Case ReviewsAutoimmune Pancreatitis: Pancreatic Manifestation of IgG4-Related DiseaseNotohara, Kenji MD, PhD*; Arimoto, Maya MD†; Wani, Yoji MD, PhD*; Fujisawa, Masayoshi MD, PhD‡Author Information From the Departments of *Pathology and †Radiology, Kurashiki Central Hospital, Kurashiki; and ‡Department of Laboratory Medicine, Himeji Red Cross Hospital, Himeji, Japan. This work was supported in part by the Health and Labour Sciences Research Grants (Intractable Diseases) from Japan's Ministry of Health, Labour and Welfare. Reprints: Kenji Notohara, MD, PhD, Department of Pathology, Kurashiki Central Hospital, 1-1-1 Miwa, Kurashiki 710-8602, Japan. E-mail: [email protected]. Pathology Case Reviews: November-December 2010 - Volume 15 - Issue 6 - p 219-224 doi: 10.1097/PCR.0b013e3181ffb6d0 Buy Metrics Abstract Autoimmune pancreatitis (AIP) is a unique inflammatory disorder of the pancreas. Two histological types are recognized: lymphoplasmacytic sclerosing pancreatitis and idiopathic duct-centric chronic pancreatitis, with the former representing the pancreatic manifestation of IgG4-related disease. Presented here is a 64-year-old man who was incidentally found to have a mass in the pancreatic tail. The resected specimen revealed typical histological features of lymphoplasmacytic sclerosing pancreatitis, consisting of storiform fibrosis, obliterative phlebitis, and characteristic lobular and ductal inflammation. IgG4-positive plasma cells were numerous, and his serum IgG4 level was elevated (436 mg/dL). He also had systemic lesions, such as hypophysitis, bilateral eyelid lesions and bilateral pleural thickening, that most likely represented IgG4-related disease. Sometimes the distinction of AIP from cancer is clinically difficult, especially in cases with a localized lesion and/or without serological abnormalities; thus, pancreatic resection may be carried out. Pancreas biopsy is attracting attention as a diagnostic tool, and pathologists may play an important role in diagnosing AIP in the future. © 2010 Lippincott Williams & Wilkins, Inc.