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Gregory L. Wells

, MD, Ada West Dermatology and Dermatopathology

Last full review/revision Jan 2021| Content last modified Jan 2021
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Keratoacanthomas appear most commonly on sun-exposed areas, 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.

Diagnosis of Keratoacanthomas

  • Biopsy

To confirm the diagnosis of keratoacanthoma, doctors often do a biopsy Biopsy Doctors can identify many skin disorders simply by looking at the skin. A full skin examination includes examination of the scalp, nails, and mucous membranes. Sometimes the doctor uses a hand-held... read more Biopsy , in which a piece of skin is removed and examined under a microscope. Sometimes they completely remove the tumor during the biopsy.

Prevention of Keratoacanthomas

Because keratoacanthomas can be caused by exposure to sun, people can help prevent this cancer by doing the following:

Treatment of Keratoacanthomas

  • Surgery or injections of methotrexate or 5-fluorouracil

There is no guarantee that a keratoacanthoma will spontaneously disappear, and even when they do disappear, there is often a scar. Thus, keratoacanthomas are usually cut out or scraped (curetted) or injected with methotrexate or 5-fluorouracil.

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