Keratoacanthoma is an abnormal growth on the surface of the skin. It is a small lesion which has a hard centre, filled with the protein Keratin. The little bump on the skin is flesh coloured and dome shaped. It usually originates in the hair follicle and is considered a subtype of well differentiated squamous cell carcinoma.

The skin condition of Keratoacanthoma is mostly found in adults who have been exposed to the sun’s ultraviolet radiation on a frequent basis. The epidermal neoplasms generally occur on the exposed portions of the face, the hands, arms, torso and legs. The skin damage caused by the sun’s rays are a factor in precipitating the condition.

Progress of Keratoacanthoma

The skin will develop a small bump of 1-2mm size initially. The flesh coloured bump will then begin to expand over the next 6 to 8 weeks. It will resemble a dome shape and have a central core of hard keratin that pushes against the skin, drawing it taut. Once it has grown to its maximum size of 1-3 cm the bump becomes dormant and does not change for nearly 2 to 6 weeks.

Even if no treatment is carried out, the bumps will begin to spontaneously heal within 2 to 12 months. The hard centre of keratin will fall out as the skin stretched tight over it will thin out and break. The sides of the bump, which will look like a volcanic crater, will regress gradually. Eventually the lesion will heal and flatten out completely. It will leave behind a scar at the location of the bump.

Diagnosis of Keratoacanthoma

Diagnosis of Keratoacanthoma is often difficult as it resembles numerous other skin conditions. The removal of the lesion is recommended as the bump on the skin could also be Squamous Cell Carcinoma. This is a much more aggressive form of skin tumour that can cause major disfigurement. Squamous Cell Carcinoma should not be left undetected.

As Keratoacanthoma closely resembles this more dangerous illness, a biopsy is advised to ensure that there is no other danger to the health of the patient. There are many regional variations in the diagnosis of Keratoacanthomas and Squamous Cell Carcinoma as it is difficult to differentiate them even at a microscopic level.

Treatment of Keratoacanthoma

The removal of the skin lesion is considered a complete treatment for Keratoacanthomas if the dermatologist successfully removes the entire affected tissue. This removal can be done via the following ways:

Excision

Cutting away of the Keratoacanthoma with a surgical instrument. The affected tissue is cut and the wound left behind is stitched up for aiding faster healing. Dressing of the surgical wound may need to be done at regular intervals till it has healed completely. It would normally take about a week for the wound to heal.

Curettage and Cautery

This is an electrosurgery procedure where the flesh coloured bump is first scraped off using a spoon like instrument known as a curettage. Following this, heat is applied to the area of the skin to avoid infection and stop the bleeding. If required a couple of stitches may also be needed. Dressing of the wound may also be done.

Cryotherapy

Skin lesions in Multiple Keratoacanthoma are frozen using liquid nitrogen, or carbon dioxide snow, or dimethyl ether and propane. This liquid is applied with a cotton tipped applicator. The lesions will literally freeze and fall off the skin in this procedure. It is completely safe and relatively inexpensive to use cryotherapy as a treatment for Keratoacanthoma.

Radiotherapy

While not usually recommended for a single lesion, should the patient be suffering from Multiple Keratoacanthomas, radiation may be suggested. Radiation in small bursts is applied to the targeted cancerous tissue. The energy that is transmitted destroys the cancerous cells. The strength of radiation used will differ on individual basis.

Management of Keratoacanthoma

The individual who develops Keratoacanthoma once is at higher risk of developing it again. It is also likely to occur as Multiple Keratoacanthoma the second time, which is why the individual must regularly keep checking their skin for bumps. It would help to keep the skin protected from sun damage, as well as avoiding chemical carcinogens such as tobacco and cigarettes. Keeping such factors in check reduce the probability of developing Kerantoacanthomas.

While there is no direct evidence to support the fact that Keratoacanthoma is a genetic illness, it has been found to run in families. Multiple Keratoacanthoma is much more likely to be found in family members related by blood, which is why family medical history must also be shared with the health care provider. There is no underlying factor which causes the skin lesion and so it is difficult to predict who will be afflicted by it.

References -

http://www.aocd.org/?page=Keratoacanthoma
http://www.bad.org.uk/shared/get-file.ashx?id=96&itemtype=document
http://www.dovemed.com/diseases-conditions/keratoacanthoma/
http://www.pathologyoutlines.com/topic/skintumornonmelanocytickeratoacanthoma.html
https://patient.info/doctor/keratoacanthoma-pro