An actinic keratosis, also known as a solar keratosis, is a common premalignant skin lesion. An actinic keratosis occurs when the cells that comprise 90 percent of the epidermis, the keratinocytes, change their size, shape or organization in a process called cutaneous dysplasia.This alters the texture of the skin surface and may extend deeper, into the dermis.
Causes of an Actinic Keratosis
Such a lesion is typically caused by chronic exposure to sunlight, particularly ultraviolet light and is therefore mainly found on areas of the body most frequently exposed to the sun. While not a skin cancer, an actinic keratosis, left untreated, may develop into an squamous cell carcinoma, a form of skin cancer capable of metastasizing and even resulting in death. Although not dangerous in itself, an actinic keratosis must always be taken seriously and examined and treated by a dermatologist.
Symptoms of an Actinic Keratosis
An actinic keratosis appears as a scaly reddish or tan lesion on the epidermis, or surface layer of the skin. It may manifest as rough or scaly skin, bumps, mottled patterns, or protrusions called cutaneous horns. Actinic keratoses usually appear on the face, including the ears and lips, or on the neck, arms and hands.The lesions may range in size from a pinpoint to several centimeters in diameter and may be yellow, brown, red or violet in color, and smooth, wrinkled or furrowed in texture.
Risk Factors for an Actinic Keratosis
Fair-skinned individuals, aged 40 to 50 years of age, are more prone to actinic keratosis. Nonetheless, individuals of any age may develop such lesions, particularly in warm, sunny climates. Teenagers are often diagnosed with the condition. Actinic keratosis is also more likely to occur in individuals who spend a great deal of time in the sun, or who frequent tanning parlors.
Diagnosis of an Actinic Keratosis
A dermatologist should always be consulted about any suspicious lesion on the skin. Unless such a lesion is immediately identifiable by the physician as benign, a surgical biopsy may be performed to determine whether it is premalignant or cancerous. The biopsy procedure is small and painless and takes place in the doctor's office. A pathology report will be available in a week or two to determine whether further treatment is necessary.
Treatment of an Actinic Keratosis
Depending on the location and severity of the lesion, an actinic keratosis may be treated in a number of ways. The patient and doctor will decide on methodology in consultation. These may include:
- Cryotherapy, or freezing
- Curettage, or scraping
- Application of cream or ointment
- Chemical peeling
- Photodynamic therapy using laser light
Prevention of Actinic Keratosis
Because individuals who have had an actinic keratosis are more likely to have another lesion of this type and are also at greater risk of developing a squamous cell carcinoma, they should always opt to have full body checks with their dermatologist at regular intervals. Patients who have been treated for this condition should also avoid sunlight as much as possible. When they are exposed to the sun, they should be careful to wear adequate protection, including sunscreen with an SPF of 30 or higher, protective sunglasses, long sleeves and long pants whenever possible, and wide-brimmed hats. They should also, of course, avoid tanning parlors.
Biopsy of Skin Lesions
A skin lesion biopsy is a diagnostic test that involves removing a tissue sample and examining it under a microscope. This test is used to identify suspicious lesions and to differentiate normal cells from abnormal ones.
Reasons for Skin Lesion Biopsies
Skin lesion biopsies are performed when simple visual examination by the physician is insufficient to make a clearcut diagnosis. Such biopsies are done in order to make a definitive diagnosis of:
- Skin infections which may be fungal, bacterial or viral
- Skin growths like moles, warts, or seborrheic keratosis
- Precancerous lesions like actinic keratosis
- Bullous pemphigoid and other blistering skin disorders
- Dermatitis, such as eczema or psoriasis
- Skin cancers, including basal cell, squamous cell, and melanoma
Types of Skin Lesion Biopsies
There are a number of different types of skin lesion biopsies, all of which are usually performed in the doctor's office. The method chosen will depend upon the appearance of the lesion or lump as well as its location and its size. An anesthetic will be applied to the skin regardless of which technique is used, and for some types of biopsy, stitches, or even skin grafts, may be required to restore the area. Most skin biopsy procedures take approximately 15 minutes to complete.
A shave biopsy is the least invasive method. It involves a simple shaving, with a razor or scalpel, of cells from the upper layers of the skin, the epidermis and part of the dermis.
A punch biopsy is a procedure for assessing growths or sores that penetrate more deeply into the skin. A rotational cutting device is used to remove a small cylindrical section of cells from the epidermis, the dermis and uppermost layer of fatty tissue.
An excisional biopsy surgically removes the entire lesion, including all three skin layers. In fact, if the affected area is of a considerable size, a skin flap or graft from another part of the body may be needed to cover the excision and replace the missing skin.
The Skin Lesion Biopsy Procedure
Before undergoing a skin biopsy, the physician should be notified if the patient has a bleeding disorder, is taking any blood-thinning medication, or has an autoimmune disorder or underlying skin condition. Since a local anesthetic will be administered prior to the biopsy, the procedure will not be painful.
Following the biopsy, the tissue sample is stored in a preservative solution or a sterile container until it can be processed at a pathology laboratory. Once the specimen has been prepared and thoroughly examined under a microscope, a diagnosis will made to determine what the course of follow-up treatment, if any, should be.
Results and Further Treatment after Skin Lesion Biopsy
It may take several days to 2 weeks to receive laboratory results, depending on the type of biopsy that has been performed and on the types of testing required. Depending on what the laboratory results show, medication may be prescribed, further excision may be necessary, or, in the case of serious malignancy, radiation or chemotherapy may be required. In many cases, where the biopsy shows no abnormality, there will be no further treatment necessary.
Risks of a Skin Lesion Biopsy
Skin lesion biopsies are extremely safe procedures as evidenced by the fact that they are usually performed outpatient in the doctor's office and take only a short time to complete. In rare cases, skin biopsies may result in troublesome aftereffects, such as excessive bleeding, bruising, scarring, infection or allergic reactions. The vast majority of skin lesion biopsies, however, are uneventful.