Men with biopsy-confirmed hepatocellular adenoma have a high risk of progression to hepatocellular carcinoma: A nationwide population-based study.

BACKGROUND & AIMS: Hepatocellular adenoma is a benign liver tumour that may transform to hepatocellular carcinoma (HCC). We used data from Danish nationwide healthcare registries to investigate the incidence and prognosis of hepatocellular adenoma.

METHODS: We included all patients with a hospital discharge diagnosis for benign liver tumour (ICD-10: D13.4) in 1997-2012 and a liver biopsy confirming the hepatocellular adenoma diagnosis. Follow-up began 1 year after adenoma diagnosis, to minimise the possibility that the tumour was a misdiagnosed HCC. All patients were age- and gender-matched with 50 random controls from the Danish population. We followed patients and controls with respect to HCC development, adenoma resection, and death without HCC (ie, death without having been diagnosed with HCC) through 2013. HCC diagnoses were identified in the Danish Cancer Registry.

RESULTS: We included 67 patients with hepatocellular adenoma, and 58 (87%) were women. The overall incidence rate of histologically verified hepatocellular adenoma in the Danish general population was 0.07 (95% CI: 0.06-0.09) per 100 000 population per year. Fifteen patients had their adenoma resected before follow-up began, leaving 52 patients for follow-up. Men with biopsy-confirmed hepatocellular adenoma had a 10-year cumulative HCC risk as high as 60.0% (95% CI: 15.3%-87.0%). All men who developed HCC were older than 50 years at adenoma diagnosis. By contrast, none of the 44 women in the follow-up analysis developed HCC.

CONCLUSION: Histologically verified hepatocellular adenoma is rare in Denmark. It is a minor concern for women, but men have a very high risk of progression to HCC.