Keratoacanthoma:
Information for adults

If left untreated, most keratoacanthoma spontaneously disappear (resolve) within 6 months, leaving a depressed scar. However, they may cause significant damage to the skin and underlying layers of tissue as well as psychological distress. Additionally, rare forms of keratoacanthoma may spread (invade) aggressively below the skin level and into the lymph glands, and your doctor has no way to tell this type from the more common form. Therefore, prompt diagnosis and treatment are recommended.

If your physician suspects a keratoacanthoma, he or she will first want to establish the correct diagnosis by performing a biopsy. The procedure involves:

1. Numbing the skin with an injectable anesthetic.
2. Sampling a small piece of skin by using a flexible razor blade, a scalpel, or a tiny cookie cutter (called a "punch biopsy"). If a punch biopsy is taken, a stitch (suture) or 2 may be placed and will need to be removed 6–14 days later.
3. Having the skin sample examined under the microscope by a specially trained physician (dermatopathologist).

Once the diagnosis of keratoacanthoma is established, the treatment options usually include:

• Freezing with liquid nitrogen (cryosurgery), in which very cold liquid nitrogen is sprayed on the keratoacanthoma, freezing it and destroying it in the process.
• Electrodesiccation and curettage, also known as "scrape and burn." After numbing the lesion, the doctor uses a sharp instrument (curette) to "scrape" the skin cancer cells away, followed by an electric needle to "burn" (cauterize) the tissue. The electrodesiccation helps to kill the cancer cells and also to stop any bleeding at the site.
• Removal (excision), in which the doctor uses a knife-like instrument (scalpel) to cut out the keratoacanthoma and then place stitches to bring the wound edges together.
• Mohs micrographic surgery, in which the physician takes tiny slivers of skin from the cancer site until it is completely removed. This technique is particularly useful for keratoacanthoma located on the nose, the ears, the lips, and the hands.
• Radiation treatment, where X-ray therapy is often useful for patients who might have difficulty with a surgical procedure because of other health issues.

Very rarely, keratoacanthoma are treated with medicine injected directly into the skin lesion (intralesional chemotherapy). In patients with more than one keratoacanthoma, the doctor may suggest taking a pill (isotretinoin) to reduce their size and number.

Finally, it is important to remember that treatment of keratoacanthoma is not complete once the skin cancer has been removed. Frequent follow-up appointments with a dermatologist or with a physician trained to examine the skin are essential to ensure that the keratoacanthoma has not returned and that a new skin cancer has not developed somewhere else on your body. In addition, good sun protection habits (see the above Self-Care section) are vital to preventing further damage from UV light.