[Study of sonographic findings of small hepatocellular carcinoma based on its pathologic findings].

Sonograms of 282 cases of hepatocellular carcinoma (HCC) less than 5 cm in size were examined. Among these, 73 cases of resected or biopsied HCCs were compared in terms of their pathologic findings and sonograms. Low echoic pattern was the more common among smaller HCCs, and low echoic periphery pattern tended to prevail with increasing size. The pathologic factors of fatty change and clear cell formation are responsible for elevating the echo level. Among HCCs less than 2 cm, the low echoic group is more differentiated than the iso-echoic group by Edmondson's classification. "Lateral acoustic shadow", "nodule in nodule", and "septum" are characteristic findings in HCC by sonography, and they correspond to the pathologic findings. However, "posterior echo enhancement" was not seen to be specific for HCC, as it was also observed with similarly frequency in hemangiomas.