Large<unk>  nevi are caused by a mutation in the body's cells that occurs early in embryonic development, usually within the first twelve weeks of pregnancy. Mutations are sometimes found in genes that code for NRAS and KRAS proteins. There is no known method of prevention.
Congenital melanocytic nevus
Connective tissue nevus
Eccrine nevus
Benign melanocytic nevus
Adenoma sebaceum
Melanocytic nevus
Linear verrucous epidermal nevus
Pigmented spindle cell nevus