Cohorts of 3-6 patients receive escalating doses of tretinoin liposome until the maximum tolerated dose (MTD) has been determined. The MTD is defined as the dose preceding that at which 2 of 3 or 2 of 6 patients experience dose-limiting toxicity. Once the MTD is determined additional patients are accrued and treated at that dose. (Phase I closed to accrual as of 9/24/03.)