Keratoacanthomas are round, firm, usually flesh-colored or slightly reddish growths that have a central crater that is scaly or crusted.

Keratoacanthomas appear most commonly on the face, forearm, and back of the hand and grow quickly. In 1 or 2 months, they can grow into lumps up to 1 inch (about 2.5 centimeters) wide, after which they usually begin to shrink. They usually disappear within 6 months, often leaving a scar.

Most doctors consider keratoacanthomas to be a form of squamous cell carcinoma, a type of skin cancer (Skin Cancers: Squamous Cell Carcinoma). Therefore, doctors often recommend they be treated after performing a biopsy, in which a piece of skin is removed and examined under a microscope. Keratoacanthomas are usually cut out or scraped (curetted).

Last full review/revision September 2008 by Daniel W. Collison, MD