Keratoacanthoma is a type of skin cancer that emerges as a large bump with an open, mineral-filled crater in the middle. Bumps can appear on the head, arms, legs, or torso. It is uncommon for a person to have more than one keratoacanthoma tumor on his or her body, and this type of cancer almost never spreads to other parts of the body. A dermatologist can usually remove a lesion with a quick and relatively simple surgical procedure.
Doctors and medical researchers are unsure of the exact causes of keratoacanthoma, but they have identified several risk factors for developing the condition. Overexposure to sunlight is considered a probable cause since most lesions appear on areas of skin that are frequently exposed to light, especially the face and arms. Some studies have shown that working around hazardous industrial chemicals is highly correlated with skin cancer. In addition, human papillomavirus infection and direct trauma to the skin have also been identified by researchers as potential causes of keratoacanthoma. People over the age of 50 are most susceptible to the cancer, and it is very rare in patients under the age of 20.
A keratoacanthoma lesion first appears as a small red or skin-colored bump. Over the course of two to four weeks, it can grow into a volcano-like mound with a large, keratin-filled opening. Active lesions are usually less than two inches (about 5 cm) in diameter and have a hard, crusty, white appearance. After about six weeks, a lesion begins to slowly shrivel and shrink for about a year until a hard, disfiguring scar is left.
An individual should visit a dermatologist or primary care physician if he or she notices an abnormal skin growth. A doctor can collect a tissue sample from within the lesion that can be analyzed by laboratory scientists. Extensive lab tests must be conducted to differentiate keratoacanthoma from another more dangerous condition called squamous cell carcinoma. Once a diagnosis has been made, the doctor can determine the best course of treatment based on the size and location of the tumor.
A surgeon usually chooses to remove a small- or medium-sized lesion by applying a local anesthetic to numb the area and cutting out the tumor. The wound is sutured and a patient is given antibiotics to help prevent infection. In the case of a large lesion that cannot easily be removed by surgery, a patient may need to undergo radiation treatments to ablate it. Following a successful procedure, a patient is typically instructed to wear sunscreen and schedule regular dermatological checkups to help prevent future skin problems.