Huge liver abscess radiologically mimicking cystadenocarcinoma

A 72-old-year Japanese man was incidentally found to have out liver dysfunction on serum examination and a cystic tumor in the liver. Dynamic computed tomography revealed a solitary cystic tumor 14 cm in diameter with multiple septa. The cyst wall was occasionally irregular with hyperarterial inflow. After admission, he suffered from fever and right upper abdominal pain. We suspected cystadenocarcinoma with intraluminal infection. Percutaneous transhepatic drainage was performed. However, neither cytologic examination nor culture test was positive. The cystic tumor had been decreasing in size, and hepatic resection performed. Macroscopically, the tumor was a gray-yellow solid tumor with a fine boundary between tumor and liver parenchyma, and the cystic lesion collapsed. Microscopically, the tumor consisted of hepatic infarction, degenerated Glisson's sheath, and chronic inflammation, and chronic liver abscess was diagnosed. Most cases of bacterial liver abscess can be diagnosed because progression is accompanied by typical signs. However, it is difficult to diagnose liver abscess in the chronic phase because chronic liver abscesses exhibit various features on imaging series without typical signs or symptoms. When atypical liver cyst is found, the possibility of liver abscess in chronic phase should be considered.