Are Hepatic Adenomas Premalignant?

Objective: To investigate clinical experience with the apparent malignant transformation of benign liver cell adenomas. Design: Retrospective review of personal experience and literature. Setting: University hospital and affiliated community hospitals. Patients: All patients diagnosed with liver cell adenomas over a 30-year period. Interventions: Liver resection and/or tumor biopsy. Main Outcome Measures: Gender, age, drug associations, alpha-fetoprotein levels, response to treatment, and survival. Results: Thirteen patients from personal experience and 26 patients from the reports of others had liver cell adenomas that were not resected. Five of these patients subsequently developed hepatocellular carcinoma. Conclusions: Malignant transformation of a liver cell adenoma is a rare phenomenon, but it does occur. Alphafetoprotein levels may be more helpful in diagnosis than expected from previous reports. Solitary benign adenomas should be resected whenever possible. Patients with diffuse multiple tumors should be observed closely over a long period.