An unusual hyperplastic hepatocellular nodule in a patient with hepatitis C virus-related liver cirrhosis

Recent advances in diagnostic imaging techniques have increased the likelihood of detecting novel nodular lesions of the liver. We report here a case of unusual hyperplastic hepatocellular tumor found in a 70-yr-old woman with hepatitis C virus-related cirrhosis. A mass was incidentally detected in the right lobe by abdominal ultrasonography and confirmed by computed axial tomography (CT). Magnetic resonance imaging demonstrated that the tumor had hyperintense signal with a small hypointense region in the center and a thin, hypointense rim on T1-weighted image and a hypointense signal on T2-weighted image. CT during hepatic arteriography showed that the tumor was hypodense with a central hyperdense region, whereas CT during arterial portography revealed that the tumor was isodense and surrounded by a thin circular hypodense band with a central hypodense region. These radiographic findings suggested a diagnosis of dysplastic nodule with malignant foci of hepatocellular carcinoma. The patient underwent tumor resection. Macroscopically, the tumor, 45 x 45 x 30 mm in size, was encapsulated and had a central stellate-like scar with radiating septa. Histological examination showed a hyperplastic hepatocellular tumor without cellular, nuclear or structural atypia. The central fibrous scar contained abundant small, artery-like and vein-like vessels, whereas there were no normal portal triads but rather several portal tract-like structures lacking bile ducts in the parenchyma of the tumor. Some of the portal tract-like structures were composed of artery-like and vein-like vessels, and the others possessed vein-like vessels only. There were no bile ducts in the tumor. The nontumorous liver tissue had evidence of macronodular cirrhosis. Finally, this tumor was regarded as an unusual type of hyperplastic hepatocellular nodule encountered in cirrhotic liver, characterized by the presence of central stellate-like fibrosis and the lack of bile ducts. Although the pathogenesis of the hyperplastic lesion is unclear, it may represent a focal regenerative hepatocellular response to localized circulatory disorder.