It is important in the clinical setting to integrate all of the findings when diagnosing and making treatment decisions. We report a case of particular interest for managing cancer patients. A 69-year-old man underwent endoscopic resection for an Rb rectal tumor. The tumor showed a positive vertical margin and required laparoscopy-assisted super low anterior resection with ileostomy for histopathological stage Ⅰrectal cancer. His postoperative course was uneventful. The follow-up computed tomography (CT) scan revealed a tumor locating close to the left common iliac artery. Although positron emission tomography (PET) showed 18F-fluorodeoxyglucose (FDG) accumulation in the tumor, none of the other clinical findings indicated a recurrence of rectal cancer. FDG is not specific to malignant neoplasias, but the location of the tumor and the FDG uptake suggested the possibility of malignancy. No other tests found any evidence of a recurrence. Tumor resection was performed concurrently with ileostomy closure. Histopathology demonstrated it was an asymptomatic abscess in a lymph node. Tumor recurrence and metastases have to be kept in mind even if the primary lesion is in an early stage. This case shows the difficulty in deciding how to manage patients when clinical results are not consistent, especially in cases needing surgical procedures.