A 29-year-old male visited our hospital because of lower abdominal pain. Acute appendicitis was suspected, and surgery was performed. However, no abnormality was found in the vermiform appendix. Instead, atrophy of the greater omentum, numerous nodes of varying sizes, and a small amount of ascites were observed. On the basis of histological examination, a diagnosis of metastatic glandular cancer was made. Gastric fluoroscopy performed 2 months earlier in another hospital had revealed irregularity of the stomach wall and a large concave area on the side of the greater curvature. Photogastroscopy and CT demonstrated progressive Borrmann type III cancer at the corresponding site and metastasis to regional lymph nodes. Biopsy findings were similar to the histological findings. After 1 week, treatment with UFT (400 mg/day), MMC (10 mg/month) and LNT (1 mg/week) was initiated. After about 3 months, i.e., following administration of 40 g UFT, 30 mg MMC and 8 mg LNT, gastric fluoroscopy and photogastroscopy revealed complete disappearance of the tumor. No abnormality was found by laboratory studies. The patient has since returned to a normal life.