Eosinophilic pancreatitis: a rare entity that can mimic a pancreatic neoplasm.

Eosinophilic pancreatitis is a rare disorder that is frequently diagnosed only after pancreatic resection for suspected pancreatic tumor. It typically occurs in the setting of either eosinophilic gastroenteritis or the hypereosinophilic syndrome. Isolated eosinophilic infiltration of the pancreas is less common. We describe a case of a 36-year-old man who presented with the clinical symptoms of acute pancreatitis. Radiologic evaluation revealed an obstructive pancreatic lesion suspicious for carcinoma. Pathologic examination of the resection specimen revealed a dense infiltrate of eosinophils in the pancreas. Although an uncommon condition, eosinophilic pancreatitis is a syndrome lacking well-defined causes that can be associated with eosinophilic gastroenteritis, a treatable condition, or the potentially fatal hypereosinophilic syndrome. While the radiographic features of this condition can vary widely, eosinophilic infiltration of the pancreas with or without involvement of the gastrointestinal tract is the pathologic feature common to all of the previously reported cases.