Colorectal tumor recurrence on a mysterious spot

Question: A 74-year-old man was referred for colonoscopy because of rectal blood loss. His medical history included sarcoidosis, myocardial infarction, coxarthrosis, and late-onset allergic asthma. During colonoscopy, a sessile polyp was seen, located 15 cm from the anus (Figure A). The lesion was initially suspected to contain invasive cancer. Therefore, several biopsy specimens of the tumor were taken, followed by the placement of 3 distal tattoo markings (Figure B).