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 χ² tests were performed to compare the results between the different subtypes. A Bonferroni correction was applied to correct for multiple testing (α < .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 β-catenin-positive HCAs (P = .003). No specific MR imaging features were identified for the unclassified cases.

CONCLUSION: L-FABP-negative, inflammatory, and β-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 β-catenin-positive HCAs are considered premalignant, closer follow-up with MR imaging or resection may be preferred.