Four groups of 10 patients each receive topical HPMPC at 0.3 percent concentration for 5 or 10 days total or 1.0 percent concentration for 5 or 10 days total, followed by 2 weeks of rest. When six patients at a given dose and schedule have completed treatment and follow-up without significant toxicity, subsequent patients are entered at the next higher dose level. Patients are evaluated twice weekly during treatment and once weekly during the rest period. HPMPC may be extended for up to two additional courses in patients who experience no significant toxicity.