Colon Metastasis from Pancreatic Cancer: A Case Report

Pancreatic cancer commonly metastasizes to the liver, lung or adrenal glands, but rarely spreads to the colon. We describe a case of a 65-year-old man with operation history of endoscopic submucosal dissection for rectal adenoma, who visited our department with a lesion in the sigmoid colon. A biopsy of the sigmoid pathologic lesion found heterologous cells in the muscularis mucosa, which indicated that this lesion did not originate in the colon. Abdominal enhanced CT results revealed a soft tissue mass in pancreatic tail and several masses in the liver and rectovesical pouch. 18-FDG PET-scan results showed pancreatic neoplastic mass. Biopsy result of pancreatic pathologic area was positive for ductal pancreatic adenocarcinoma. Immunohistochemical staining confirmed that the sigmoid lesion was a metastasis from a primary pancreatic adenocarcinoma—an unusual pattern of spread. The patient accepted chemotherapy after an oncologic evaluation. To our knowledge, there were only nine reported cases of metastatic pancreatic cancer spreading to the colon. This was a rare route of metastasis for pancreatic cancer. It is important to keep this possibility in mind when patients present with a colon lesion. Furthermore, our case highlights the importance of considering metastases when a colon mass is found in patients with a history of colon cancer, although primary colon cancer is still more likely.