PIK3CA and seborrheic keratosis: By analogy, somatic mutations in oncogenic fibroblast growth factor receptor 3 (FGFR3) or phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) result in seborrheic keratosis (senile wart) [4] or epidermal nevi [162].