Caption

Seborrheic keratosis. Close-up of a seborrheic keratosis (seborrheic or senile wart) on the scalp of an 81-year-old male patient. This skin growth is caused by over-production of keratin, the tough fibrous protein found in hair and the outer layer of skin. Keratoses range from flat, dark brown rough patches to small, wart-like protrusions covered with a greasy, removable crust. They are mainly found on the trunk and usually occur in elderly patients. They are harmless, but as they are unsightly can be removed by cryosurgery (destruction of tissue using extreme cold) or surgical excision.