PURPOSE: The aim of this study is to correlate the non-characteristic dual-phase CT imaging findings of hepato-cellular carcinoma with the observed characteristics of surgical specimens. MATERIALS AND METHODS: We studied four cases in which homogeneous low attenuation was observed during the arterial and delayed phases of dynamic CT scanning and in which hepatocellular carcinoma with coagulation necrosis above 95% was pathologically confirmed. We compared the findings of dual phase CT scanning, ultrasonography, angiography and Lipiodol CT scanning with the observed features of surgical specimens. RESULTS: Nodules were 30-50 (mean, 41) mm in size, and were round in three cases and oval in one. In all four cases, a low density lesion was observed during the arterial and delayed phases of dual-phase CT scanning. Ultrasonography demonstrated internal echo and the presence of a hypoechoic halo, implying that in all cases a capsule was present. At angiography and LiCT, minimal peripheral and central tumor staining or lipiodol up-take was observed. In all surgical specimens a complete capsule was visible, and histologic structures were mainly of the trabecular type, Edmondson grade II or III was recorded, and the mass had undergone extensive coagulation necrosis (above 95%). CONCLUSION: In cirrhotic liver which is hepatitis B-antigen positive, clear sonographic findings of internal echo and a capsule, rather than a simple cyst, indicate the possibility of hepatocellular carcinoma with extensive coagulation necrosis. This is so even if the arterial and delayed phases of dual-phase CT scanning indicate the presence of a low-density lesion, and in such cases additional work-up is therefore required.