Rectal Cancer Recurrence at a Colostomy Site

What happened, in summary

A 59-year-old woman with mucus leakage and anal incontinence was found to have a large rectal carpet adenoma extending from the dentate line to the rectosigmoid junction. She underwent intersphincteric abdominoperineal resection using a transanal total mesorectal excision approach, with an end colostomy. An abnormal appendix was also removed. Pathology found a 20 mm moderately differentiated rectal adenocarcinoma within the large polyp. The final classification was T2N0M0, with clear resection margins.

Three months later, an enlarged external iliac lymph node was investigated with imaging, needle sampling, and groin dissection. The removed tissue was reactive and contained no cancer.

Twenty-one months after the rectal operation, a 15 mm hard mass appeared at the skin junction of the colostomy. Biopsy confirmed mucinous adenocarcinoma related to the rectal primary. Further imaging showed a 5.6 cm mass invading the left rectus muscle, additional abdominal-wall nodules up to 2 cm, and peritoneal nodules. She received palliative radiotherapy of 20 Gy in 5 fractions. She was alive 6 months later. Chemotherapy was still being considered but had not started.