Actinic keratoses


A form of squamous cell carcinoma in situ.

The most frequent pre-malignant skin disease in the white population. 

Found on sun damage skin, particularly the face, scalp, arms, and legs.

Estimated 58 million Americans have actinic keatosis.

Described as rough adherent scale on an erythematous nonindurated base that is occasionally friable.

Rapidly expanding lesions that become indurated or excessively hyperkeratosis should be biopsied to rule out transformation to squamous cell carcinoma.

Caused by exposure to ultraviolet radiation.

Prevalence of 37.5% among whites 50 years of age or older.

Actinic keratosis is one of the most frequent reasons for patients to visit a dermatologist.

Strong correlation between the amount of sun exposure and the number of keratoses present.

Commonly affects men, persons with fair skin, persons with a history of prolonged exposure to ultraviolet light, and older individuals.

Earliest clinical stage in the evolution of squamous cell carcinoma of the skin.

If left untreated may develop into squamous cell carcinoma. 

If left untreated AK may progress to invasive cutaneous squamous cell carcinoma with a reported risk of progression ranging from 0.025-16% per lesion per year.

No definable clinical characteristics distinguish which actinic keratosis lesions are at risk and what proportion of such lesions will progress into carcinoma.

Percentages have reported to range from for. 025-16% actinic lesions per year.

Because of its unpredictable nature of progression, treatment of all actinic keratoses is recommended

Confined to the epidermis.

Typically occurs on sun exposed areas.

The incidence increases with age.

May be solitary, or there may be several on sun exposed areas.

Patients are encouraged to use sunscreen daily.

Transformation to squamous cell carcinoma estimated to occur in 1-10% of lesions.

About 0.1-0.6% of lesions transform to squamous cell carcinomas.

Progression to invasive squamous cell carcinoma of about 0.085% per lesion per year.

The presence of inflammation, induration, and oozing may suggest the presence of a true malignancy.

Evidence that AKs are premalignant and that p53 and p16 tumor suppressor mutations are found in these lesions and in squamous cell carcinoma of the skin.

Clinical variations include cutaneous horns, pigmented actinic keratoses and actinic cheilitis.

Biopsy which can be incisional or excisional, depending upon the size of the lesion, is required for diagnostic purposes.

AKs contiguous to primary squamous cell skin cancers in 44% of cases of metastatic squamous cell carcinoma.

82+ percent of squamous cell carcinomas of the skin occurred with concomitant AKs.

Most common indication for surgery is when transformation into a squamous cell cancer is suspected.

Cryosurgery first choice for management.

Solitary lesions can’t be treated with cryotherapy.

Patients often present with multiple lesions in one continuous field: field change.

Field-directed therapies are effective for present actinic keratoses but also may have a prophylactic effect on the development of new lesions, and they may prevent the development of squamous cell carcinoma. 

Treatment of multiple lesions and surrounding sun damage skin includes topical agents: fluorouracil, diclofenac, imiquimod or Ingenol mebutate and photodynamic therapy.  

Topical agents may be associated with local reactions of pain, irritation, erosions, ulcerations, and irreversible skin changes of pigmentation and scarring. 

Topical agents have to be administered sometimes over weeks or months which may reduce adherence and undermine treatment success.

Associated with a high recurrence rate after treatment.

If solar lesions are numerous topical 5 FU may be preferred treatment.

The effect of the 5-FU on actinic keratoses reduction can last for years.

Cumulative exposure to sunlight within the last 10 year strongly associated with risk of actinic keratoses.

Histologically characterized by partial thickness disordered atypical epidermal keratinocytes and thickened compact stratum corneum.

The two main approaches to treatment are: destruction of isolated lesions or treating large areas of skin-field therapy.

Isolated lesions can be treated with cryotherapy, trichloroacetic acid, or curettage and electrodessection.

Field therapy can be accomplished by: topical fluorouracil, diclofenac sodium, imiquimod, ingenol mebutate, and photodynamic therapy.

In a trial of field therapy comparing 5-FU 5% cream, 5% in imiquimod cream, methyl aminolevulinate, photo dynamic therapy or 0.015% ingenol mebutate cream- 5 FU was the most effective at 12 months.(Jansen M).

Liquid nitrogen cryosurgery most common treatment.

For more extensive lesions curettage, chemical peels, dermabrasion, and laser are effective treatments.

When treating actinic keratosis 5-fluorouracil and imiquimod demonstrated no difference in the prevention of site-specific keratinocyte carcinoma during the short- or long-term.

Actinic keratosis can progress to both basal cell carcinoma and squamous cell carcinoma.

Lifetime progression rates are estimated at between 0.1% and 20%, with the rate of malignant transformation of untreated actinic keratosis during a 5-year period being 5.58%.

If a patient exhibits multiple actinic keratoses at the same anatomical level, field treatments are advised to decrease the actinic keratoses burden, as well as the risk of later actinic keratosis and keratinocarcinomas in the treated area.

Surgery reserved for recalcitrant lesions or lesions suspected of being malignant.

Tirbanibulin 1% ointment is a synthetic inhibitor of tubulin polymerization And Src  kinase signaling.

Tirbanibulin induces p53 expression, arrests cell division and mitosis in proliferating cell  populations and subsequent apoptosis.

Tirbanibulin 1% ointment applied daily for five days was superior to placebo for the treatment of AK at two months, but is associated with local reactions and recurrence of lesions at one year.

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