A study to evaluate the safety and efficacy topical squaric acid dibutylester (SADBE) for the neoadjuvant treatment of congenital melanocytic nevi (CMN).

Patients with CMN and plans for elective surgical resection of their nevi will be enrolled in the study. Two clinically similar areas within the planned excision site will be identified, marked and treated with SADBE or the placebo solution. Following surgical resection, samples from the excised nevi will be taken and assessed for number of melanocytes. Incidence of adverse events will also be collected.

Inclusion Criteria:

• 18 years of age or older.
• Subject or parents willing and able to give informed consent, and assent as appropriate.
• Patients who have a clinical diagnosis of CMN with plans for elective non-urgent excision of part or all of their nevus, with nevus surface area of > 6 cm2.

Exclusion Criteria:

• Immunosuppressive therapy with glucocorticoid or other systemic immunosuppressant within 4 weeks of recruitment (except for inhaled corticosteroids for asthma).
• History of malignancy.
• History of organ transplantation.
• Known immunosuppressive disease, including infection with HIV.
• Severe medical comorbidities (diabetes mellitus requiring insulin, CHF of any severity, MI, CVA, or TIA within 3 months of screening visit, unstable angina pectoris, oxygen-dependent severe pulmonary disease)
• Subject is currently enrolled in another investigational device or drug trial(s), or subject has received other investigational agent(s) within 28 days of baseline visit.
• Subjects who have known hypersensitivity to SADBE or any of its components.
• Any condition judged by the investigator to cause this clinical trial to be detrimental to the patient.

Assessors will be blinded on what area received the study cream and what area received the placebo ethanol solution.