A 76-year-old male with local recurrence after abdominosacral resection of recurrent rectal cancer was admitted to our hospital. Computed tomography (CT) and magnetic resonance imaging (MRI) indicated a recurrent tumor at the back of the prostate and seminal vesicles up to the resected sacral (S3) stump. However, positron emission tomography (PET)/CT fusion images showed no 18F-2-fluoro-2-deoxy-D-glucose (FDG) uptake at the pre-sacral region, which suggested postoperative scarring of the tissue. Based on the PET/CT diagnosis, we performed abdominoperineal en bloc resection of the recurrent tumor with bladder, seminal vesicles, prostate, internal obturator muscle, ischial spine, and gluteal muscle without resection of the sacrum. Specimen revealed no circumferential resection margin involvement by tumor on pathologic examination. The patient was discharged from the hospital on postoperative day 23 without major complications.