title: Histopathologically proven autoimmune pancreatitis mimicking neuroendocrine tumor or pancreatic cancer.
abstract: Autoimmune pancreatitis (AIP) can be difficult to distinguish from pancreatic cancer. We report a case of histopathologically proven AIP mimicking neuroendocrine tumor (NET) or pancreatic cancer in a 53-year-old man. He was referred to our hospital for further evaluation of a pancreatic mass detected on ultrasonography at a medical check-up. Abdominal ultrasonography showed a 15-mm hypoechoic mass located in the pancreatic body. Computed tomography revealed a tumor without any contrast enhancement, and magnetic resonance imaging demonstrated the mass to be hyperintense on diffusion-weighted image. Endoscopic retrograde cholangiopancreatography revealed slight dilatation of a branch of the pancreatic duct without stricture of the main pancreatic duct. The common bile duct seemed intact. Under suspicion of a non-functioning NET or malignant neoplasm, laparotomy was performed. At laparotomy, an elastic firm and well-circumscribed mass was found suggestive of a non-functioning NET, thus enucleation was performed. Histopathologically, the lesion corresponded to AIP.
authors.affiliation: Department of Surgery, The Jikei University, Daisan Hospital, Tokyo, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Onda
authors.forename: Tomoyoshi
authors.initials: T
authors.lastname: Okamoto
authors.forename: Masaru
authors.initials: M
authors.lastname: Kanehira
authors.forename: Shuichi
authors.initials: S
authors.lastname: Fujioka
authors.forename: Tohru
authors.initials: T
authors.lastname: Harada
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hano
authors.forename: Masaharu
authors.initials: M
authors.lastname: Fukunaga
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Yanaga