Keratoacanthoma (KA) is a low-grade skin cancer tumor that is similar to squamous cell carcinoma (SCC).

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What Is Keratoacanthoma?

Keratoacanthoma (KA) is a low-grade skin cancer tumor that is similar to squamous cell carcinoma (SCC). It originates in the skin’s pilosebaceous glands, or hair follicles.

This skin cancer tumor grows rapidly, in just a few weeks to a few months. It rarely develops into invasive or metastatic carcinoma, which means it rarely spreads. Many doctors pursue aggressive surgery to treat patients with KA, so most tumors are quickly removed once they are detected.

What Causes Keratoacanthoma?

Exposure to sun and chemical carcinogens may cause keratoacanthoma tumors. Additionally, KA can be caused by trauma, human papillomavirus (HPV), and genetic factors. Sometimes the cause of KA is not known.

KA and squamous cell carcinoma consist of very similar epidemiological features. This suggests they are both caused by exposure to natural sunlight.

Who Is at Risk for Keratoacanthoma?

People who have had prolonged exposure to sunlight are at a higher risk for keratoacanthoma. People who frequently use tanning beds are also at risk. Developing KA before the age of 20 is rare. People with compromised immune systems may be more at risk. People over the age of 60 are more at risk.

What Are the Symptoms of Keratoacanthoma?

Keratoacanthoma shows up as a lesion or growth on the skin that reaches a size of between one and two centimeters within a few weeks. It then grows more slowly. In rare cases, KA may show up as multiple tumors that can be five centimeters to 15 centimeters in size. It is a non-melanoma skin cancer that rarely metastasizes, or spreads to other areas of the body, but it can still be dangerous and should be treated by a physician.

If you notice a changing or growing colored patch on your skin, contact a doctor or dermatologist.

How Is Keratoacanthoma Diagnosed?

Most doctors take a biopsy of the lesion instead of shaving off skin cells. The sample is then evaluated to form a diagnosis.

How Is Keratoacanthoma Treated?

This condition is commonly treated by performing a minor surgery that removes the tumor.


Though the primary treatment for KA is surgery, doctors can prescribe systemic retinoid drugs (such as isotretinoin) for patients who have numerous lesions. Intralesional methotrexate 5-fluorouracil, bleomycin, and steroids have been used in patients that are not good candidates for surgery.

Home Care

Home care involves treating the site of the tumor after it is removed to help the skin in the area heal.

Alternative Therapies

Radiation therapy, laser therapy, and cryotherapy have also been used to treat KA.

What Is the Outlook for Keratoacanthoma?

People who develop KA are at a higher risk for future episodes. If you have had a KA tumor or lesion, schedule regular visits with your doctor, so you can quickly identify and treat KA growths at an early stage.

Preventing Keratoacanthoma

You can take steps to prevent KA. Protect yourself from sun exposure with clothing, hats, and sunscreen. Regularly examine your skin for new or growing moles or colored patches. Make regular appointments with doctor or dermatologist so he or she can detect and promptly remove any KA tumors.

Written by: Kristen Fischer
Edited by:
Medically Reviewed by: George Krucik, MD, MBA
Published: Jan 13, 2014
Published By: Healthline Networks, Inc.
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