PURPOSE: To evaluate the enhancement patterns revealed by dual-phase CT, and other characteristic features of nodular hepatic involvement of malignant lymphoma, and to determine the usefulness of this imaging modality in the differentiatial diagnosis of hepatic masses. MATERIALS AND METHODS: Seven cases that pathologically confirmed as nodular hepatic involvements of malignant lymphoma among patients who underwent dual-phase CT for the staging or follow-up of malignant lymphoma, and two that confirmed as primary lymphoma among patients who underwent dual-phase CT for differential diagnosis of nodular hepatic masses were evaluated. There were eight cases of non-Hodgkin 's lymphoma (NHL) and one of Hodgkin 's disease(HD). The findings were analysed in terms of the number, size, and contour pattern of the masses, the enhancement pattern seen on dual-phase CT, and whether or not the vascular structure of the mass was normal. RESULTS: Primary lymphomas were present in two patients(single mass, n=1; multiple nodules, n=1) and secondary lymphomas in seven (single mass, n=6; multiple nodules, n=1). The maximum size of main masses was mean 5.1(range, 2-12) cm, and the contor was smooth in three cases, ill-defined in three and lobulated in three. During the early phase, five patients showed homogeneous low attenuation, and heterogeneous enhancement was observed in four. During the late phase, three of the five showed peripheral enhancement and the other two showed the same low attenuation, while two of the four showed central low attenuation, one showed iso attenuation, and one showed heterogeneous enhancement. In four of the patients whose main mass was larger than the mean, vascular shadow passed through the mass (left portal vein, n=2; branches of the right portal vein, n=1; and branches of the hepatic artery, n=1). CONCLUSION: Where dual-phase CT demonstrated nodular hepatic involvement of malignant lymphoma, contrast enhancement varied and so differentiation from other hepatic masses such as metastatic adenocarcinoma and hepatocellular carcinoma was therefore difficult. Homogeneity and a lack of necrosis, even though a mass is large and has a smooth well-defined contour, no capsulation and normal vasculature, may suggest the nodular hepatic involvement of malignant lymphoma.