We report herein the case of an 81-year-old woman found to have small intestinal carcinoma producing carbohydrate antigen (CA)19-9, in whom recurrence on the abdominal wall was strongly suspected 4 months after resection. She presented to our hospital with acute abdominal pain with severe anemia. Marked serum elevation of CA19-9 to 164.8 U/ml suggested a progression to malignancy. A fluorography using an ileus tube revealed an abnormal mucosal pattern. An exploratory laparotomy showed an incomplete annular constrictive Borrmann type 2 tumor, located approximately 190 cm from Treitz's ligament, without any signs of peritoneal or hepatic metastases. Histological examination confirmed a diagnosis of papillotubular adenocarcinoma without metastases of the regional lymph nodes. CA19-9 antigenicity was detected in the cytoplasm and on the surface of the cancer cells, using the monoclonal CA19-9 antibody, NS19-9. In this report, we demonstrate the CA19-9 productivity and distribution of the cancer tissues in relation to their prognosis.