Pancreatic echinococcosis

Echinococcosis (hydatid disease) is caused by the larval stage of Echinococcus granulosus. It most frequently involves the liver, followed by the lung. Pancreatic echinococcosis is very rare, even in endemic areas, with an incidence of 0.14% to 0.2%. We describe a case of a 34-year-old woman who presented with epigastric pain for 1 month. Contrast-enhanced computed tomography demonstrated a 4.0-cm hypodense mass in the pancreatic head and an uncinate process with suggestion of hyperdense/enhancing curvilinear densities. Magnetic resonance imaging with and without intravenous contrast showed a nonenhancing cystic mass. Endoscopic ultrasound demonstrated a cystic structure with curvilinear floating membranes consistent with the water lily sign, pathognomonic of hydatid disease. Enzyme-linked immunosorbent assay for echinococcal antigen was positive.