[A case of hypopigmentation triggered by S-1].

Right partial glossectomy and supraomohyoid neck dissection were performed on a 65-year-old man with tongue squamous cell carcinoma. Postoperatively, S-1(80-120 mg/day)was administered as adjuvant chemotherapy. Six months later, an eruption accompanied by abdominal itching was recognized. Then leukoderma appeared on his face and both hands, continued to spread and it was diagnosed by dermatology as hypopigmentation. He has been doing well without any recurrence for 4 years, but the hypopigmentation remains unchanged.