafenib treatment, bilateral palpebral edema and violet-colored hyperpigmentation were observed. There was no objective response to vemurafenib; however, bone pain regressed slightly. Our patient is the youngest patient who received vemurafenib for BRAF V600 mutation-positive metastatic melanoma in the literature.