Rectal cancer metastasis to the head of the pancreas treated with pancreaticoduodenectomy

We report a case of a 50-year-old man who developed metastatic pancreatic cancer from a primary rectal cancer that had been curatively removed 3 years previously. The patient presented with a tumor that occupied the head of the pancreas, associated with obstructive jaundice, but the main pancreatic duct was not dilated. The patient was initially diagnosed as having primary pancreatic cancer. Cytological examination of the bile was conclusive for the presence of adenocarcinoma. The patient refused surgical treatment and chose to have gemcitabine therapy (1000 mg/body), which was given 27 times over 10 months. For 1 year, local disease progression was slow and no distant metastases developed; therefore, the initial diagnosis of pancreatic cancer was questioned. At that time, the patient asked for the tumor to be removed, and pancreaticoduodenectomy was performed. On histology, including immunohistochemical staining for cytokeratin 20 (positive) and cytokeratin 7 (negative), the tumor was shown to be a metastatic pancreatic carcinoma that had originated from the original rectal cancer.