The peritumoral hypointense rim around hepatocellular carcinoma on T2*-weighted magnetic resonance imaging: radiologic–pathologic correlation

BACKGROUND: A peritumoral hypointense rim (PTHR) is sometimes observed around hepatocellular carcinoma (HCC) on T2*-weighted images (T2*WIs). We aimed to investigate the association between the PTHR and histopathologic findings on T2*WIs. METHODS: We assessed the presence of a PTHR on T2*WIs in 39 pathologically proven HCCs from April 2012 to December 2013. Prussian blue staining was performed, and iron deposition was evaluated by semiquantitative and quantitative methods. Optical density was used in the quantitative methods. The associations between a PTHR on T2*WI and histopathologic peritumoral or background liver iron deposition were analyzed. RESULTS: A PTHR on T2*WI was observed in 23 of 39 (59%) HCCs. There was no significant difference in the histopathologic fibrous capsule findings (P = 0.394). In the semiquantitative methods, both peritumoral and background liver iron deposition grade were significantly higher in HCCs with a PTHR compared with HCCs without a PTHR (P < 0.001). The mean optical density in HCCs with a PTHR was significantly higher compared with HCCs without a PTHR, in the quantitative peritumoral (42,244.1 ± 20,854.9 vs. 18,739.1 ± 12,258.7, respectively; P < 0.001) and background liver iron deposition analyses (35,554.7 ± 19,854.8 vs. 17,292.4 ± 11,605.8, respectively; P < 0.001). Tumor size (P = 0.005), etiology (P = 0.001), and degree of fibrosis (P = 0.042) were significantly associated with the presence of a PTHR. CONCLUSIONS: A PTHR in HCCs on T2*WIs was strongly associated with peritumoral iron deposition in the iron-deposited background liver but not with the fibrous capsule.