Can focal nodular hyperplasia transform into hepatocellular carcinoma? A 20-year journey from benign to malignant

This case presents a progression from benign focal nodular hyperplasia (FNH) to hepatocellular carcinoma (HCC) in a middle-aged patient undergoing private testosterone therapy for andropause. The patient presented to their general practitioner with fatigue and pruritus; routine blood tests showed deranged liver function tests. Historical records indicated a large FNH lesion that was stable for decades and required no intervention. Subsequent imaging demonstrated a mass within the right lobe suggestive of malignant transformation. Multidisciplinary discussion concluded the lesion likely represented HCC or hepatic adenoma. The patient underwent a successful robotic right hemihepatectomy. Histopathology confirmed well-differentiated HCC with macroscopic vascular invasion (pT2N0M0). Postoperative imaging showed no evidence of recurrence or metastasis, and liver function returned to normal. This case underscores the potential for malignant transformation in large FNH-like lesions despite prolonged radiological stability. It emphasises the role of imaging surveillance and robotic surgery as effective curative strategies.