The case is of a 62-year-old man with no medical history and no family history.A type 2 tumor was found in the entire circumference of the sigmoid colon by colonoscopy after a positive result on a fecal occult blood test, and 5 liver metastases were recognized in both lobes of the liver by using contrast-enhanced CT.He was first treated by primary tumor resection. Subsequently, 5-fluorouracil/l-leucovorin/oxaliplatin (mFOLFOX6) plus bevacizumab (BV) was started 1 month after the surgery and a total of 8 cycles of mFOLFOX6 plus BV were administered without any adverse events.On CT assessment after the chemotherapy, the patient was diagnosed with stable disease according to RECIST guidelines since the size of the tumor only showed a slight reduction.However, it was considered to be an optimal response based on the morphologic criteria. Thereafter, a medial segmentectomy and partial resection of the liver was performed.A mucus reservoir was found in the tumor site, and no viable tumor cells were detected pathologically, which confirmed the pathological complete response with mFOLFOX6 plus BV.