The study by Wataya-Kaneda et al1 in this issue of JAMA Dermatology examines the response of hypopigmented macules in tuberous sclerosis (TS) to topical rapamycin. The authors found that topical rapamycin, 0.2%, gel led to substantial improvement of hypopigmented macules without systemic absorption and that the improvement was more marked in sun-exposed skin. This improvement was reflected in the normalization of melanosome abnormalities in treated skin. Finally, the authors note that knockdown of tuberin (tsc2) caused abnormalities in melanosome numbers compared with controls.