Keratoacanthoma: Causes, Symptoms, Diagnosis, Treatment and Risk Factors

It is an epithelial tumor of skin cancer, benign common of pilosebaceous origin, pink with a dome shape that has a central protein crater like keratin.

This disease is characterized by rapid evolution, usually has a spontaneous resolution, occurs in the hair follicles of the skin and rarely spreads to other cells.

It occurs more frequently in men over 55 years of fair skin.

It is more common in those people who have a higher degree of exposure to the sun and are usually shown on the face, back of the hands and arms.

Commonly, it is not associated with internal malignancies, except in those cases of very low incidence, in which keratoacanthomas are associated with a disease called Muir-Torre syndrome , which are related to malignant internal neoplasms.

The keratoacanthoma presents a rapid growth in the skin, it expands from 1 to 2 mm to 1 to 3 cm in a few days, these usually stop growing around 6 to 8 weeks.

But they remain inactive and intact for a period of 2 to 6 weeks and finally involute slowly and spontaneously.

Although keratoacanthomas are benign tumors of spontaneous regression, it is not always possible to distinguish them from squamous cell carcinomas because they have epidemiological characteristics and develop at similar rates, in addition to having common causes.


The exact cause of keratoacanthoma is still unknown, but there are some factors that can favor them as:

  • Sun exposure.
  • Contact with some chemicals that can cause cancer.
  • Smoking
  • Contamination with virus strains, such as human papilloma .
  • Previous traumas
  • Genetic type factors.


  • The symptoms of keratoacanthoma are visual and persist for two to three months.
  • Appearance is often compared to a small volcano.
  • The keratoacanthoma, emerge as a small and rounded papule.
  • Then, the lesion grows reaching a size between 1 to 2 centimeters in a few weeks.
  • The wound resembles a dome with a plug in the center of brown keratin.
  • Once the wound is healed, it flattens leaving a scar.


It is possible to diagnose a keratoacanthoma just by looking at it, but because of the close resemblance to squamous cell carcinoma, which is an invasive type of skin cancer, it is recommended to perform a tissue biopsy.

This biopsy is done by taking enough tissue from the lesion with the help of a scalpel.

The sample is analyzed and evaluated to form a diagnosis.


The keratoacanthoma will disappear on its own, but this lesion remains for many months on the skin.

Therefore, surgery or administration of drugs for its elimination is recommended

The options for elimination treatments will depend on the location of the injury, the patient’s health history and the dimensions of the injury.

The most frequently used treatment is the practice of minor surgery, with the administration of local anesthesia, for the surgical excision of the tumor.

Other treatments include:

  • Electrodesiccation and curettage.
  • The microscopic surgery of Mohs, where small pieces of the skin are removed until the lesion is completely eliminated. This treatment is most often used when the keratoacanthoma appears in the ears, nose, hands and lips.

Drug treatments are recommended with which the size and number of lesions are reduced, helping to make elimination treatments or surgeries less invasive.

These do not represent a substitution for surgery or other treatments for elimination. Among these medications we have:

  • The application of a topical cream of 5-fluorouracil, three times a day for 1 to 6 weeks.
  • Administer 5-fluorouracil injections. This technique is used when large, rapidly growing keratoacanthomas appear.
  • The use of podophyllin resin, intralesional injections of methotrexate and radiotherapy are highly recommended in giant keratoacanthomas.
  • The administration of isotretinoin and acitretin orally have been useful in patients with multiple keratoacanthomas.

In general, the prognosis for a keratoacanthoma is good, since it is a benign tumor.

Risk factor’s

The risk factors of keratoacanthoma are:

  • Age, developing a keratoacanthoma before age 20 is very rare, usually appear in people over 60 years.
  • Long exposures to the sun or ultraviolet rays (tanning beds).
  • Own a white skin.
  • Have compromised immune systems.
  • Sex, there is a greater risk in men than women.
  • The genetic predisposition, people with direct relatives who have suffered from some type of skin cancer have a higher risk of developing multiple keratoacanthomas.
  • Having suffered from skin cancer, studies have reported the spontaneous growth of keratoacanthoma two or three months after undergoing surgeries to treat skin cancer.

Once you have suffered from a keratoacanthoma, it is very common to reappear, so it is advisable to go regularly to the doctor to follow up.

It is also important to adopt healthy habits to protect your skin and prevent recurring injuries.