Case History/Examination
A 73-year-old man underwent sigmoidectomy with lymph node dissection for
stage Ⅱ sigmoid colon cancer 4 years ago. Afterward, he was carefully
monitored using chest- and abdominal computed tomography (CT), serum
tumor markers, and colonoscopies. No evidence of metastasis or
anastomotic recurrence was observed until 4 years and 3 months
postoperatively when he experienced anal bleeding during defecation,
initially felt to be caused by internal hemorrhoids. Anal examination
revealed a pink, firm perianal tumor (Figure A). On biopsy, the sample
showed heterotypic columnar epithelium arranged in irregular duct-like,
amalgamation duct-like, and comb-like configurations under stratified
squamous epithelium, indicating that the tumor was a metastasis of the
colonic adenocarcinoma (Figure B). The patient was oxygen-dependent due
to pulmonary fibrosis and emphysema, and had a history of rheumatoid
arthritis and variant angina, which contraindicated rectal amputation.