Liver cell adenoma: a multicenter analysis of risk factors for rupture and malignancy.

BACKGROUND: Liver cell adenoma (LCA) is a benign hepatic tumor with poorly characterized risk for spontaneous rupture and malignant transformation.
METHODS: Records from five tertiary hepatobiliary centers were reviewed for all patients treated for LCA from 1997 to 2006. Clinicopathological data were collected and analyzed, and factors that were associated with rupture and/or malignant transformation were assessed by using multivariable logistic regression.
RESULTS: A total of 124 patients were analyzed, of which 8 (6.5%) were men; 119 patients underwent resection, and 5 patients had embolic therapy only. Mean patient age was 39+/-11 years, and 55% had history of hormone use. Rupture occurred in 31 (25%) cases. Ruptured tumors were larger (10.5+/-4.5 cm vs. 7.2+/-4.8 cm; p=0.001), and no tumor <5 cm ruptured. Patients with ruptured LCAs were more likely to require preoperative blood transfusion (32% vs. 9%, p=0.006), preoperative embolization (16% vs. 1%, p=0.021), and major (>or=3 segments) hepatic resection (65% vs. 32%, p=0.003). By multivariate analysis, increasing tumor size (odds ratio (OR), 7.8; 95% confidence interval (CI), 2.2-26.3; p<0.01) and recent (within 6 months) hormone use (OR, 4.5; 95% CI, 1.5-13.3; p<0.01) remained independently associated with risk of rupture. Five cases (4%) had evidence of underlying malignancy, but none had LCA <8 cm in diameter.
CONCLUSION: In this multicenter analysis of patients with LCAs, risk of rupture correlated with increasing tumor size and recent hormone use. Rupture is associated with greater need for preoperative blood transfusion and major hepatic resection. These data suggest that patients with asymptomatic LCAs approaching 4 cm and those requiring hormonal therapy should undergo surgical therapy.