96 The Korean Journal of Hepatology Vol. 18. No. 1, March 2012 A B Figure 3. Contrast-enhanced CT scan images taken on emergent admission. (A) Horizontal section. A contrast-enhanced CT scan of the upper abdomen demonstrating hepatic necrosis with emphysematous change (open arrow)-a totally emphysematous lesion in the right lobe of the liver. (B) Coronal section. CT scan showing pneumoperitoneum in the perihepatic space (white arrows). The black arrow shows an endoscopic retrograde biliary drainage tube. transaminase 978 IU/L, alanine transaminase 257 IU/L, alkaline phosphatase 367 IU/L, total bilirubin 27.4 mg/dL, blood urea nitrogen 50.2 mg/dL, creatitine 1.2 mg/dL, prothrombin time INR 1.19. Clostridium perfringens and Escherichia coli were grown on blood culture. She was empirically treated with cefotaxime and metronidazol. Despite intensive therapy in the ICU, the patient’s condition did not show improvement and she expired on the third day of admission. DISCUSSION Intra-abdominal emphysematous infections have not been uncommonly found in many organs, including the urinary tract, gallbladder, uterus, stomach, and pancreas1; however, a few have been found in the liver or biliary system. In liver, emphysematous condition can be seen in pyogenic liver abscesses by gas-forming abscess or after invasive procedures, such as transarterial embolization, radiofrequency ablation, and percutaneous ethanol injection in hepatocellular carcinoma,2,3,7,8 of which cases have been seen only in the portion of the affected lesion. Therefore, emphysematous replacement of a liver is an extremely rare clinical condition. The usual CT finding of pyogenic liver abscess is clustered or multi-septated lesion with fluid collection of surrounding parenchymal edema.6,9,10 In few cases of gas-forming pyogenic liver abscess, air bubbles or an air-fluid level can be revealed with localization in the involved area. On the other hand, in our case, the affected liver was totally replaced by air with no fluid content. Another differentiating disease, gas gangrene in the liver, which requires compromise of the both hepatic arterial and portal venous supplies, has been reported in the clinical setting of hepatic trauma or liver transplantation.4,5,11,12 Although parenchymal gas bubbles can be found in these conditions, like our case, parenchymal necrosis with emphysematous change is not feasible and pneumobilia is usually accompanied in cases of gas gangrene. Since both hepatic artery and portal veins were patent on CT scan and there was no history of diabetes mellitus and atherosclerosis, differentiation is easily possible. In addition, our case differs from radiation induced liver disease (RILD). RILD, often called radiation hepatitis, typically occur between 2 weeks to 3 months after therapy.13 Broad guidelines for normal liver dose constraints, for 5% or less risk of RILD, is a whole liver dose of 28-30 Gy in 2 Gy per fraction or a mean normal liver dose (liver minus gross tumor volume) of 28-32 Gy in 2 Gy per fractions.14 The CT findings that favor RILD were seen in areas of low attenuation resulting from either edema or vascular congestion in the target volume that corresponded to the irradiated portion of the liver, a sharp line of demarcation corresponding to the external beam port, usually with an anteroposterior or oblique orientation.15 Our patient received a total dose of 16.2 Gy in 1.8 Gy per fraction and a mean normal liver dose of 6.0 Gy. The last radiation therapy was