Type 1 Autoimmune Pancreatitis Extending along the Main Pancreatic Duct: IgG4-related Pancreatic Periductitis

• Published in: Internal Medicine Vol. 60; no. 5; pp. 739 - 744
• Main Authors: Sato, Junya, Matsubayashi, Hiroyuki, Ishiwatari, Hirotoshi, Satoh, Tatsunori, Kaneko, Junichi, Ishikawa, Kazuma, Yoshida, Masao, Takizawa, Kohei, Yabuuchi, Yohei, Kishida, Yoshihiro, Imai, Kenichiro, Hotta, Kinichi, Uesaka, Katsuhiko, Sasaki, Keiko, Ono, Hiroyuki
• Format: Journal Article
• Language: English
• Published: Japan The Japanese Society of Internal Medicine 01.03.2021; Japan Science and Technology Agency
• Subjects: Aged; Autoimmune Diseases - diagnosis; Autoimmune Pancreatitis; Case Report; Cysts; diagnosis; Diagnosis, Differential; Humans; IgG4; Immunoglobulin G; Internal medicine; intraductal neoplasms; Lesions; Male; Pancreas; Pancreatic Ducts; Pancreatic Neoplasms - diagnosis; Pancreatitis; Pancreatitis - diagnosis; periductitis; periductitis; IgG4; autoimmune pancreatitis; diagnosis; intraductal neoplasms
• ISSN: 0918-2918; 1349-7235
• DOI: 10.2169/internalmedicine.5754-20

We herein report a unique form of autoimmune pancreatitis (AIP) spreading along the main pancreatic duct (MPD). A 70-year-old man was referred for a small lesion at the pancreatic neck, accompanying an adjacent cyst and dilated upstream MPD. Four years earlier, health checkup images had shown a pancreatic cyst but no mass lesion. Endoscopic ultrasonography showed a contrast-enhanced, tumorous lesion, mainly occupying the MPD. With a preoperative diagnosis of ductal neoplasms mainly spreading in the MPD, Whipple's resection was performed. The resected specimens showed MPD periductitis with IgG4-related pathology, indicating type 1 AIP. Clinicians should practice caution concerning the various AIP forms.