Keratoacanthomas are round, firm, usually flesh-colored growths that have a central crater that is scaly or crusted. Some keratoacanthomas may be a form of squamous cell carcinoma.
Keratoacanthomas appear most commonly on sun-exposed areas, such as the face, forearms, and back of the hands, and grow quickly. In 1 or 2 months, they typically grow into lumps about 1 inch (about 2.5 centimeters) wide, but sometimes they grow over twice as large. They may spontaneously disappear within a few months, often leaving a scar.
The cause of keratoacanthomas is unknown. Most doctors consider keratoacanthomas to be a form of squamous cell carcinoma, a type of skin cancer.
Diagnosis of Keratoacanthomas
Biopsy
To confirm the diagnosis of keratoacanthoma, doctors often do a biopsy, in which a piece of skin is removed and examined under a microscope. Sometimes they completely remove the tumor during the biopsy.
Treatment of Keratoacanthomas
Surgery or injections of methotrexate or 5-fluorouracil
Prevention of Keratoacanthomas
Because keratoacanthomas may be caused by exposure to sun, people can help prevent this cancer by doing the following, starting in early childhood:
Avoiding the sun: For example, seeking shade, minimizing outdoor activities between 10 AM and 4 PM (when the sun’s rays are strongest), and avoiding sunbathing and the use of tanning beds
Wearing protective clothing: For example, long-sleeved shirts, pants, and broad-brimmed hats
Using sunscreen: At least sun protection factor (SPF) 30 with UVA and UVB protection used as directed and reapplied every 2 hours and after swimming or sweating but not used to prolong sun exposure
More Information
The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
American Cancer Society: What Are Basal and Squamous Cell Skin Cancers? Information about squamous cell carcinoma, including treatment options and prognosis
