Case Study of the Week: Actinic Keratosis

Skin cancers are the most common form of cancer in the United States.  One in five Americans will be diagnosed with skin cancer during the course of their lifetime.  Most types of skin cancer including actinic keratoses, basal cell carcinomas and squamous cell carcinomas are typically not fatal.  They can, however grow rapidly becoming disfiguring and invading surrounding tissues resulting in functional consequences.  More than 2 million cases of these types of skin cancer are treated each year in the U.S.  Actinic keratosis is the most common form of precancerous lesion affecting more than 58 million Americans.  The ability to recognize these types of skin cancers is essential for nurse practitioners in the primary care setting. 

Presentation

A 41 year-old male patient presents your clinic with a pinkish-colored, scaly, crusty growth to his left arm.  The lesion is not painful and he has not sustained any injury to this area.  The patient works as a truck driver and states he is concerned he could have skin cancer as his left arm is constantly exposed to sunlight while he drives.  The patient has no known medical history and his vital signs are stable.  On examination of the lesion you note it is non-tender and shows no signs of infection such as surrounding erythema or drainage.  The lesion is about 7mm in diameter.  You suspect this lesion is an actinic keratosis and elect to perform a skin biopsy to confirm your diagnosis. 

Management and Outcomes

Multiple treatment options exist for these skin lesions.  A skin biopsy is indicated to rule out squamous or basal cell carcinoma.  Most commonly, actinic keratoses are treated with cryotherapy; frozen off with liquid nitrogen.  These lesions may also be cut off under local anesthesia.  Creams containing 5-fluorouracil are also affective against actinic keratosis.  These medications cause the lesion to become red, inflamed and eventually fall off.  Although effective, they cause slight pain and must be used for weeks making them impractical for use in some patients. Aldara and Diclofenac creams are also effective with similar effects to 5-fluorouracil.

Discussion

Actinic keratoses are caused by prolonged exposure to sunlight and are most commonly observed in fair-skinned individuals over the age of 40.  Approximately 25% of these lesions resolve spontaneously while about 10% develop into malignant squamous cell carcinoma.  Studies show that nearly 65% of squamous cell carcinomas and 36% of basal cell carcinomas arise from clinically diagnosed actinic keratoses.  It is not possible to determine which actinic keratoses will become malignant therefore each lesion must be treated appropriately. 

References

Center for Disease Control and Prevention. Skin Cancer. http://www.cdc.gov/cancer/skin/

American Cancer Society. Cancer Facts and Figures 2010. http://www.cancer.org/acs/groups/content/@nho/documents/document/acspc-024113.pdf

Skin Cancer Foundation. Skin Cancer Facts. www.skincancer.org

Spencer, James. Actinic Keratosis. Medscape Reference, http://emedicine.medscape.com/article/1099775-overview

Comments

case study AK

Jessica