[A Case of Invasive Ductal Carcinoma in the Fat Replacement of the Pancreatic Body and Tail].

A 56 year-old woman with obesity (BMI3 2) and diabetes mellitus was diagnosed with right renal cell carcinoma. She underwent right nephrectomy 1 year ago. Seven months after surgery, CT revealed a rapidly growing mass near the spleen. The mass showed slight accumulation of FDG (SUVmax=2.4) on PET-CT. Since the lesion grew rapidly and was not enhanced in the early phase of enhanced CT, we diagnosed pancreatic cancer. Distal pancreatectomy and splenectomy were performed. The final pathological diagnosis was invasive ductal carcinoma in the fat replacement of the pancreatic body and tail. Postoperatively, the patient had no complications such as pancreatic fistula or aggravation of glucose intolerance. She received postoperative chemotherapy with gemcitabine. Since she developed pulmonary artery thrombosis, postoperative chemotherapy was interrupted after 8 courses. Thirty-two months after the surgery, she was still living without any recurrence. Acinar cells were absent in the fat replacement of the pancreas, but the pancreatic duct cells were still present. There was carcinoma in situ in the main pancreatic duct surrounding chronic inflammation. Fat replacement itself could be potentially precursor of the pancreatic cancer.