DISEASE CHARACTERISTICS: Clinically and histologically confirmed grade 1-3 actinic keratoses At least 2 actinic keratoses on each arm

PATIENT CHARACTERISTICS: Age: Over 18 Performance status: SWOG 0-1 Karnofsky 70-100% Life expectancy: Not specified Hematopoietic: Not specified Hepatic: Not specified Renal: Not specified Other: No prior invasive malignancy within past 5 years except nonmelanomatous skin cancer, stage I carcinoma in situ of the cervix, or stage 0 chronic lymphocytic leukemia No severe metabolic disorder No life threatening acute or chronic disease No medical condition that would preclude study No active systemic infectious disease that may affect immune system No prior keloid formation Not pregnant or nursing Negative pregnancy test

PRIOR CONCURRENT THERAPY: Biologic therapy: At least 2 months since prior immunotherapy Chemotherapy: At least 2 months since prior topical application of fluorouracil or masoprocol for actinic keratoses At least 2 months since prior systemic chemotherapy No further anticipated chemotherapy Endocrine therapy: At least 2 weeks since prior topical corticosteroids to target lesions At least 4 weeks since prior systemic steroid therapy Radiotherapy: No anticipated radiotherapy Surgery: Not specified Other: At least 2 weeks since prior other topical medications (e.g., retinoids or alpha hydroxyacids such as glycolic acid or lactic acid) At least 2 months since prior cryotherapy to target lesions At least 2 months since prior systemic psoralens or retinoids At least 2 months since prior laser resurfacing or chemical peels At least 30 days since prior other investigational drug No other concurrent topical medication to areas being studied