Primary hydatid disease in a retroplaced gallbladder.

A 60-year-old man with abdominal distension, fever, vomiting and pain on the right upper quadrant of the abdomen was admitted to our hospital. US revealed a well circumscribed lesion of mixed echogenicity. CT revealed hypoplasia of the right liver lobe, and a cystic mass with solid components replacing a retroplaced gallbladder. On T1-weighted MR images the lesion had low signal intensity and presented mild peripheral post-contrast enhancement, while on T2-weighted images the periphery was of moderately high signal intensity and the centre of fluid-like, high signal intensity. Adjacent liver parenchyma had relatively high signal intensity on T2-weighted images. The patient underwent exploratory laparotomy, and a hydatid cyst of the gallbladder that was inflamed was evidenced.