Aim: A hyperenhanced rim (termed ‘HER') in the postvascular phase is detected in some cases of liver metastasis by Sonazoid-enhanced ultrasonography (US). Here, the association of the HER with histological features was investigated to clarify the cause of this characteristic imaging pattern. Subjects and Methods: A total of 13 hepatic nodules obtained from 11 patients with metastatic liver cancer who underwent Sonazoid-enhanced US followed by surgical resection were analyzed. The distribution density of CD68-positive cells in the tumor rim and the nontumor area was calculated and compared between the HER-positive and HER-negative groups. The relation between the pathological features of the tumor rim and the rate of necrosis within the tumor was also investigated. Results: In the HER-positive group (n = 8), the distribution density of CD68-positive cells was 2.9 ± 0.9, which was significantly higher than that (1.0 ± 0.3) in the HER-negative group (p < 0.05). Inflammatory cell infiltrates, including CD8-positive lymphocytes, were detected in all the HER-positive cases in the area surrounding the tumor, while fibrosis was observed in all the HER-negative cases. The necrotic area within the tumor was significantly larger in the HER-negative group. Conclusion: The HER-positive sign in liver metastases could reflect an increase in Kupffer cells in the tumor rim. The presence of the HER was associated with inflammatory cell infiltrates including CD8-positive lymphocytes surrounding the metastatic liver tumor.