Evaluate the Efficacy and Safety of Large-Scale Field-Directed Topical Therapy of Actinic Keratosis of the Chest w/Ingenol Mebutate 0.015%

Inclusion Criteria: 1. Male or female of at least 18 years of age. 2. Subjects willing to comply with study requirements. 3. The presence of four or more clinically typical actinic keratosis within one contiguous area of the chest that is 100cm2. 4. For female subjects of childbearing potential willing to use an acceptable form of birth control during the entire course of the study. All systemic birth control measures must be in consistent use at least 30 days prior to entry into the study. A female is considered NOT to be of childbearing potential if she is postmenopausal for at least one (1) year, without a uterus, without both ovaries or has had a bilateral tubal ligation. Acceptable methods of birth control are: oral contraceptives, contraceptive patches/rings/implants Norplant, Depo-Provera, double-barrier methods (e.g. condoms and spermicide) and abstinence. 5. Subjects willing to refrain from the use of topical products containing alpha-hydroxy acids, retinoic acid, retinol, salicylic acid, and vitamins C/D (or their derivatives) in the treatment area 7 Days prior to and during the entire study period Exclusion Criteria: 1. Known hypersensitivity, prior allergic reaction, or prior chest treatment with ingenol mebutate gel. 2. Treatment area containing hypertrophic or hyperkeratotic lesions, cutaneous horns or lesions that had previously not responded to other standard treatments. 3. Presence of any skin condition or disease that might interfere with the diagnosis and evaluation of study parameters (i.e., atopic dermatitis, eczema, psoriasis, seborrheic dermatitis). 4. Subjects receiving ablative laser treatments on their chest must have discontinued the treatment at least 6 months prior to entering the study. 5. Subjects receiving Intense Pulse Light treatments on their chest must have discontinued the treatment at least 30 days prior to entering the study. 6. Within 3 months of study entry treatments that may interfere with evaluation of the treatment area (e.g. other topical therapies for actinic keratosis of the chest, topical corticosteroids, topical retinoids, ultraviolet B phototherapy, or immunosuppressive, immunomodulating, or cytotoxic medications) or expected use of any of the above-mentioned therapies in the treatment area listed during the duration of the study. 7. Within 3 months of study entry topical treatment in the treatment area for actinic keratosis including, but not limited to imiquimond, 5- fluorouracil, diclofenac or liquid nitrogen. 8. Within 6 months of study entry treatments with Poly-L-lactic acid (PLLA; Sculptra Aesthetic) that may interfere with the evaluation of the treatment area. 9. Within 7 days of study entry use of self-tanners, excessive exposure to sunlight or artificial UV light (e.g.: use of tanning beds/booths and/or sunbathing) or expectations of any listed during the time of the study within the treatment area. 10. Any systemic disease that is not yet stabilized for at least six (6) Months prior to entering study. 11. A significant history or current evidence of a medical, psychological or other disorder that, in the investigator's opinion, would interfere with the objectives of the study 12. Pregnant or nursing women or women planning a pregnancy during the study period. 13. Any unhealed skin lesions or wounds within the treatment area. 14. Existence of one (1) or more suspected basal cell carcinoma or squamous cell carcinoma within the treatment area. 15. Current participation or participation within 30 days prior to the start of this study in a drug or investigational device research study.