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[A Case of Local Recurrence with Negative FDG/PET Findings after a Total Proctocolectomy for Ulcerative Colitis Associated with Colon Cancer with Retroperitoneal Penetration].

We report the case of a 55-year-old man who successfully underwent resection of a recurrence of ulcerative colitis(UC)- associated colon cancer located in the pancreatic body and left kidney. The patient had undergone an emergency laparotomy (total proctocolectomy with stapled ileal-pouch anal anastomosis)for the treatment of a descending colon cancer with retroperitoneal penetration associated with UC at the age of 50 years. At that time, histological examinations revealed a mucinous carcinoma that was classified as Stage II colon cancer. Three years after the patient's initial operation, a CT scan revealed a small mass located between the pancreatic tail and the left kidney. However, the accumulation of FDG was not observed during a positron emission tomography(PET)examination, resulting in close observation. As the size of the tumor and the levels of serum carcinoembryonic antigen and carbohydrate antigen 19-9 gradually increased, recurrence was highly suspected. A distal pancreatectomy and left nephrectomy were performed. Pathological examination showed findings concurrent with a local recurrence of colon cancer. Special histological types, such as mucinous carcinoma, often occur in some colitic cancers. For the postoperative surveillance of patients with colitic cancer, it should be noted that the sensitivity of FDG/PET is lower for mucinous carcinoma of the colon than it is for more common colon cancers.