Acinar cell carcinoma of the pancreas eroding the pylorus and duodenal bulb.

A 74-year-old woman presented at the National Defense Medical College Hospital in April 2001 with a chief complaint of upper abdominal pain. She had been diagnosed as having adenocarcinoma on the basis of results of examination of a biopsy specimen taken from an ulcer of the duodenal bulb at a local hospital. On admission, she showed no jaundice, but a hard mass, about 10 cm in diameter, was palpated in the right upper quadrant. Laboratory data showed high levels of serum carcinoembryonic antigen (CEA) and carbohydrate antigen (CA) 19-9. Abdominal computed tomography (CT) and angiography demonstrated a giant enhanced mass in a pattern of eccentric gradation extending to the pylorus, duodenal bulb, and pancreatic head. She underwent pancreatoduodenectomy with combined resection of the transverse colon. The histologic diagnosis was acinar cell carcinoma (ACC), originating in the pancreatic head and extending to the stomach, duodenum, and transverse colon, without any lymph node involvement. In most reported cases of ACC, the preoperative diagnosis was a pancreatic mass or endocrine tumor of the pancreas. The correct diagnosis in those cases was made by postoperative or postmortem pathological examination. If criteria for detecting the slight differences between ACC and endocrine tumors on some images were to be established, the diagnostic skill for ACC would improve dramatically.