Keratoacanthomas are thought to be a type of squamous cell skin cancer.  They typically have a crater-like appearance with a slightly elevated lesion and a thick crust. Keratoacanthomas often have a thick layer of scale. Typical to keratoacanthomas, this lesion is red and inflamed at the base. This image displays a cup-like shape with a thick "plug" of scaly skin typical of keratoacanthomas. This image displays a keratoacanthoma on an elbow. This image displays a close-up of a keratoacanthoma. This image displays a keratoacanthoma, a form of skin cancer, that needs a biopsy by a dermatologist and full removal. A keratoacanthoma appears on sun-damaged skin and typically has a red, firm base and central crust-like “plug.” This image displays a typical keratoacanthoma in front of the top of the ear. This image displays a lesion with a thick, scaly crust typical of keratoacanthoma. This image displays a keratoacanthoma on the lip. This image displays a keratoacanthoma.
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Keratoacanthoma  Information for adults

Picture of Keratoacanthoma: Keratoacanthomas are thought to be a type of squamous cell skin cancer.  They typically have a crater-like appearance with a slightly elevated lesion and a thick crust. Divider line
Keratoacanthomas are thought to be a type of squamous cell skin cancer. They typically have a crater-like appearance with a slightly elevated lesion and a thick crust.
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Signs and Symptoms
The most common locations for keratoacanthoma include:
  • Center of the face
  • Backs of hands
  • Forearms
  • Ears
  • Scalp
  • Lower legs, especially in women
A keratoacanthoma appears and grows rapidly over the course of 2–6 weeks. Starting as a small, pimple-like lesion, a keratoacanthoma typically develops into a dome-shaped, skin-colored nodule with a central depression filled with keratin (the major protein found in hair, skin, and nails). Keratoacanthoma usually range in size from 1–2.5 cm.

In rare cases, multiple keratoacanthomas may develop as part of a larger group of symptoms (syndrome).

Most keratoacanthoma are painless, though some may be itchy. Depending on the site of involvement, keratoacanthoma may interfere with normal function of the affected area.
Last Modified: 22 Dec 2008