Pancreatic metastases to the rectum: a case report and literature review

Pancreatic cancer is one of the most malignant tumors due to its highly aggressive nature, but pancreatic metastases to the colorectum are extremely rare. A 43-year-old male patient complained of increased stool frequency. Colonoscopy revealed a prominence lesion in the rectum and computed tomography (CT) scan confirmed a rectal mass. CT scan also showed retroperitoneal masses in the pancreatic tail involving the spleen and adjacent blood vessels. The patient was initially misdiagnosed as having rectal cancer with pancreatic metastasis. After immunohistochemical staining results became available, the diagnosis was changed to pancreatic ductal adenocarcinoma with rectal metastasis. Elevated CA19-9 also supported the diagnosis. In conclusion, we describe a case of synchronous colonic metastasis from pancreatic cancer. Although rare, the suspicion of pancreatic metastases to the rectum should be excluded when a patient has both rectal and pancreatic masses.