Treatment with steroid tape is the standard of care for keloid and hypertrophic scars in Japan. In this article, we present a woman with an aggressive and progressive keloid of the anterior chest wall. At the time of presentation, the keloid had been present for 40 years, and was continuing to worsen and expand. Initially, it was believed that a multidisciplinary approach, including surgery and radiation, would be necessary to achieve an acceptable scar outcome. However, we successfully treated her keloid using only steroid tape (deprodone propionate plaster), and no other treatment modality. The case therefore supports the effectiveness of deprodone propionate plaster, and emphasizes its potential for wider future use. With the paucity of experience reported in the literature on steroid tape for scars, more reports are useful to inform plastic surgeons and dermatologists worldwide about this therapeutic option.