Keratoacanthoma (KA)

Keratoacanthoma (KA) is a growth which is now thought to be a variant of squamous cell carcinoma and is generally treated as a malignant skin tumor. Unlike typical SCCs, keratoacanthomas grow relatively quickly and in the span of a few weeks can develop from a small pimple-like growth to the size of a nickel or larger. KAs tend to be dome-shaped, reddish or reddish-purple in color, and are sometimes described as resembling a volcano. There is a central indentation or crater which is usually filled with rough, keratin-type debris. They are more common in older individuals, and generally occur on sun-exposed or sun-damaged skin. Sun exposure is thought to be the primary risk factor, although other factors including exposure to radiation or to certain chemicals, immunosuppression (such as in HIV or by treatment for organ transplants), or trauma may be implicated in some cases. In rare instances, KAs can continue to grow over time, forming large, disfiguring lesions. The risk for developing keratoacanthomas is increased in individuals with hereditary genetic conditions such as Lynch syndrome (especially the Muir-Torre variant) and xeroderma pigmentosum.

All photographs and diagrams are intended for informational purposes only and are not intended to be used for diagnosis.  A dermatologist should be consulted for examination and diagnosis of skin lesions.

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