A keratoancanthoma occurs when cells in a hair follicle do not grow normally. The growth may be triggered by a minor skin injury in an area that previously had suffered sun damage. Ultraviolet radiation from sun exposure is the biggest risk factor in keratoacanthomas.
A keratoacanthoma usually will appear on sun-damaged skin as a thick growth that has a central crusted plug.
Keratoacanthomas appear most often in people who are over the age of 60 and they are considered a low-grade skin cancer.