[PET detection of recurring rectal adenocarcinoma in an unusual location. Case report].

A rare pattern of colon cancer recurrence is presented. A 63-year-old man underwent surgical resection after diagnosis of colon cancer. The postsurgical-pathologic examination showed a stage II colon cancer (MAC B2). Six courses of adjuvant chemotherapy (Mayo protocol) were started within four weeks of surgery. During follow-up, serial serum carcinoembryonic antigen levels became progressively elevated in an otherwise asymptomatic patient who showed no signs of recurrence in any of the conventional imaging tests performed (chest X-ray, abdominal ultrasound, and abdominal CT-scan). Positive findings suggesting lymph node mediastinal metastases were present in the PET scan. Surgical resection and pathologic examination demonstrated metastases of colon adenocarcinoma.