Focal nodular hyperplasia mimicking hepatocellular carcinoma in a patient with chronic hepatitis B and representing a diagnostic pitfall

Ryu, Tom; Jeong, Soung won; Chang, Young; Jang, Jae Young; Ryu, Tom; Jeong, Soung won; Chang, Young; Jang, Jae Young

Tom Ryu, Soung won Jeong

, Young Chang, Jae Young Jang

Soon Chun Hyang University Hospital, Seoul, Korea

Address for Correspondence:

Soung won Jeong ,Tel: 82-2-709-9581, Fax: 82-2-709-9696, Email: jeongsw@schmc.ac.kr

Received: 15 April 2026; Accepted: 12 May 2026. Published online: 12 May 2026.

ABSTRACT

We report a case of a 51-year-old man with chronic hepatitis B (CHB) in whom a small hepatic lesion was incidentally detected during routine surveillance. Dynamic computed tomography and gadoxetic acid-enhanced magnetic resonance imaging demonstrated arterial hyperenhancement with hepatobiliary phase washout, raising strong suspicion for hepatocellular carcinoma (HCC). However, serum tumor markers were within normal ranges, and there was no evidence of advanced fibrosis, although HCC might still occur in such patients with CHB. Contrast-enhanced ultrasonography (CEUS) using Sonazoid® revealed delayed and mild washout, which is atypical for HCC and suggested a benign lesion. Given the discordance between imaging findings and clinical context, ultrasound-guided liver biopsy was performed. Histopathological examination confirmed focal nodular hyperplasia (FNH). This case highlights a diagnostic pitfall in differentiating FNH from HCC in CHB patients and emphasizes the importance of integrating clinical findings with imaging features, to avoid misdiagnosis and unnecessary intervention.

Keywords: Focal nodular hyperplasia; Hepatocellular carcinoma; Contrast-enhanced ultrasonography