Emergency rectal obstruction caused by pancreatic cancer metastasizing to the rectum

Pancreatic cancer is an aggressive malignancy with a poor prognosis. Although distant metastases are common at the time of diagnosis, metastatic spread to the rectum is rare. Furthermore, there have been no reports of acute rectal obstruction caused by a metastatic rectal tumor from pancreatic cancer. A 75-year-old man presented with lower gastrointestinal bleeding, abdominal pain, and distention. Colonoscopy and abdominal computed tomography confirmed acute rectal obstruction. Additionally, computed tomography identified a tumor in the pancreatic tail. An emergency loop colostomy on the transverse colon was performed. During preoperative assessment, the patient was initially considered to have synchronous primary cancers of the rectum and pancreas. However, microscopic examination confirmed that the rectal tumor was a metastasis from pancreatic cancer. Chemotherapy for pancreatic cancer was initiated immediately, and as of this writing, the patient has survived for more than 1 year. In summary, we herein report a rare case of pancreatic cancer metastasizing to the rectum. The prognosis of pancreatic cancer with distant metastases may be improved by enabling early initiation of chemotherapy. Minimally invasive surgery could be an effective approach for managing rectal obstruction due to metastasis.