What happened, in summary

A 79-year-old man was admitted after more than a year of profuse mucus secretion and watery diarrhea, which had worsened to as many as 10 episodes per day. He developed severe dehydration, electrolyte disturbance and acute kidney failure that required intensive care and emergency dialysis.

Imaging and colonoscopy showed a large rectal villous tumor. Initial biopsies found high-grade dysplasia, and a less invasive piecemeal polypectomy was attempted after his condition stabilized. The mucus loss continued, so the care team proceeded with an open abdominoperineal resection.

Final pathology showed a 9-centimeter villous adenoma containing a small Grade 1 adenocarcinoma with superficial submucosal invasion. The resection margins were clear and no lymph-node metastases were found. The oncology team recommended surveillance rather than adjuvant treatment. He recovered smoothly, was discharged on postoperative day eight, and had substantial improvement in strength and quality of life during the first month after surgery.