Natural course of small nodular lesions with intranodular preserved portal supply in cirrhotic liver

Background and Aim: Due to recent advances in imaging technology, small nodules or lesions in cirrhotic liver are now seen easily. Intranodular blood supply is useful in characterizing these nodules. However, nodules with preserved portal blood supply may be malignant or benign, and it is unknown how often these nodules develop into overt hepatocellular carcinoma (HCC). This study was performed to clarify the rate of malignant transformation in such lesions with preserved portal perfusion in cirrhotic liver. Methods: From 1995 to 1997, in 98 patients, we performed CT during arterial portography and ultrasound angiography with intraarterial CO2 injection for 113 nodules < 3 cm in diameter to determine the intranodular blood supply. Of these, 48 nodules in 36 patients were diagnosed as 'benign nature nodules' on the basis of the blood supply of the nodules, which included arterial hypovascularity with preserved portal supply. Percutaneous biopsy of the nodule was undertaken for all nodules for histopathologic diagnosis. Thirty-two nodules in 22 patients that were not diagnosed as early HCC were followed-up clinically without any treatment to clarify the natural course of the nodules. Results: Twelve nodules in 14 patients did not increase in size and no new nodules appeared in any part of the liver. Ten nodules in 7 patients did not increase in size or arterial vascularity but typical overt HCC appeared in other areas of the liver. Only two nodules in 2 patients increased in size and developed into hypervascular overt HCC during the 15- and 34-month observation periods, respectively. Conclusion: Nodules with preserved portal perfusion in cirrhotic liver have a low risk of malignant transformation compared with the surrounding liver parenchyma.