Pancreato-biliary malignancies often present with locally advanced or metastatic disease. Surgery is the mainstay of treatment although less than 20% of tumours are suitable for resection at presentation. Common sites for metastases are liver, lungs, lymph nodes and peritoneal cavity. Metastatic disease carries poor prognosis, with median survival of less than 3 mo. We report two cases where metastases from pancreato-biliary cancers were identified in the colon and anal canal. In both cases specific immunohistochemical staining was utilised in the diagnosis. In the first case, the presenting complaint was obstructive jaundice due to an ampullary tumour for which a pancreato-duodenectomy was carried out. However, the patient re-presented 4 wk later with an atypical anal fissure which was found to be metastatic deposit from the primary ampullary adenocarcinoma. In the second case, the patient presented with obstructive jaundice due to a biliary stricture. Subsequent imaging revealed sigmoid thickening, which was confirmed to be a metastatic deposit. Distal colonic and anorectal metastases from pancreato-biliary cancers are rare and can masquerade as primary colorectal tumours. The key to the diagnosis is the specific immunohistochemical profile of the intestinal lesion biopsies.
Keywords: Anal metastasis; Colonic metastasis; Immunohistochemistry; Pancreatobiliary cancer; Rare metastatic sites.