[A case of stage III B advanced gastric cancer with psoriasis vulgaris responding to S-1/CDDP neoadjuvant chemotherapy leading to a pathologically complete response].

A 39-year-old man with psoriasis vulgaris who complained of severe anemia was examined and diagnosed with advanced gastric cancer (UM, Type 3, cT3 cN2 cH0 cP0 cM0, cStage III B). He was treated with S-1/CDDP as neoadjuvant chemotherapy. S-1 (120mg/day) was administered orally for 14 days, followed by 7 drug-free days as a course, and CDDP (100mg/ body) was administered by intravenous drip on day 8. After the third course, a significant tumor reduction was obtained. Total gastrectomy and lymph node dissection (D2) were performed. The histological diagnosis revealed a complete disappearance of cancer cells in the stomach and all of the lymph nodes. He has been doing well without any recurrence for 9 months since the start of treatment.