Abstract
The patient was a 74-year-old woman who had undergone subtotal stomach-preserving pancreatoduodenectomy for invasive ductal carcinoma. After undergoing postoperative adjuvant Titanium silicate (TS-1) chemotherapy for 6 months, she was followed up at an outpatient clinic, and cancer antigen (CA) 19-9 was found to be elevated during a regular examination 18 months post-surgery. A contrast-enhanced abdominal computed tomography (CT) scan revealed a low-density area in the pancreas body ; thus, the patient was diagnosed with residual pancreatic cancer and underwent completion pancreatectomy. Pathological examination revealed the tumor as an adenosquamous carcinoma, which was subsequently diagnosed as a metachronous pancreatic cancer based on the fact that the histological diagnosis of the initial and residual cancer differed from one another, and because both pancreatic margins were negative. This is the second reported case of residual pancreatic adenosquamous carcinoma cancer in Japan. Invasive ductal carcinoma is associated with poor prognosis ; however, recently there have been several reports of residual pancreatic resection for metachronous pancreatic cancer. During follow up after surgery for pancreatic cancer, it is extremely important to consider both postoperative recurrence as well as potential development of metachronous pancreatic cancer.
