Advanced Hepatocellular Carcinoma Missed on Ultrasonography: A Case Report

We report the case of a 59-year-old man with chronic hepatitis B–related liver cirrhosis who developed diffuse hepatocellular carcinoma (HCC) with portal vein thrombosis (PVT) within only six months despite ongoing antiviral therapy. Importantly, initial surveillance ultrasonography failed to detect any definite malignant lesions, and serum alpha-fetoprotein remained within normal range, suggesting potential limitations for ultrasound in identifying early or infiltrative forms of HCC. At the 6-month follow-up, new-onset PVT was found incidentally on ultrasound, which became the key diagnostic clue leading to the detection of infiltrative HCC. Transarterial chemoembolization and radiation therapy, followed by splenic artery embolization for thrombocytopenia management were performed. Subsequently, a multidisciplinary approach enabled curative left hemihepatectomy with portal thrombectomy, which was successful. This case highlights that even in regular surveillance programs, HCC may be missed on initial ultrasonography, emphasizing the need for careful assessment of subtle vascular or parenchymal changes and the importance of integrating complementary imaging modalities.