Hydatid cyst of the gall bladder-A rare location

A 70 year old female presented with intermittent, dull aching pain in right upper abdomen lasting for four months . Examination revealed hepatomegaly and a hard globular swelling continuous with the right costal margin. Enzyme linked immunosorbant assay for hydatid was positive. Ultrasonography of abdomen revealed a large multicystic lesion in right lobe of the liver and hyperechoic shadows in gall bladder fossa. Contrast enhanced computerized tomography of abdomen documented huge hydatid cyst in right lobe of liver and a thick walled calcified cystic lesion in segment-VI of the liver which was confirmed as a gall bladder at laparotomy. Histopathological examination of the specimen confirmed hydatid cyst of the gall bladder. Larval stage of echinococcus causes hydatid disease. Four species can produce disease in humans. E. granulosus and E.multilocularis cause cystic and alveolar hydatid disease respectively while E. vogeli and E. oligarthus rarely infect humans. Hydatid cyst of the gall bladder is extremely rare and this case report highlights the rarest location of hydatid disease.