Benign tumours of the liver
OVERVIEW AND CLASSIFICATION
Benign hepatic lesions include haemangioma, focal nodular hyperplasia (FNH), hepatocellular adenoma, simple cysts, biliary hamartomas and less common mesenchymal or developmental lesions. Many are incidental findings. The key surgical task is to distinguish benign lesions from malignancy and identify lesions with haemorrhage or malignant-transformation risk.
CAVERNOUS HAEMANGIOMA
The commonest benign liver tumour is a vascular malformation composed of blood-filled spaces lined by endothelium. Most are small, asymptomatic and stable. Large lesions may cause discomfort or mass effect; rupture is very rare. Ultrasound often shows a well-defined hyperechoic lesion. Typical contrast imaging demonstrates peripheral discontinuous nodular enhancement with progressive centripetal fill-in. A typical asymptomatic haemangioma requires no treatment or routine follow-up. Avoid biopsy when imaging is characteristic because of bleeding risk. Intervention is considered only for significant symptoms, complications or diagnostic uncertainty after multidisciplinary review.
FOCAL NODULAR HYPERPLASIA
FNH is a benign hyperplastic response to an abnormal arterial supply, with a central stellate scar and radiating fibrous septa. It is usually asymptomatic, has no meaningful malignant potential and rarely bleeds. MRI with hepatobiliary contrast is highly useful: arterial hyperenhancement and uptake on hepatobiliary phase support FNH. No treatment is needed when imaging is typical; surgery is rarely required unless diagnosis remains uncertain or symptoms are convincingly attributable.
HEPATOCELLULAR ADENOMA
Adenoma is a true hepatocellular neoplasm associated with oestrogen-containing oral contraceptives, anabolic steroids, obesity and metabolic syndrome. Subtypes include HNF1A-inactivated, inflammatory, β-catenin-activated and unclassified lesions. β-catenin activation carries greater malignant-transformation risk. Complications are intratumoural haemorrhage/rupture and transformation to hepatocellular carcinoma. MRI helps subtype lesions. Management includes stopping hormonal/anabolic triggers, weight reduction and interval imaging. Resection is generally considered in men, β-catenin-mutated lesions, lesions ≥5 cm, growth, symptoms or haemorrhage; decisions depend on sex, subtype, size and patient context.
INVESTIGATIONS AND DIFFERENTIAL
Take a history of cancer, chronic liver disease, viral hepatitis, alcohol, medications, anabolic steroids, pregnancy and metabolic risk. Liver ultrasound is often the initial test; multiphasic contrast CT or MRI characterises enhancement, fat, scar and haemorrhage. Assess liver function and relevant tumour markers only when clinically indicated. Differential diagnosis includes HCC, metastasis, cholangiocarcinoma and hydatid disease. Biopsy is reserved for cases where imaging is indeterminate and histology will change management, after specialist assessment.