PANCREATITIS, OTHER INFLAMMATORY LESIONS, AND PANCREATIC PSEUDOTUMORS Alton B. Farris III, MD a, *, Olca Basturk, MD b , N. Volkan Adsay, MD c ABSTRACT T he pancreas is versatile in the diversity of disorders that it can exhibit. In this article, characteristics of disorders such as chronic, autoimmune, eosinophilic, hereditary, and infec- tious pancreatitis are described. With regard to autoimmune pancreatitis, the role of clinical evalu- ation, histologic examination, and IgG4 immuno- histochemistry is discussed. The role of pancreatitis in the pathogenesis of diabetes is also mentioned. Some implications of pancreatitis are highlighted, including the neoplastic predispo- sition caused by inflammatory lesions of the pancreas. The goal of this article is to convey an appreciation of these disorders because recog- nizing these disorders can benefit patients tremen- dously, as inflammatory lesions of the pancreas can be mass-forming, giving rise to pseudotu- mors, leading to surgical resection that may other- wise be unnecessary. OVERVIEW: INFLAMMATORY LESIONS OF THE PANCREAS The pancreas is a complex organ owing to the large number of neoplastic, inflammatory, and pseuodoneoplastic lesions that it may contain. Because of its important endocrine and exocrine functions and its central anatomic location, abnor- malities in the pancreas can manifest in a dramatic fashion. This article focuses on inflammatory lesions of the pancreas as well as some benign pancreatic lesions that may be mistaken for neoplasia by clinicians, radiologists, and even pathologists. The article attempts to aid the pathologist in confronting the differential diagnosis of these important entities. INFLAMMATORY LESIONS OF THE PANCREAS ACUTE PANCREATITIS Acute pancreatitis (Fig. 1) is characterized clinically by upper abdominal pain, epigastric pain, and pancreatic enzyme (lipase or amylase [hyperamylasemia]) elevation, detectable in either the blood or urine. Other signs and symptoms may be present including nausea, vomiting, and fever. Abnormal laboratory values that may also be present include a transient hyperglycemia, hypertriglyceridemia, and hypocalcemia. 1,2 Criteria used for the prediction of pancreatitis severity include the Atlanta classification, 3 Ranson’s Disclosures: None. a Department of Pathology and Laboratory Medicine, Emory University Hospital, Emory University, 1364 Clifton Road Northeast, Room H-188, Atlanta, GA 30322, USA b Department of Pathology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA c Department of Pathology and Laboratory Medicine, Emory University, 1364 Clifton Road NE, Room H-180B, Atlanta, GA 30322, USA * Corresponding author. E-mail address: abfarri@emory.edu KEYWORDS  Pancreatitis  Diabetes  Pseudotumors  Pathology  Pancreas  Inflammatory lesions  Autoimmune Surgical Pathology 4 (2011) 625–650 doi:10.1016/j.path.2011.03.004 1875-9181/11/$ – see front matter Ó 2011 Elsevier Inc. All rights reserved. surgpath.theclinics.com