Hepatocellular Adenomas: Correlation of MR Imaging Findings with Pathologic Subtype Classification

Purpose: To investigate the correlation between magnetic resonance (MR) imaging findings and pathologic subtype classification of hepatocellular adenoma (HCA). Materials and Methods: This retrospective study was approved by the institutional review board, and the requirement for informed consent was waived. MR imaging studies of 61 lesions (48 patients; median age, 36 years) were available and were independently reviewed by two radiologists. Consensus readings on all morphologic and signal-intensity imaging features were obtained. Previously, these lesions had been classified on the basis of pathologic findings and immunohistochemical analysis. Fisher exact and chi(2) tests were performed to compare the results between the different subtypes. A Bonferroni correction was applied to correct for multiple testing (alpha < .0033). Results: MR imaging signs of diffuse intratumoral fat deposition were present in seven (78%) of nine liver-fatty acid binding protein (L-FABP)-negative HCAs compared with five (17%) of 29 inflammatory HCAs (P = .001). Steatosis within the nontumoral liver was present in 11 (38%) of 29 inflammatory HCAs compared with none of the L-FABP-negative HCAs (P = .038). A characteristic atoll sign was only seen in the inflammatory group (P = .027). Presence of a typical vaguely defined type of scar was seen in five (71%) of seven beta-catenin-positive HCAs (P = .003). No specific MR imaging features were identified for the unclassified cases. Conclusion: L-FABP-negative, inflammatory, and beta-catenin-positive HCAs were related to MR imaging signs of diffuse intratumoral fat deposition, an atoll sign, and a typical vaguely defined scar, respectively. Since beta-catenin-positive HCAs are considered premalignant, closer follow-up with MR imaging or resection may be preferred.