A Case Report of an Inflammatory Hepatocellular Adenoma Mimicking Hepatocellular Carcinoma in a Patient with Alcoholic Cirrhosis.

[BACKGROUND] Hepatocellular adenoma (HCA) is a benign liver tumor that can mimic hepatocellular carcinoma (HCC), especially in patients with cirrhosis. Inflammatory HCA, a subtype of HCA, is characterized by increased expression of inflammation-related proteins such as serum amyloid A (SAA). Distinguishing inflammatory HCA from other liver lesions, such as HCC, can be challenging on imaging, especially in cirrhotic livers.

[CASE PRESENTATION] A 44-year-old male with alcoholic liver cirrhosis was found to have a hepatic lesion in segment 8, which gradually increased in size from 15 mm to 47 mm over four years. The lesion exhibited arterial phase hyperenhancement (APHE) and washout on delayed imaging. It fulfilled the Liver Imaging Reporting and Data System (LI-RADS) v2018 criteria for LR-5, indicating definite HCC. The patient underwent laparoscopic subsegmentectomy of segment 8 without prior biopsy. Histopathological examination confirmed the diagnosis of inflammatory HCA. Immunohistochemistry showed strong and diffuse expression of SAA and C-Reactive Protein (CRP), and no aberrant β-catenin expression. The lesion was initially diagnosed as HCC based on radiologic features; the final diagnosis was inflammatory HCA. The patient recovered well after surgery and was discharged nine days later.

[CONCLUSION] Inflammatory HCA can mimic HCC on imaging, especially in patients with alcoholic cirrhosis. In such cases, relying solely on imaging may lead to misdiagnosis. Correlation with clinical history, pathology, and immunohistochemical findings is important to avoid unnecessary surgery and ensure accurate diagnosis.