Small nodules that grow slowly on the surface of the skin are known as Keratoacanthomas. They have a hard and scaly centre which is filled with Keratin, a protein. The skin lesion resembles a volcanic crater with a sprouting center. It is considered a skin tumour, but is not malignant.
Keratoacanthomas are considered an epithelial neoplasm. They are found on the outer layer of the skin, which is called the epidermis. In most cases, the area of the skin which is most exposed to the sun and tends to get damaged, is vulnerable to the presence of this skin lesion. Certain amount of damage to the DNA of the skin makes it more likely for Keratoacanthomas to grow.
It closely resembles Squamous Cell Carcinoma (SCC) which is a rapidly advancing and malignant cancer. This is a condition, which if left untreated can prove to be devastating for the patient. For this reason, it is important to get a timely diagnosis to confirm that the Keratoacanthoma is not Squamous Cell Carcinoma.
How is Keratoacanthoma Diagnosed?
The doctor will begin with a physical examination of the skin lesion and evaluate the medical history of the patient. Although Keratoacanthoma is not genetic, a person who has previously developed the condition may be prone to the skin lesions forming again. The general physician is likely to refer the patient to a dermatologist, who will conduct a dermoscopy. This will allow the dermatologist to use a non-invasive technique to gain more information about the skin lesion.
The change in skin pigmentation can also be studied using Wood’s lamp examination. Here, the doctor will examine the skin using a lamp of ultraviolet light. It gives the dermatologist a more detailed view of the skin. Should the skin lesions seem too much like the SCC, the dermatologist will recommend a biopsy of the affected tissue to confirm the possibility.
A biopsy is conducted by removing the skin lesion and sending it to a laboratory. There a pathologist will study it under a microscope. A biopsy is considered the gold standard to diagnose this skin condition. Using the clinical findings, the microscope findings and a study of the affected tissue the pathologist will give a definite diagnosis. Since a number of skin conditions have similar symptoms, additional tests may be suggested to the patient.
Treatment Options for Keratoacanthoma
Removal of the skin lesion, which occurs during a biopsy, is considered complete treatment as long as no part of the affected tissue is left behind. In most cases Keratoacanthoma will experience spontaneous healing after a few months even if no biopsy is conducted. Topical creams like 5-fluorouracil have also helped. The condition will leave behind a scar on the skin even once the lesion has disappeared.
Curettage and Cautery
This form of treatment involves the removal of the abnormal growth of tissue using a small, sharp-edged instrument called a curette. The action is performed under local anaesthesia. The raw area revealed is then cauterized. This involves heating the area with an implement so that the bleeding stops and to prevent infection.
This involves freezing the epidermal neoplasm with liquid nitrogen. The area of the affected tissue is dabbed with a cotton tipped applicator. The cotton is soaked in liquid nitrogen and will feel extremely cool to the skin, which is followed by a slight burning sensation. The skin lesion will literally fall off when this treatment is used. It is quite safe and the procedure is not very expensive.
Normally Keratoacanthomas are not treated with radiation. Chemotherapy is usually reserved for skin cancers that are malignant and of a more aggressive nature. However, if there are multiple Keratoacanthomas, the dermatologist may suggest radiation therapy to the patient to avoid multiple cuts on the skin as would happen with curettage and cautery. It will be a mild dose of radiation and will have to specific to the skin lesion type.
Self-Care for Keratoacanthoma
Should you have a job or hobby that makes you spend many hours outdoors, it is recommended to take care of your skin to prevent damage. Use a broad-spectrum sunscreen with a Sun Protection Factor or SPF of at least 30. That way exposed areas of your skin are protected from ultraviolet radiation and possible damage to skin DNA. As this is the primary factor that causes Keratoacanthomas, avoiding UVA and UVB radiation should be a priority.
If you have developed a Keratoacanthoma once before, ensure that you regularly examine your skin for lumps and lesions. Avoid getting sun burns and ensure that you wear full sleeves when out in the sun, in addition to the sunscreen. A wide rimmed hat also works well as a sun protector. Reduce the time out in the sun by taking regular indoor breaks. Ensure that your immune system is boosted with good diet and regular exercise as immunosuppression is also a factor for development of Keratoacanthomas.
Reviewed by Afsaneh Khetrapal Bsc (Hons)