The natural history of hepatocellular adenoma: long-term outcomes from a large tertiary centre

Hepatocellular adenoma (HCA) is a benign liver tumour with variable biological behaviour and a recognised risk of haemorrhage and malignant transformation. Evidence on long-term natural history in mixed-management cohorts remains limited. This study reports clinical features, radiological behaviour and outcomes from a large tertiary centre.

A retrospective review was undertaken of all radiologically or histologically confirmed HCAs over a 17-year period. Diagnosis was based primarily on cross-sectional imaging, with biopsy reserved for atypical lesions. Patients were managed with surveillance, resection or transplantation.

From 2005 to 2022, 164 patients were identified, predominantly female (86.6%) with a median age of 36 years. Risk factors were present in 78.7%, most commonly oral contraceptive exposure and metabolic syndrome; syndromic disease accounted for 7.3%. Most tumours were incidental (70.7%); rupture occurred in three patients (1.8%). Histology ( n  = 86) showed inflammatory HCA as the most common subtype (40.7%), followed by hepatocyte nuclear factor 1a-mutated (24.4%) and β-catenin-mutated (8.1%). Surveillance was the main strategy (76.2%), with radiological regression in 18%. Resection was undertaken in 23.8% and transplantation in 5.5%. Malignant transformation occurred in six cases (3.7%), all within β-catenin-mutated or inflammatory adenomas.

Most HCAs were safely managed with surveillance, while malignant transformation was rare and restricted to high-risk molecular subtypes, supporting a conservative, risk-stratified approach.