Multiple polypoid colonic metastases from rectal adenocarcinoma with signet ring cells features: a case report

Background Multiple polypoid colonic metastases are very rare which mainly originated from gastric carcinoma or melanoma. For rectal cancers, liver, lung and peritoneum are the most common metastatic sites. Here we present an unusual case with rectal adenocarcinoma and metachronous multiple colonic polypoid metastases. Case presentation A 53-year-old man who underwent radical resection for rectal cancer 2 years ago was admitted to our department for an elevation of CEA level of 18.4 ng/ml. Colonoscopy revealed ten ivory rubbery colonic polypoid lesions (about 5 mm in diameters) in the large bowel which were confirmed as signet ring cell carcinomas (SRCC) by biopsy, but full-body contrast enhanced CT and PET-CT showed no other suspicious lesion. Seven weeks later, a laparoscopic total colectomy was performed and more than 50 polypoid lesions were observed throughout the mucosal surface of the large intestine which were confirmed as metastatic SRCC by postoperative pathological examination. All the 34 paracolic lymph nodes retrieved were involved. After 4 months, diffuse abdominopelvic and multiple bone metastases were identified by CT and the patient died of the disease 1 month later. Conclusion Here we present an unusual case of multiple colonic polypoid metastases of rectal adenocarcinoma. For SRCC that is prone to have disseminated micrometastases, colonic ‘polyps’ may be the early noticeable sign of undetectable and extensive tumor spread. Instead of surgical resection of ‘the confined disease in colon’, systemic treatment maybe a more appropriate choice.